The extensive health benefits of an active lifestyle

If it were a pill, exercise would be very big business indeed...
05 December 2023

Interview with 

Scott Lear, Simon Fraser University


Woman running in the sunset


So what are the implications of doing fewer than the recommended 150 minutes of moderate to vigorous physical activity a week? And what does exercise actually do for our health? Well, quite a lot as it turns out. Chris also spoke with Scott Lear, Professor in Health Sciences at Simon Fraser University in Vancouver, and author of the ‘Become Your Healthiest You’ blog. He recently conducted a study into the effects of vigorous physical activity on health outcomes…

Scott - Vigorous physical activity is a type of activity where you might find your heart rate going up and your breathing rate going up. If you're able to carry on a conversation while you're walking or going on a jog, that's what we consider moderate, but with vigorous activity you wouldn't be able to carry on a conversation while doing that activity.

Chris - And does it have to be in those sorts of realms to be beneficial?

Scott - Definitely not. Any activity is better than no activity. We know that the benefits start from the very first step somebody does, whether it's activity or exercise, and the very first minute. The more steps, the more minutes, the more games, the more swimming strokes, the chances for getting diseases like heart disease, cancer, and early death go down the more you are active.

Chris - Do you know by how much? And how are you studying this to try and work out the degree of impact?

Scott - So when we look at these outcomes of disease and early death, we do what we'd call an observational study where we ask people how much they're exercising and then we'll keep studying them for maybe 5, 10, 15 plus years. We look at, is there a difference in who got heart disease based on whether they were active or not, or how much? And we find that people who are more active may have as much as a 20% reduction or protection from early death or getting disease in that 10 year study period compared to those people who are either less active or not active at all.

Chris - How do you control for the fact that people who are more likely to indulge in that sort of activity might be more likely to look after their body, eat a healthy diet, drink less, not smoke? How do we make sure that it's not their lifestyle around the fact, but they're also more motivated to exercise?

Scott - Excellent point. And there's also the consideration that people who might have an illness or a disease but not yet know about it are in the study and that may be why they're not exercising. These are important points. What we would do statistically, basically the analysis would say, well, if everybody was on the same diet, if everybody wasn't smoking, if everybody had the same body weight, this is the effect of exercise. Now, it's not foolproof. So when we do these observational studies where we're just following people and seeing how their exercise relates to their health, we look at multiple studies together and look at a consistency of effect. We also have intervention studies where we take people and exercise them and compare them to a similar group of people and don't exercise them. We see other health parameters improve: reduced body fat, reduced blood pressure, reduced blood glucose, lower chances of getting diabetes.

Chris - So a big reduction, isn't it? If that was a pill, we'd call it a wonder drug. Does the beneficial effect of exercise always apply irrespective of age or are there different forms or formats of exercise that benefit different people at different ages?

Scott - I would say, to the first question, exercise benefits anybody at any age. So if somebody's not exercising, the best time to start doing it is right now, today. It doesn't matter if that person's 70 years old and never exercised for 50 years or even in their life. It's always a good time to start. The benefit somebody gets is relative. If we picture, let's say, that 70-year-old person who's not active and spends a lot of time sitting down, even doing simple things like leg raises or getting up and down out of the chair will improve that person's fitness. Whereas, for somebody who's younger, up and about, that type of exercise isn't going to be a challenge so it's not necessarily going to improve their health. In order to get the benefits from activity and exercise, it needs to challenge the body. That's always relative to what the person is doing, currently. The Olympic athlete has to do a lot more than I need to do in order to improve their fitness.

Chris - The effects aren't just restricted to physical gains, though, are they? Because people who exercise also say they get a big mental boost from this. And indeed, people like Perry Bartlett in Australia showed a number of decades ago that, in fact, it changes the way brain cells, newborn nerve cells in the brain, are born and survive if you exercise more. So it seems to have a very broad range of effects.

Scott - Yes. And I would say that effect that you're touching on right now is why people actually exercise. I can talk about all the long-term health benefits 5, 10, 20 years from now and I know, when I exercise, it's improving my health, but I do it because I enjoy it. I am not thinking, "Oh, this is reducing my risk for cancer by 20%, 10 years from now." I'm thinking, "I feel good doing it, I feel good afterwards." It's that mental benefit that actually is what keeps people exercising.

Chris - Feels awful at the time though, doesn't it? I know only too well.

Scott - Alright. I'm not going to disagree with how you might feel when you're exercising. These are subjective when we ask people, and I can attest to this: if I do moderate versus vigorous activity, I feel better doing the moderate activity at the time than the vigorous activity at the time but, afterwards, it's flipped. This is even when we have people do two different types of exercise, that moderate, lower, less intensity, then the vigorous, higher intensity, they will say, as you point out, the vigorous activity is less comfortable, but they report greater improvements in mood and happiness in the hours following the vigorous activity, more so than those who did the moderate type of activity.


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