Movement Science: Devotion to Motion

How did our early ancestors move across the world? How is Covid-19 impacting athletes?
01 December 2020

WALKING IN FOREST

photo of someone walking in a forest

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Through November we’ve been musing over the science of movement, from enormous planetary scales to tiny cellular ones. And so this week, to celebrate our devotion to motion, we bring you our Move n A! We'll be talking exercise, how animals get about, the wanderings of our early human ancestors, and movements under our feet, with a superstar panel of scientists and answering some of the questions you've been sending in...

In this episode

photograph of Charles Darwin

01:03 - Darwin's missing notebooks

Meet the panel of scientists behind the latest Naked Scientists show...

Darwin's missing notebooks
Dan Gordon, ARU; Emma Pomeroy, Cambridge Uni; Eleanor Drinkwater, York Uni; Jess Johnson, UEA

Katie Haylor chats to Dan Gordon, paralympian and exercise physiologist from Anglia Ruskin University; Cambridge University archeologist Emma Pomeroy; Eleanor Drinkwater from the University of York, and volcano and earthquake scientist Jess Johnson from UEA...

Katie - So let's introduce our panel. We have Dan Gordon, Paralympian and exercise physiologist from Anglia Ruskin University. Dan, I hear you've got a bit of a plan to get our blood pumping later on.

Dan - I thought a very short little exercise treat for everybody to get them raring, to get the brain cells going... yes.

Katie - How easy is it to teach sports science virtually? Because it's by definition quite a physical discipline.

Dan - It's been a real challenge. We've had to opt for having some of the sessions face to face - our practical sessions are still having to be face to face, if the students are able to do it - so we've adopted kind of a blended learning approach. It's certainly forced us to think about different ways that we are doing this practical... particularly where we're collecting respiratory air and respiratory gases, which are in essence aerosol-generating.

Katie - Ah. Yeah, I see the problem. We've also got Cambridge University archaeologist Emma Pomeroy. And Cambridge University has been in the news recently, hasn't it Emma, because of the news about Darwin's missing notebooks. Have you heard about this?

Emma - Yes, I have. And really quite a big story and quite shocking. They're such important notebooks. But there have been other cases where similar manuscripts have gone missing and turned up later, so I just hope that'll be the end of this story. We might draw some parallels with the illegal trade in antiquities, for example; and while something like this would clearly be very high profile, I'm sure there are private markets out there, just as there are for valuable archaeological artifacts, where people would still pay an awful lot of money and buy them on the quiet. So yeah, sadly so.

Katie - Also on the panel today is Eleanor Drinkwater, long-time friend of the show and our go-to animal... well, in fact, creepy crawly expert. You've been doing your PhD on wood lice personalities, and I always love having you on the show because we get to talk about how cute woodlice are. How's it going?

Eleanor - Yeah, it's going really, really well. Woodlouse personality is one of the most fascinating things on the planet. So next time you see a woodlouse, watch it for a little while and see whether you can figure out whether it's friendly, or shy, or bold, or not.

Katie - See, my problem is I've got two cats now and I'm not sure a woodlouse would survive in my garden for very long. I don't want to say that to a woodlouse expert, but that might be the case!

Eleanor - Well, they're probably much better at hiding than you expect. So you've probably got some healthy populations going on there, don't worry.

Katie - Oh ok, so I've selected for athletic woodlice, I get it. And we've also got volcano and earthquake scientist Jess Johnson from University of East Anglia. Jess, has the pandemic restricted any of your fieldwork, because you usually like to go to Hawaii and do lots of cool science, don't you?

Jess - Yes, it has unfortunately. I had a trip to Hawaii booked last year, or earlier in the year rather; we've had various trips to the Caribbean as well having to be canceled. But luckily we can still get quite a lot of our data, so we're still working away.

photo of monarch butterfly

04:14 - Insects on the move

Wildfires, stowaways and impressive migrators...

Insects on the move
Eleanor Drinkwater, Uni of York

Wildfires, stowaways and impressive migrators - insect expert Eleanor Drinkwater speaks to Katie Haylor about insect movement. First of all, they hear a clip from our Animals on the Move show from Murdoch University biosecurity expert Simon McKirdy, who surveyed a cruise ship floating near an Australian island with a unique ecosystem. He was looking for stowaway insects that could pose a threat to the biodiversity of the area. And one critter proved extremely difficult to remove from the boat...

Simon - An insect called tribolium destructor, a tiny little beetle - we're only talking a beetle of about five millimetres in length - but despite all the effort we put into hunting for this beetle, and baiting and trapping and chemical treatments, even at the end of the 19 months when that vessel sailed away, we had not managed to kill the population. We were still finding larvae on the last few days before it left.

Katie - Eleanor, the insects on this boat were moving not under their own steam, as it were, because this was a cruise liner coming from the Baltic to Australia; but how do insects fare in terms of moving great distances under their own steam?

Eleanor - This is such a great question. There are a few different long distance insects that we know about. For example, there's the very famous, very flashy monarch butterfly. They do travel pretty long distances; however, their distances are completely shot out of the water by a creature that very few people have heard of. There is an incredible dragonfly which is known as the globe skimmer or the wandering glider. This is a very small creature, so it's only about two inches long and about three inches across the wingspan. And unusually for dragonflies, it has these incredible long distance migrations. They have developed enlarged hind wings that allows them to glide for incredible distances. In fact they do this migration from East Africa to India, and then back again.

Katie - Wow!

Eleanor - Yes, exactly! Which is the distance of around about 18,000 kilometres, which is just mind-blowing. This is multi-generational; so you get different individuals who do different legs of the journey. But even the individuals themselves go extraordinary distances. For example, there is one stretch in which they have to cross the Indian Ocean, which is a distance of 3,500 kilometres, that individual insects that are no longer than two inches manage to do. Which is just extraordinary!

Katie - Eleanor it puts my lunchtime walk around the block to shame a little bit. But we were talking about Australia earlier, and this year we've seen some enormous wildfires across numerous parts of the world. And I was just wondering how in general animal movement can relate to extreme conditions like fires.

Eleanor - The obvious thing is -  a lot of animals, insects, are great to hiding from fires; so during the hot season they'll hide themselves in cracks and crevices. But what I find even more interesting is you get some insects who travel long distances towards the fires. In fact, some species like the black fire beetle: it needs fire in order to reproduce. So they use their sense of smell in order to detect fires, which long distances away, in order to be able to lay their eggs in recently burned wood. And their larvae can only develop if they have been grown in a piece of wood has been recently burned. And the fascinating thing is many of these animals are actually becoming quite rare because of the better fire management that we have these days.

Katie - That sounds like quite a tricky one from a biodiversity/conservation point of view, because there's massive amounts of animals that have perished in these wildfires; but on the other hand, you've got animals who actually require fire. Is that quite a difficult balancing act?

Eleanor - Yes, it is. It's really interesting because you get... it's not just these individuals who do very, very well, or need it to breed; but if you think about an area which has been burnt, suddenly there's no competition and there's very high nutrients in the soil, and also slightly raised temperatures. So there are certain species that do really well in these conditions, to the detriment of other individuals. So recently burnt areas are quite interesting from that point of view. But you're totally right that it does come at a big cost of a lot of other species. So it's a very difficult balancing act.

Vaccine

08:50 - Digesting the Ox/AZ vaccine developments

We digest the recent news about the Oxford University/Astra Zeneca Covid-19 vaccine candidate...

Digesting the Ox/AZ vaccine developments
Gillies O'Bryan Tear, Faculty of Pharmaceutical Medicine

Let’s turn our attention to some very relevant fast-moving science. Around the world, scientists are tirelessly working towards various Covid vaccines. We’ve heard about various candidates recently, including the Moderna vaccine, the Pfizer/BioNTech vaccine, and now news is out about the Oxford University/Astra Zeneca vaccine, whose “Phase 3 interim analysis including 131 Covid-19 cases indicates that the vaccine is 70.4% effective when combining data from two dosing regimens”. Gillies O’Bryan Tear from the Faculty of Pharmaceutical Medicine joins us to digest the recent announcements and what this actually means...

Gillies - The vaccine works by introducing DNA, which sends a message into the cells to make the spike protein from the coronavirus. Now in order to get into the cells, Oxford Virus sends the vaccine in using a vector, a carrying... if you like, a Trojan horse, which is in fact an inactivated virus which cannot replicate in the human body. It's sort of a weakened version of a common cold virus called adenovirus. Once the virus carries the DNA into the host cell, the human cells, the cells - our own body cells - start making, on the instruction of that DNA, the spike protein of the coronavirus. And the body then mounts an immune response to that spike protein, and the reason that disables the virus or prevents the virus from infecting the person who received the vaccine, is because the spike protein is what the virus uses to get into our bodies.

Katie - Who have they tested this vaccine on? Does it protect people who are actually most at risk?

Gillies - So far they've announced results of three phases of trials: the phase I trial; the phase II trial, which was published last week in the Lancet, a peer reviewed journal, in great detail - 560 participants in that trial, half of whom received the vaccine; and more recently they announced the interim results from the larger phase III trial, which has enrolled 24,000 people, half of whom received the vaccine and half of whom received a control vaccine, for meningitis as it happens. So in total they've enrolled tens of thousands of people, and they plan to enroll up to 60,000 people all over the world. And you ask whether they've enrolled people who are at high risk: the phase II results, in that study they enrolled people who were older, over 70, as well as younger people; and in a phase III trial they also enrolled people who are older. And because they've done the study all over the world, they've also enrolled a lot of people from different racial and ethnic backgrounds. As we know, the black and minority ethnic population are at higher risk from coronavirus, and elderly people are more at risk; that's well known. So they've made sure they've included in the trial those groups of patients, and encouragingly, from the phase II results we saw that the immune responses which the recipients of the vaccine mounted against the coronavirus were just as strong in the elderly people who were in the trial, over seventies, as in the younger ones. And that's significant because it's well known that older people have a weaker immune system than younger people.

Katie - Is this about preventing infection, or mitigating the consequences of getting COVID?

Gillies - The interim phase III results have shown both. It's been shown that it prevents COVID symptomatic illness in up to 90% of patients, depending on the doses used; but also it prevents severe illness, because no cases of severe illness were seen in the patients who received the COVID vaccine.

Katie - How safe is it?

Gillies - The phase II results have got very detailed safety data, and show the vaccine produces the normal side effects that most immunisations or vaccinations cause: a sore arm, sometimes a fever for a day or two, and a headache, which can all be treated with paracetamol. So it seems to be safe. There've be no serious adverse events reported on this trial.

Katie - So how well does this work? What's going on with these different response rates and different dosing regimens?

Gillies - Well, they enrolled patients at two different doses: a half dose followed by a full dose, and then another group received two full doses. Slightly counter-intuitively, they saw 90% efficacy in the first group who received a half dose followed by full dose, and a lower efficacy of 62% in the patients who received two full doses. Now vaccines are not like regular medicines, where the higher the dose, generally the higher the effect. And there may be one or two scientific reasons why this happened, but they are looking into that currently. But the important point is that even at the high dose-high dose regimen, they achieved very, very good efficacy; because if you remember, flu vaccination only vaccinates against 50% of cases. So it cleared the hurdle for an effective vaccine, and at the lower dose regime it was 90%; as effective as any other vaccines that have so far announced results.

Katie - What are the theories on why this half dose followed by a full dose seems to be better than full dose followed by full dose?

Gillies - One theory is that the body can mount an immune response to the vector. And if that's the case then it can reduce the efficacy of the vaccine, because its carrier is attacked by the body. Now it's possible that the low dose regime provoked a less brisk immune response to the vector than the high dose-high dose regimen. And that's one possible explanation, but they're still looking into this. There could be other explanations. AstraZeneca have said that the study was not initially designed to look at the lower dose, and that there was possibly some mishap that gave the patients a lower dose and they intended to; but first of all, a very large subgroup of patients did receive this lower dose, so it's a robust sample; and secondly, it probably doesn't matter in terms of the approval and the efficacy of this agent, because they've shown that it works very effectively and the regulators may choose to approve that lower dose because it has been shown to be more effective. We really await more results from the full publication and from AstraZeneca about what happened, exactly what happened.

Katie - Is it a fair question to ask you how this stacks up compared to other COVID vaccines in the making, or is it a bit too soon to be talking about that?

Gillies - It is too soon in the sense that all of these, the three announcements we've had, from three different programs, are all based on interim data, which is not the full data set, so that the numbers may change. However, I'd like to talk about the difference between efficacy on a clinical trial, in a very controlled setting, and effectiveness in stopping the pandemic, they're two different things, the Oxford AstraZeneca vaccine costs $3. It's very easy to transport and it's got very good efficacy. Even the blended efficacy rate is 70%. That is an extremely good efficacy rate. So even if it's got a slightly lower efficacy rate in clinical trials, doesn't mean that it's going to be less effective in containing the pandemic, because it's easier to get around the world. We need to stop this pandemic in all parts of the world, not just the Western world. So the fact that it's cheaper and easier to transport might mean that in the real world, it's the more effective vaccine. If you can understand that slight paradox.

Katie - What questions remain then? Because so far we haven't had a vaccine that's actually been approved by the regulators.

Gillies - Well, we anticipate regulatory approval before Christmas for at least two of these. I would imagine, at least an emergency use authorisation in the US for one or more of the messenger RNA vaccines. And the UK authorities are going to rapidly review the UK Oxford vaccine. And they'll be also reviewing the messenger RNA vaccines from Pfizer and Moderna. I think it's a very low probability they will not get approved. They will go through the proper review process though, looking at all the data. And secondly, of course, as I mentioned earlier, we've got unanswered questions about efficacy and safety. We need to see the full dataset. For example, how effective is the Oxford vaccine in the elderly? We know from the phase two results that the elderly have brisk immune responses, but does that translate into effectiveness, efficacy, in the big phase three trial? So there are a few unanswered questions still while we wait for the full results.

Do you know, nine months ago, we didn't even know if we could vaccinate against coronaviruses. Because we tried with MERS and SARS-1 and failed. And here we are nine months later, not only do we know we can vaccinate effectively, but in nine months we've got phase three trials of multi-tens of thousands of patients enrolled and we're nearing regulatory approval. It's an unprecedented achievement.

A volcano in New Zealand

18:23 - Extreme geology

How do volcanoes and earthquakes occur?

Extreme geology
Jess Johnson, UEA

Volcano expert Jess Johnson explains to Katie Haylor how extreme geological events like earthquakes and volcanoes happen. But first, Jess relates these events to the earth's tectonic plates, off the back of an interview from our Earth on the Move show from Hannah Sophia Davies from the University of Lisbon...

Hannah - There's plates being made and destroyed. So where the ocean is being made is at a mid-ocean Ridge. The big mountain range you see in the Atlantic, on maps of the Atlantic, that's where plate is being produced. And then where plate is destroyed, is in the subduction zone. So you see that in the Pacific ring of fire, this big ring of subduction zones where ocean plate sinks back into the earth and destroys it. As the plate sinks into the mantle, it pulls plates along with it. And so essentially the continents float around and they're being pulled and pushed by the ocean plate as it's being made and destroyed. And that's essentially how the plates move.

Katie - That was Hannah Sophia Davies from the University of Lisbon, from our Earth on the Move show, giving us a bit of a Geology 101. Jess, how do these dramatic events like volcanoes and earthquakes relate to the concept of Earth's plates?

Jess - As we've just heard, the Earth has a thin crust on the outside, which is what we live on. And that crust is split up into plates, and we call these tectonic plates, and they move around on the surface of the Earth. They do move slowly, but in some places they're moving apart. Some places they're moving together, and some places they're moving side to side. At the boundaries between the plates, that's where we're likely to get earthquakes and volcanoes. So where they move apart, pressure is released from the material underneath, and as it moves to fill the gap, that's where we get volcanoes. Where the plates move together, one plate often gets pushed beneath the other one, and the underlying plate releases water as it's squeezed. And the water travels up through the overlying plate, melts the material and in turn that causes volcanoes there. That third type of boundary though, where the plates move side to side, we don't often get volcanoes, but we do get large earthquakes. Earthquakes are usually caused when there's a relative movement between two plates, and that causes the rock to crack. They can be any size, they can be really tiny, that we won't even feel, but the big earthquakes that we hear about happen at these destructive plate boundaries, the subduction zones that you just heard about, and these are called megathrusts.

Katie - Where are these? Where in the world are we talking about?

Jess - They happen at the boundaries between plates. We heard in that clip, the Ring of Fire. So that goes all the way around the Pacific, because the Pacific plate is bounded by all of these other plates, that are kind of moving relative to that plate. Through the middle of the Atlantic, there's a plate boundary. There's a sort of newish one coming through Africa. But the UK is quite safe in the middle of one of these plates. We don't get very many earthquakes and we don't have any volcanoes. However, earthquakes can happen everywhere. It's not only at the plate boundaries that they happen. And often when earthquakes happen away from these plate boundaries, it's caused by old stresses. So stresses from where we used to be on a plate boundary, or even when the glaciers that used to cover the UK have melted, the plate is kind of rebounding slowly, and the stresses as that's moving, can cause small earthquakes.

Katie - So how good are scientists at predicting where a quake might happen, and what the impact is likely to be?

Jess - We're not very good at predicting earthquakes. They don't give us much warning. We can tell quite a lot. We can tell where an earthquake is likely to happen. Over long periods, we can tell which areas are likely to have more earthquakes. And we can say how big the biggest earthquakes are likely to be. But the actual trigger for large earthquakes is a bit of a random process. So telling exactly when an earthquake will occur is impossible, at the moment. We do model the impact of large earthquakes though. So we can tell where earthquakes are likely to happen, just not when, and we can tell from past earthquakes, we can look at current plate movement, and then we can assess what the shaking is likely to be. And we have to look at other things, like where people live, what sort of buildings they're in, to look at the impact that an earthquake might have.

Katie - What about volcanoes? Because I mean, I assume it's pretty obvious where a volcano is.

Jess - Yeah. Most of the time. Yeah. We're a bit better at forecasting volcanic eruptions, mainly because they give us more warning. We know where volcanoes are. We measure gases coming out of the ground. We measure deformation of the ground, when the magma reservoirs pressurise. And we also measure small earthquakes that are caused by magma breaking through the rock as it makes its way to the surface. So all of these clues tell us when a volcano is getting ready to erupt. Of course we need lots of monitoring equipment on the ground to gather all of those data, but even then it might do something unexpected, about half of the time when a volcano looks like it's about to erupt, it doesn't.

Katie - What is your research about at the moment?

Jess - My main research uses those small earthquakes around volcanoes to track the stresses in the rocks and fluids under the ground. At the moment, I'm working with data from the eruption in Hawaii in 2018, that people may have heard about. There were over 50,000 smaller earthquakes over about three months that accompanied that eruption. I take the earthquake waves, I measure them, and earthquake waves can actually be polarised in the same way that light can be. So because all rocks have these microscopic cracks in them. If you put pressure on a rock, the cracks, some of them close, some of them open, and they kind of all line up. And that means that earthquake waves will travel faster in one direction than the other, and that polarises the earthquake wave. So I use that polarisation to map the pressures and the fluids underground. I'm also involved in some other projects that work with communities, that live with natural hazards every day, to mitigate and reduce the risks that they live with. Currently working with people in Dominica in the Caribbean, and the idea is to create sustainable solutions to monitoring the hazards and reducing the risk.

city of Pompeii

25:13 - Unearthing Pompeii

New excavations have emerged in Pompeii archeological park...

Unearthing Pompeii
Emma Pomeroy, Cambridge University; Jess Johnson, UEA

One of the remarkable examples of volcano eruptions has to be Pompeii - the Roman City that was destroyed by the eruption of volcanic mount Vesuvius about 2000 years ago. Pompeii is particularly interesting because the volcanic ash ended up preserving the remains of the city and many of its inhabitants, providing a rich resource for scientists and archeologists today. And recently, the preserved remains of 2 more people have been unearthed in Pompeii archeological park. Katie Haylor spoke to archeologist Emma Pomeroy and volcano expert Jess Johnson...

Emma - So what they found are the remains of two individuals, as you said, they're two men, one seems to be older, perhaps between 30 and 40, and the other one younger. So in his late teens or early twenties. Now what they've actually found is, if you'd like, the void left behind by these men's bodies, when they were covered in ash. And then the bodies rotted away, the bones are still there. And so what they do when they find these voids, is pour in the material to take a cast of that hollow. By doing that, they can then see the actual shape of those people's bodies.

Katie - And Jess, how does a volcanic eruption end up freezing a city in time like this?

Jess - Well, one of the most deadly hazards from a volcanic eruption is called a pyroclastic density current. This is kind of like a flow, like an avalanche, but it's made up of volcanic ash, and boulders, combined with deadly gases, all at thousands of degrees, and traveling at hundreds of kilometres an hour. Very large pyroclastic density currents can create tens of metres of ash deposits. And in Pompeii, Mount Vesuvius had a large eruption, creating these pyroclastic density currents. In this case, probably the temperature likely killed the residents of Pompeii instantly, but then they were very quickly buried in the ash, as was the entire city. And so that is what preserved them.

Katie - Emma, what information can actually be gleaned from findings like this about, well, about things like what life was like for people in this ancient city?

Emma - A great deal. I mean, what's exciting about these individuals is, like I said, you've got the skeleton within these casts that they've been able to produce as well. So not only can we see the skeletal remains, and analyse them to look at things like age at death, whether individuals were male or female, and aspects of their life. So were they healthy? Did they suffer arthritis? All these kinds of questions. But then because we've got sort of the casts of their bodies as well, we can look at other things like what were they wearing? And in this case, the older man was wearing a woolen cloak, it looks like. And we can perhaps look at things that we can't tell very easily from the skeleton, what people's build and physique was like. And then you've got all the other evidence that gets preserved. So there's really remarkable sort of, everyday objects that come from Pompeii, including things like wooden furniture, and the remains of food, still in the bowls on tables, in some cases. It's really a whole host of evidence that actually, usually we don't get preserved in the archaeological record.

Katie - Now, Jess and Emma, I want to put this to you because on our forum, Peter's been wondering about volcanic ash. He says, the excavation of Pompeii must remove enormous quantities of this ash. So what do you do with it? How do you dispose of it? He reckons it might have a purpose as a soil improver. Emma, you probably deal with moving dirt and things around as an archaeologist. What happens to the stuff?

Emma - That's such a good question. And I'm actually really intrigued to know now what happens with the material from Pompeii. So usually in an excavation, we're usually removing just normal soil and sediment. And typically, unless the things that we're excavating are going to be left exposed for displays, such as Santorini or Pompeii, we actually fill back in the hole that we've excavated, partly to make it safe in some cases, sometimes because there's going to be new building work that takes place over the top, or sometimes perhaps to protect the remains that we have found for future generations. So quite often we actually put the material back. It's also important to remember that many archaeological excavations are not on the kind of scale that we're seeing in Pompeii. You know, it's really an amazing project that's been going on for such a long time. So that's a brilliant question. And actually in the case of Pompeii, I don't know, and would love to know.

cartoon of exercise with dumbbells

Dan Gordon's squat challenge
Dan Gordon, ARU

Before we get back to unearthing the ancient history of human movement, it’s time to get the blood pumping here in the studio and at home with some movement of our own. Dan Gordon, exercise expert, got Katie Haylor inspired with an exercise challenge...

Dan - If we've got space, stand up. All I'm going to ask everybody to do is, I will be the timekeeper, for 30 seconds - just do squats. Hands on your hips or hands on your head, and just try and do them as fast as you possibly can. We just want to get the blood pumping a little bit.

Katie - Are you gonna do them with us Dan?

Dan - I'm gonna do them! Don't you worry.

Katie - Okay! Right. Is everyone ready?

Dan - We're ready. Here we go. Three, two, one. Let's go.

Katie - I'll practice my err...I don't know about my technique actually, nevermind!

Dan - Nice and steady, and trying to do nice relatively deep squats. Feel a little bit of burn in your legs as well as you're going down.

Katie - Dan my thighs feel like lead!

Dan - Oh okay! We're just over halfway, so we're going really nicely, Just keep that going, keep the old up and down movement going - really good. Keep it nice and firm in the stomach as well, so you're just holding that position. We're nearly there. And stop, there we go!

Katie - Okay. Right. Finding my chair again. I think I got about 11. Did anyone do better than 11?

Emma - I totally lost count. I don't think I'm able to do exercise and think at the same time it seems!

Katie - Maybe you just did so many that it wasn't worth counting after a while.

Emma - Yeah. Maybe I was just lightning fast. Yeah. You're absolutely right.

Katie - Eleanor, are you going to admit your score?

Eleanor - Well, I did some and then I decided that it was awfully hard work and so I got some biscuits out instead, so I apologise.

Katie - Ah wow, I was going to tell you off, but I just have to admire that. That's excellent. Jess, what about you?

Jess - Yeah. Yeah. I got to 18, but I was trying to get real deep as well.

Katie - Blimey! Wow. Well, I think I'm going to give you a little round of applause there because that's certainly a lot better than my 11. Dan, can I ask you about warming up - forum user Carl89 has recently weighed in on a discussion on our Naked Scientists forum asking actually what the point of warming up is. And he reckons it's due to increasing blood flow and enhancing flexibility of muscles. Is that right? And if we're talking about warming up, does the external temperature matter?

Dan - Yeah, this is a great question, but it's also one of those questions which opens up a can of worms. If we take, for example, doing cardiovascular exercise, then the whole notion of doing a warm up for that kind of exercise is to absolutely raise temperature.

But what we're trying to do is raise the temperature at which the cellular processes are operating, because all cellular processes work at an optimal temperature. So if we can get those processes increased, the temperature increases the rate at which those processes operate, it's sped up and becomes more efficient. It's also designed, those kinds of warmups, to reduce what we call an oxygen deficit. And whenever we start to exercise what you perhaps feel for the first few minutes, the exercise always feels very hard. You feel like you're struggling to breathe and so on. And that's because the cardiovascular system, the aerobic supply of energy, our kind of use of carbohydrates are all delayed. They don't hit their instantaneous, what we call, steady state. So you borrow energy from sources, which we refer to as being anaerobic. And really the consequence of that is what makes it feel hard to exercise.

So if you can warm up beforehand, what the warm-up does is it raises things like your heart rate, it raises your respiration rate. It raises the metabolic rate. So when you actually get into doing the exercise that you really want to do, there's less of a lag. And so you actually hit that steady state more effectively. The flip side to all of this is what about warming up for sports or exercises like strength training. Because in those sports, there are no benefits at all in doing anything which is cardiovascular based because the exercise that you're going to do doesn't stress the cardiovascular system. So in those kinds of exercises, what we suggest to do is what is called post activation potentiation - it's a very fancy term isn't it.

But, in essence, what it's about is preparing the neuromuscular system. And if we can prepare the neuromuscular system, what we can do is recruit more what we call motor units and the motor units are basically how many muscle fibres are recruited from a nerve. And the more muscle fibres I can recruit from a nerve, the more force and therefore the more load in the gym I can lift. We don't have to worry about temperature. We don't have to worry about heart rate and we don't have to worry about the flexibility issue. So it's very different. Depends on the sport that we're going to work with. You talked about the environmental temperature. If the external environment temperature is cold, like we're starting to get now, then the warmup doesn't need to be more intense, but what it needs to do is be sufficiently stressful. And what I mean by that is putting a strain on the biological system to raise the temperature enough, to ensure that we've hit that kind of required point for the exercise. So we will take longer to warm up in colder conditions.

Earl human ancestors

Where our early ancestors wandered
Emma Pomeroy, Cambridge University

On our People on the Move show, we heard about science challenging our understanding of when our earliest ancestors moved out of the African continent.

Mathew  - This traditional idea of this exodus out of Africa at around 50,000 years ago, isn't entirely correct. There is growing both archeological and fossil evidence to suggest that we dispersed out of Africa earlier, all the way to Northern Australia by around about 65 - 70,000 years ago. The picture is just becoming much more complex. It appears that we left multiple times, that there were disposals back into Africa. It's adding to this much more complex picture.

That was Mathew Stewart from the Max Planck Institute for Chemical Ecology, talking in particular reference to the amazing finding of what they reckon are homosapian footprints in an ancient former lake in Arabia, dated to around 125,000 years ago. And this jars with the idea of an exodus out of Africa happening around 50,000- 60,000 years ago, as was previously thought. So to find out what else science is revealing about how our ancestors moved around our planet, Katie Haylor spoke to Cambridge University's Emma Pomeroy...

Katie - That was Mathew Stewart from the max Planck Institute for Chemical Ecology, talking in particular reference to these amazing findings of what they reckon are homosapien footprints in an ancient former lake in Arabia. Emma, let's go back to you. What is the broad picture as we now understand it about how our ancient ancestors came to move around the world?

Emma - As was mentioned in that clip, for a while we thought that we didn't really spread out of Africa, which is where we first evolved, until relatively recently - by which we mean 50,000 years ago. But actually we're getting various lines of evidence showing that humans did spread out of Africa much earlier than that. But the question is how permanent were those migrations? So we've got some early modern human remains, for example, in Greece now dated 210,000 years ago. So sort of four times as old as we were thinking before, but there's no other evidence then for some time. So perhaps these are early dispersals that aren't successful colonizations.

Katie - Wow. That's an incredibly long time ago, it's kind of boggling my brain a little bit. But how do our modern ancestors homosapians, how do they end up on different continents? Because I guess there's just walking places, but what if you've got a mass of water in the way?

Emma - Yeah. Humans get remarkably early to, for example, Australia, where some of the earliest evidence now is dating to 65,000 years ago. And of course there's multiple large bodies of water to cross to get there from mainland Asia. So we assume that they must have had watercraft of some sort. We don't have any evidence of that. They presumably were made of organic materials so haven't preserved and any depictions of watercraft only come much later, but it's really the only plausible explanation for getting to parts of the world like Australia.

Katie - What about the Americas?

Emma - We used to think that humans only really got to the Americas perhaps about 10,000 years ago or a little more. And that they got that crossing from Siberia over a land bridge that was there at the time. However, some of the evidence that we're now getting suggests that those dispersals might have been much earlier. There was a recent study of evidence from Mexico that was dated to 26,500 years ago. Now one of the routes that we originally thought people must've taken was down the so-called ice-free corridor. So at that time, the land bridge was covered in ice sheets. And there were certain times when a corridor opened up that people could have walked down. But given that we've now got these quite early dates another hypothesis is that people actually went along the coastline.

Katie - Once you've got humans all over the world, what about when people start to settle? Do we know much about the transition between having a more kind of hunter-gatherer lifestyle and when you start doing things like farming agriculture?

Emma - Yeah, we do. And there's some really interesting evidence again coming from the archeology, but supplemented with ancient DNA, particularly to really understand what these processes were like. So for example in Europe and Asia, the domesticated plants and animals that people come to rely on as farmers, came from an area called the Levant in Southwest Asia. For a long time there was a big debate, was this moving into Europe by diffusion? Or was it actually farmers moving from the Levant actually migrating into Europe, bringing their farming techniques with them? The genetic evidence has been showing some really interesting things. So it does suggest that actually there was a migration of people into Europe and in some places they almost completely replaced the existing hunter-gatherer populations. There was a study of remains from the UK and it suggested that perhaps 90% of the original hunter-gatherer population was replaced by these incoming farmers.

Katie - What about the other hominins that were around at the time? Because we're not just talking about homosapiens are we really.

Emma - If you'd have asked that question 20 years ago, we'd have said, well, it was just modern humans and there were then Neanderthals in Europe and Asia and maybe another species called homo erectus still in Asia. But there's been really incredible discoveries over the last 20 years. So we now have another species called homo floresiensis that survived to about 50,000 years ago. There's also homo luzonensis on the Island of Luzon in the Philippines. Homo naledi was still around about 230,000 years ago in Africa. We've got Vende Denisovans, this kind of enigmatic species that were identified only initially from DNA in mainland Asia. And then we've also got evidence that homo erectus were indeed still around in parts of Asia, like Java, until around 110,000 years ago. So yeah, when we're looking at that initial dispersal period, Europe and Asia and Africa were occupied by a whole range of species closely related to us. And it's only much more recently that we've become the only ones that are left.

Katie - So there's far more to hominin movement than just homosapiens then. Emma Pomeroy thanks ever so much.

photo of an Icelandic horse

43:03 - Do arctic horses migrate?

We put a listener question to our animal expert...

Do arctic horses migrate?
Eleanor Drinkwater, Uni of York

Listener Dave wants to know - I was reading an article about horses in the arctic protecting the permafrost, and was wondering if arctic horses migrate like caribou and some other arctic animals do? As it’s getting chilly here in the UK and we’re well and truly heading into winter, Katie Haylor put this fitting question to Eleanor Drinkwater...

Eleanor - The study that he talked about - so cool! 

Essentially using horses to protect permafrost because permafrost is kept at around minus 10 degrees. And then the snow is kind of insulating it to stop it from getting too cold, weirdly, as the air temperatures around minus 40 degrees.

So, if you put a bunch of horses in the area, they churn it up, and they reduce the temperature of permafrost, kind of protecting it, which is really interesting. As for whether or not they migrate, this is an excellent question, because actually pretty much all of the horses that we think about when we think about wild horses in Australia, in America, they're actually feral horses that have been released. So they're domesticated horses that have been released into the wild and kind of adapted to it. And actually we don't really know whether or not they would migrate.

So there has been a little bit of work done on some of the feral populations and they do move around a bit, depending on conditions around them. However what is unclear is whether or not in a wide open space they would migrate because a lot of populations now are kind of quite - penned in is perhaps the wrong word - but they have a limited distance which they can travel. So it might be the case that actually we're seeing no migration because they are not able to migrate, or it could be that they don't migrate.

So it's a really good question to which there's not a really clear answer.

table football

44:44 - Female footballers and brain injury risk

Is there a link between repeatedly heading footballs and dementia risk?

Female footballers and brain injury risk
Michael Grey, UEA

A question in the collective consciousness recently has been around footballers heading balls, and consequences for their brain health. Last year, Glasgow University published research showing that professional footballers were three-and-a-half times more likely to die from neurodegenerative disease. And now, scientists want to build on this research with a long term study that looks at people’s brains over time. With evidence that women experience more concussion that men in the sporting world, what does this mean for female footballers and the risks associated with heading a ball? Katie Haylor spoke to Michael Grey who's leading this study at UEA...

Michael - So we think that heading a ball causes something called sub-concussive trauma. So if we take concussions, for example, a concussion is a mild traumatic brain injury. It has a number of symptoms like headache, dizziness, feeling like one is in a fog. And that's occurring because of a direct result of damage to the neurons in the brain. A sub-concussive insult occurs because we're getting a bit of a lesser hit that doesn't cause a full-blown concussion, but there is still damage. And the idea is that by heading balls day after day, year after year, the neurodegeneration that builds up in the brain eventually leads to dementia.

Katie - How do you know this? What evidence have we got at the moment?

Michael - The direct evidence will come from animal models. Typically in mice and rats, one can induce a head injury of different kinds. One can look at the behaviour of the animal, and then we look at the brain and we can actually see tau proteins in the brain. We can see amyloid proteins in the brain, and we know that there has been degeneration.

Katie - So these are buildups or plaques that seem to be associated with the degeneration you get in things like Alzheimer's or dementia. Is that right?

Michael - Yes, that's absolutely correct. So when a nerve is damaged, we have a process called Wallerian degeneration. So the nerve dies, it breaks up. And then there are components of the nerve called tau proteins or amyloid proteins that are not soluble. So they actually stick around in the neurons. They adhere to the blood supply, they stop the blood supply and they prevent nerves from functioning and they cause other neurons to die.

Katie - Okay. So there is a pretty decent amount of evidence between the potential long-term effects of heading a football and problems with the brain. But where does the difference in sex come in?

Michael - Yeah. So the difference in sex is we think really important and it has been under studied. I mean, it is a fact that most of the studies of concussion, of sport-related neurodegeneration, they're all done in men. So one of the areas of concern for us is if you look at the statistics of dementia, specifically - in the UK, 61% of the population of people with dementia are women. Now some of that is because women live to a longer age and because it's a disease, obviously, that is more prevalent, the older one gets. That explains some of it, but it doesn't explain all of the difference in that ratio. The other thing that we have to look at is concussions themselves. We know that women experience concussion to a greater extent than do men. And if we put those two things together, it just makes sense that women are more likely to sustain the effects of sport-related neurodegeneration than men. And that's why we really need to study it.

Katie - If you were a betting man, do you have an idea of the mechanisms behind the sex differences? Because I guess there's physicality, but are there sort of hormonal changes that may be involved here? What's going on?

Michael - If you look at the mechanism of injury, you have to think about the brain as some jelly in a bowl. If I smack the side of the bowl, the jelly inside will wobble around. And the nerves that are in that jelly, that is the brain, they are damaged. Now, if we have a much stronger neck, for example, you can actually withstand that bubble of head effect. And therefore there's less wobbling of the brain than if we have weaker muscles. And we know that women are, on average, less muscular than men, particularly in their neck. So that's one area.

And if we look at the physiology, we think that there's an issue with women's cycles. So with the hormonal cycles, we think that women may actually be more at risk of concussion and therefore potentially the effects of neurodegeneration, depending on their cycles.

Katie - How could this inform how sport is done in the future? Because I guess you can't eliminate risk can you? I guess it must be about mitigation.

Michael - No, you're absolutely right. This is all about risk mitigation. We need to understand the risk before we can actually do something about it. And the idea here is it's about exposure to the injury in the first place. So one of the biggest things we can do is reduce exposure to heading the ball. In children for example. Personally, I don't think young children should be heading balls. I think that we can be doing the training in a different way. We can be strengthening the neck muscles, for example, long before we start to head the ball. And we can do things like reducing the amount of heading in practice, increasing the time between practices, where one might head the ball. And I think just by doing that alone, we will be making a difference.

runners on a track

50:25 - How are elite athletes faring with Covid?

How is the coronavirus pandemic impacting elite sport?

How are elite athletes faring with Covid?
Dan Gordon, ARU

How is the coronavirus pandemic impacting elite sport? To discuss this and more, Katie Haylor spoke to Dan Gordon, exercise phyiologist from Anglia Ruskin University...

Dan - Yeah. This is a really interesting question because I think there are some data now that are coming through which is anecdotal, which is suggesting the impact. If we look for example, to American sport, and we look at the NFL, and that pre-season has been massively reduced because of the global pandemic. So the teams were really unable to get the whole squads together. They had to have reduced squads. They couldn't have proper play throughs. And what started to actually happen is 1 - the actual leagues are completely topsy-turvy. And it's a bit like we're seeing, I suppose, in football, in the UK, the leagues are topsy-turvy. But the other thing that's really started to happen is there's a significantly increased number of injuries. Quite serious injuries as well, which go beyond the bounds of what you would normally expect to see in a competitive season.

Coupled with that, the other thing that we're starting to recognise is that when you are working with elite athletes, the whole aim of the game is to get athletes to peak, produce the optimal performance, on a day. They're all in essence, what we call a four year cycle, to prepare them for what would have been Tokyo 2020. And so suddenly the games are postponed, quite rightly. So the training has to change. So rather than going into a period of training, which they were anticipating on, which they'd be building towards to get them to a fine tuned physiological state and psychological state, they have to go back into what we call preparation training. What is going to be fascinating come Tokyo 2021, is really to be able to look and see which athletes have coped the best with this significant shift in the way in which they have had to focus training because their training cycle has been extended by over a year.

Katie - And I guess it depends on the sort of particular requirements of your sport. If you're a runner, then I can appreciate why your situation might be quite different to if you're a swimmer and you need access to a pool and the restrictions that go along with that. But what about sports people with different levels of mobility and disability?

Dan - We've just completed a study which is in review at the moment where we've been looking at the impact of the first lockdown on the way in which individuals who are blind or visually impaired in the UK could access facilities. And we compared those to a population of individuals with normal sight. And one of the things that we found was that individuals who are blind or visually impaired, there was a reduction in some types of physical activity that we're being done. So in the general population, people were going out for more walks and they were going out to walk the dog or whatever they were doing. But in the blind and visually impaired population, those situations were being stymied because they hadn't got access to, for example, support workers. They hadn't got access to the facilities they would normally use. A lot of people who are blind and visually impaired were telling us that they would use public transport to go and do their physical activity. And one of the big things that was a benefit, I think for most people who had normal sight, was of course using things like online videos to train with, you know, these kinds of campaigns to get people physically active. But what we found was people who were blind and visually impaired were unable to access these. And so they became very, very much marooned in terms of that, particularly the first lockdown period. I think we've learned a lot since then.

Katie - Dan, there are so many questions still around Covid-19 and the associated pandemic, but do we know that much about the impacts of Covid on athletes or the long haul Covid syndrome?

Dan - The honest truth is we generally don't. The evidence we've got from sports teams where they've been working with those athletes - and we know that certain sports were allowed to come back into the mainstream like football and cricket - the evidence coming out is that those individuals who are obviously more physically fit were more likely to not suffer from Covid. But we also have this evidence which is, as you become more physically fit and particularly at the elite level, it can actually potentially have a negative effect on your immune health. We have this situation called Nieman's J. Nieman's J is a theory around immunology and exercise, but it basically states that if you are very unfit, then you are quite immunosuppressed, you're more likely to get ill, and catch infections and so on. But as you are moderately fit and moderately well-trained, which is what we and the government are always trying to push for, actually you're able to cope more with illness and infection, we catch less colds and so on. But at the elite level, because of this stress that we've just been talking about being imposed on the body, both physically and emotionally, it imposes immune stress on the system and we become more susceptible to colds and illnesses and so on. So some of the thinking really is that it is likely that athletes, had they not gone into lockdown and isolated, would have been far more susceptible to Covid. They would have probably recovered better because they don't have the underlying health symptoms, but may have been more susceptible to catching Covid because of being immune suppressed to start with, compared to the general population.

A fly

57:24 - How high can a fly fly?

Do flies suffer from altitude sickness?

How high can a fly fly?
Eleanor Drinkwater, Uni of York

Eleanor Drinkwater answered listener Alex's question about how high a fly can fly...

Eleanor - If you think about the kinds of things that high altitude might affect an animal or particularly a fly, kinds of things that spring to mind are low oxygen levels, temperature - so particularly small insects find it difficult to thermoregulate so the temperature might be a big one. The higher you go, essentially the harder an insect would have to work in order to be able to keep flying.

I don't know whether or not the tallest building in the world would be tall enough to cause a fly any problems. That might depend on the fly. But there are some insects that it would definitely be no problem at all for.

You get some bumblebees that are incredibly well adapted in order to live particularly at high altitudes, and they do forage in the mountains. But when they took them into the lab to test just how high they could fly, they changed the air pressure to the equivalent of around about 9,000 metres, which is taller than the height of Everest, which is just quite extraordinary!

Remarkably, they found that they were totally fine and all they did was they shifted the way that they flew. So they didn't flap more because that would be un-energy efficient. Instead they kind of drew a wider arc with their wing in order to give themselves more lift, which they reckon is probably an adaptation which they've developed to allow themselves to carry lots of pollen and nectar. But actually it's also a really useful way of being able to deal with high altitudes as well. So if it's the alpine bumblebee, it definitely wouldn't be a problem at all.

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