Marathon training improves heart health
If one of your New Year’s resolutions was to take up running, apart from toned muscles and a narrower waistline, you might also be able to look forward to taking up to 4 years off the age of your blood vessels too! Chris spoke to Charlotte Manisty, a cardiologist at UCL and Barts Health about her recent work in the Journal of American College of Cardiology...
Charlotte - We were interested in whether participants who are planning on running the London marathon could reverse the effects of aging. We know that with age your blood vessels get stiffer and that leads to increased blood pressure but also leads to increased risk of dementia, stroke, heart failure, kidney problems, etc.
Chris - So who did you recruit and how did you measure them?
Charlotte - We took participants who'd been accepted through the ballot for the London marathon and we recruited anybody who had no preexisting history of cardiovascular problems and also who was relatively untrained. So participants that were exercising for less than two hours per week, embarking on a marathon for the first time. And we were looking at the effects of that training on their cardiovascular system.
Chris - Any particular age range or was it all comers?
Charlotte - We recruited participants of all ages, so the mean age across our study was 37 but there was quite a broad age range from 21 to 69 years and fairly reflective of the general population who are completing the London marathon.
Chris - And how did you work out how stiff their blood vessels were?
Charlotte - Well, we were interested in looking at the stiffness of the aorta, so the main blood vessel leading away from the heart, using MRI, so magnetic resonance imaging. And what we were interested in is looking at the speed of blood through the blood vessels and also looking at the distensibility or the elastance of the blood vessels so that we could look at whether exercise has a positive impact on the cardiovascular system.
Chris - So every time the heart beats the blood vessels stretch a bit, you're able to see that with an MRI scanner and that gives you a marker for how stretchy a person's aorta is. And you're asking "if I compare the measurements I make before they start training with what happens once they've successfully completed the marathon, is there a difference?" And what did you find? Does it make a difference?
Charlotte - Yeah. What we found was an improvement in the elastance when they train for the London marathon over that six month period. And that change actually equates to a four year reduction in vascular age. So it appears that you can actually reverse the stiffening effects that you get with aging by exercise training. What we also saw in participants was that they got a reduction in their blood pressure of about four millimeters of mercury. It's actually not far off equivalent of most first line blood pressure medications, and we know that that kind of difference in blood pressure, if sustained over a period of time, results in about a 10% reduction in stroke risk. So really the potential health benefits, if the changes that we see are sustained, is really quite significant.
Chris - And do the people critically have to keep up with the exercise regime to keep their four years of reversed blood vessel aging? Or if they then gave up after completing the marathon would their blood vessels remain four years younger than they should be?
Charlotte - Yeah. Now that's the crucial question and actually one that we haven't yet got the data to answer. We don't know whether the effects are sustained longterm, whether you continue to get incremental benefits if you increase your exercise, or if you sustain your exercise for longer periods of time. The other thing that we don't know and we would be interested in knowing is whether if you take patients who have got increased blood pressure at baseline, whether they get different effects. What our data suggests in healthy volunteers without blood pressure problems, is that it seems to be those that have greatest to gain, that have the biggest benefits. So if you are older, if you're male, if you're less fit, if you've got slightly increased blood pressure baseline, those are the patients that seem to derive the greatest benefit from the exercise training.
Chris - And do you know how it works?
Charlotte - It's a bit unclear. We know that some of this will be related to blood pressure, but what we can see is that there's actually changes beyond the differences in blood pressure. And this may be changes in the smooth muscle cells within the aorta. It may be due to neuro-hormonal effects. It's difficult to say. And we don't actually have the basic science data to support the mechanisms behind this. And certainly this is an area that's ripe for more research.
Chris - So is everyone in your research group now a runner? Are you doing the marathon?
Charlotte - Um, embarrassingly no! I have not done the marathon. I think people have definitely developed an awareness and certainly the first author on the paper, my PhD student is now running the marathon this year having not done previously. So certainly we are all more aware of it than we might otherwise have been.