Science of sitting down

At the start of the new year, some of us might have made resolutions to be a bit more active - and we need to be: according to one study the average brit will spend more than 18 years of their adult lifetime sitting down! But why is being sedentary so bad? Izzie Clarke spoke to Paddy Dempsey from Cambridge University...

Izzie - James Brown kinda hit the nail on the head. Get up off of that thing! And when it comes to sedentary behavior, getting up from that thing - whether it's a chair, sofa, or any other of your favorite seats for that fact is good for you. General moving or walking will do the trick, but in true James Brown style, I guess you could also dance till you feel better. And even if you exercise regularly, spending too much time sat down can be bad for you.

Paddy - I do a lot of research on sedentary behavior, physical activity, and its implications for diabetes and cardiovascular disease.

Izzie - That's Paddy Dempsey from the MRC Medical Research Institute in Cambridge.

Paddy - If we break down sitting to its actual behavior in terms of posture and not burning very many calories, basically when we sit throughout the day we're not contracting our muscles and when we're not contracting muscles, there's no metabolic demand on our body. And so that means it's going to be less blood flow to those muscles and all those things in combination; so low blood flow, low demand for energy means our bodies aren't really working as efficiently as I should be in a metabolic sense. And over the long term this can cause problems for our health. The opposite of sitting is being physically active and when you're being physically active you're basically stressing various bodily systems and in doing so they adapt in a positive way for our health. And basically everything we do that's good for us by being physically active sitting kind of does the opposite.

Izzie - Oh dear... We also talk about being physically active also helps your brain as well. Does sitting have an impact on the brain?

Paddy - We do know that physical activity can boost your mood, sharpen your focus, reduce your stress, improve your sleep. And it makes sense that spending a lot of time being inactive and sitting a lot would do the opposite of that. And in a number of our clinical trials that we've run we have seen anecdotally that participants find that at the end of a day where they've been sitting all day they feel more fatigued, more sluggish, less mentally alert. And that's an important point because from a cognitive and productivity point of view, if you're sitting all day and it's affecting your productivity, it's at least an acute reason to be concerned about your mental health in the long term, but I guess also your acute productivity in the workplace.

Izzie - But why does sitting down actually have these negative effects?

Paddy - One way to think about it is: sitting is a bit like turning on your brand new Jaguar or Ferrari and letting it idle all day. It sort of gets all gunked up. Things are gonna go wrong, and that's not too dissimilar to what's going on in our bodies. Blood is pooling, muscles aren't contracting and they're not being used. That notion of use it or lose it as a simple slogan but with profound implications for health

Izzie - The large muscles of the lower body are essentially switched off and the amount of blood circulating slows dramatically. And sticking with the car analogy, our body is a bit like a gearbox. Shifting from neutral (sitting down) straight to fifth gear (the equivalent of a high intensity workout) is difficult. It's easier if we work through the gears and build up how much we move about. Say: how can we do that without the marathon-esque training?

Paddy - I guess you could break it down in terms of what your day looks like. So you get up in the morning, you might eat breakfast and then you've got to get to work and depending on your context you may (if you're close enough to your workplace) be able to actively commute to work. So if it's a short trip you might be able to try walking or cycling or leaving the car at home. If it's a longer trip you could try walking or cycling part of the way - so leave your car further way and walk the last bit, or jump on the train and get off a stop early. So there's ways to embed activity into your commute.

Izzie - As someone who drives an hour to and from work, Paddy suggested I could simply park my car further away from the office so I get a bit of a walk at the beginning and end of each day. He even had a few tips of how to be more active in the office.

Paddy - One of the most obvious ones is something like a sit/stand desk. The basic thing  there is it gives you the option to stand and sit throughout the day. A few other tips, I suppose, that people find useful are if you drink lots of water you need to go to the toilet more, so they often think “stay hydrated! I'll get a water bottle”, which means now I don't need to leave my desk all day. But going and getting a glass of water is a good trick to keep refilling.

Izzie - Plus those return trips to the bathroom actually counts as being active. You could even travel to the toilets furthest away, if you're feeling really daring.

Paddy - Another really good one in the workplace can be standing or walking meetings, so active meetings. One of the good things about them is they actually tend to be shorter. But at the end of the day it's finding opportunities throughout the day where you can be active.

Izzie - But this all assumes you're in a position to leave your desk or are physically able to walk.

Paddy - There's actually some work out there that shows that fidgeting is beneficial because, again, you’re contracting muscles more regularly than if you were just sitting there, static. There are a lot of chair exercises you can do with your upper body. A study was actually recently done with that particular point in mind, where participants who were unable to actually stand up because they were amputees. And they did upper body grinding, instead of using their legs for a cycle, they used their arms for a cycle, and they found that that was equally as beneficial as doing lower body movements. So there's all sorts of ways, and I think if there were particular functional limitations, a really good idea is to chat to a physio because they'll have all sorts of ideas to work around a certain injury or a certain limitation. And there's always a way.