Best time of day to exercise?

Norman Swan: Tegan, when do you take your exercise?

Tegan Taylor: I am definitely a morning exerciser. I mean, I do exercise at night sometimes, I’ll go to a weight session at night because that’s when it’s on. But if I was left to my own devices, I would absolutely be exercising at the crack of dawn, it’s my preferred time of day. 

Norman Swan: So here’s the second question; are you a morning person or a night person? 

Tegan Taylor: I’m a morning person. What about you? 

Norman Swan: I’m probably more of a night person. 

Tegan Taylor: When are you an exerciser? 

Norman Swan: I tend to do it in the morning, because if I leave it to the end of the day, I don’t get it done. 

Tegan Taylor: This is it. This is it. So there’s scheduling issues, and then there’s also, like, your chronotype. Anyway, let’s get into it, because that is what we are talking about today on What’s That Rash?.

Norman Swan: The podcast where we answer the health questions that everyone’s asking. 

Tegan Taylor: So this week’s question comes from Helen, saying, ‘Hello, I really enjoy your program and its sister,’ by which I’m sure she means the Health Report. Helen says, ‘My husband has recently come across information suggesting that exercising in the morning, especially without some gentle movement first, significantly increases the risk of heart attack or stroke over 60.’ Helen says, ‘Is there good evidence to support this? More broadly, is there a least dangerous time or a more beneficial time? What are the main considerations for best time of day, level of fitness, age, and awake time, i.e. night-owl or lark?’ Norman, I thought this was just going to be about, like, when do you exercise? I didn’t realise that people were maybe dying for choosing the wrong time of day.

Norman Swan: Well, let’s talk about dying first, since that’s what Helen’s worried about for her husband, maybe even for herself. There is no question that taking exercise reduces the risk of sudden cardiac death, without any question of doubt. If you’ve got a background risk of a sudden cardiac death and you exercise regularly, your risk of that drops, your risk of a heart attack drops, and your risk of a stroke drops. 

On the other side of it (and it doesn’t outweigh the benefit of exercise) there is an effect on the risk of sudden cardiac death, on time of day, of exercise time of day, and it’s thought to be a problem of blood pressure. So if you’ve got cardiac risk factors, and we’ve all got cardiac risk factors, even though we might think we don’t, which is plaque, atherosclerosis in our arteries, but what’s thought to happen in terms of time of day is that in the morning as you get up out of bed, your blood pressure has a spike, and that spike is exaggerated if you then take exercise, and if you’ve got soft plaque in your arteries, that burst of blood pressure can open up the plaque and cause a heart attack. That’s the theory behind morning exercise. And when you look at the epidemiology of heart attacks, they more often than not occur in the morning. They don’t exclusively occur in the morning, but they more often than not occur in the morning.

Tegan Taylor: You’re really making a strong case for hitting that snooze button, Norman. If I’m already in my bed and I’m, like, I don’t want to get up and go for a run, it’s because I might die of a heart attack if I do.

Norman Swan: So, here’s the good news. And the good news comes from a massive study that you and I have spoken about before, which is called the UK Biobank Study. This is where 500,000 people or thereabouts have been incredibly altruistic and agreed to have their health monitored, a lot of knowledge about their health and well-being recorded, their genes measured, and their medical records followed through time. And international researchers have been using this database, because it’s almost unique worldwide, and learned a lot from it. 

So they’ve looked at this very question about the risk of death, morning, midday or night, in terms of exercise, and they’re able to compare it to the risk of coronary heart disease, and indeed their chronotype. Are they a morning person or a night person? The results were fascinating. There was indeed a morning spike…

Tegan Taylor: Of heart attack?

Norman Swan: They were looking at sudden cardiac death. So yeah, there was a morning spike. But there was also an evening spike as well. So it wasn’t that it was exclusive to the morning, it was that people who exercised in the evening also had a small risk of sudden cardiac death. And remember, I just can’t say this often enough, overall people who exercise had a lower risk of sudden cardiac death. So coronary risk factors did make a difference. So if you had risk factors for coronary heart disease, your risk of sudden cardiac death went up, which is what you’d expect. But your chronotype mattered.

Tegan Taylor: So chronotype being are you a night-owl, are you an early bird, are you somewhere in between. We have talked about this before, there’s a previous What’s That Rash? on night-owls and early birds.

Norman Swan: So it turns out that if you are a morning person and you exercise in the morning, according to the UK Biobank Study, there’s no increased risk of sudden cardiac death. If you are an evening person and you exercise in the evening, there’s no significantly increased risk of sudden cardiac death.

Tegan Taylor: So it was when people were fighting their nature.

Norman Swan: Correct. So, if you’re a night person and you exercise in the morning, then you had a slightly increased risk of sudden cardiac death. They were the ones who got it, again at a lower level than you would expect, because they were exercising. And vice versa. There was a lower spike in the evening, but it tended to be people who were morning people and exercising in the evening.

Tegan Taylor: That is wild and a great excuse to get out of going exercising early in the morning with your early-bird friend if you don’t want to. Can we just put some numbers around what the increased risk was? Because I think that this is a sort of thing that’s, like, ‘Headline! More likely to die if you’re a night-owl and you exercise in the morning!’ What actual absolute risk are we talking about here?

Norman Swan: So just to give you a perspective here, out of all the biobank sample, they looked at 94,489 people. Overall, during a follow up of seven years, there were 629 sudden cardiac deaths. 

Tegan Taylor: Is that a lot? It sounds like a lot, but it’s not really a big proportion. 

Norman Swan: No, so it’s fewer than 100 a year out of 94,000. And what they don’t talk about here is what’s called the absolute risk. So in other words, if I am an evening person and I exercise in the morning, what’s my personal increased risk? And they didn’t actually do that, but you’re asking the right question because you want to know what the increased risk is for me myself.

Tegan Taylor: For example, if your absolute risk was 1%, it maybe went up to 1.5%.

Norman Swan: Correct. 

Tegan Taylor: Hopefully that puts Helen’s mind at ease, at least a little bit, in terms of the risk of getting out of bed and going for an exercise at all. So can we talk a bit about her subsequent questions which are really, like, is there a best time of day to exercise? What do we know about this?

Norman Swan: The best time to exercise is the time that you actually can exercise.

Tegan Taylor: Well, that’s like what you were saying, right? Like, you exercise in the morning, because if you don’t do it, then it might not happen.

Norman Swan: Yeah, early morning and late in the evening…the way the paper puts it is those are less favourable times to exercise. But, you know, if you’re going in tune with your body, the risk is really low.

Tegan Taylor: And I think it’s worth calling out here that nearly half, 46% of Australian adults don’t meet the Physical Activity Guidelines, which are, like you said, Norman, one of the biggest ways that we can protect against coronary heart disease.

Norman Swan: And one of the ways you do that, you think, well, I’ve got to start bashing the pavement and doing fast jogging and so on…if you’re going from…the reason why it’s safe is that it’s moderate exercise. And if you’ve not had any exercise for a long time and you’re getting off the couch to do exercise, walking for 30 or 40 minutes along the flat will be moderate exercise. You’ll get out of breath, and that will be you getting out of breath. Nobody’s saying to you that you get off the couch and you run. You walk, and you walk fast enough along the flat that you’re getting out of breath. And don’t be embarrassed that you’re getting out of breath walking along the flat, because two weeks later you won’t be out of breath, which means you’ve got to add in a hill, or you’ve got to walk faster so that you are out of breath. So this progression which you need to do, it happens slowly and steadily, and your body adjusts, it’s not sudden. There are well documented sudden cardiac deaths where you play tennis once a week, and that’s the only exercise you get, or squash, and suddenly from a sitting start you go and you do this extreme exercise which is going to raise your blood pressure and your pulse acutely when you’re not fit. That’s not good for you.

Tegan Taylor: So time of day in general, and so we’re not worried so much about having sudden cardiac death. We very much hope that that does not happen to us, but we are wanting to optimise our exercise and working in the time of day with that. I mean, for starters, exercise is a really important part of our body clocks and it’s a zeitgeber, it gives us time in our brain and our body.

Norman Swan: That’s right. And if you’re an evening person, it might be quite good for you to get up in the morning, and maybe you get this small adjustment, which means you’re sparking away and not falling asleep in front of the telly as easily.

Tegan Taylor: So what about performance? Are there certain times of day that we are maybe more likely to…you know, if you were in a competition, that that would give you an advantage?

Norman Swan: The evidence is all over the place with that, although, as you would imagine, in elite sports they’ve got some greater understanding. So in sports where you require accuracy, such as tennis and so on, you are probably better in the morning, that your accuracy is higher in the morning…

Tegan Taylor: Because you’re more mentally sharp?

Norman Swan: Yeah, but there are plenty of sports where you’re a bit better off in the afternoon. But I think these are marginal changes, and the reality is if you qualify for Wimbledon, you’ll just take what you get.

Tegan Taylor: I thought I’d heard before that your muscle performance is better in the evening, like if you’re wanting to do weight training.

Norman Swan: I think there’s some truth to that, yes, I think what changes in the morning is the skill base, rather than the power base or the aerobic base.

Tegan Taylor: So that’s lifting weights. What if you’re trying to shed weight?

Norman Swan: Well, you’d think that physics applies here, you know, calories in, calories out. It turns out that studies of weight loss suggest that morning exercise is better for weight loss. Now, this may well be because it changes your appetite during the day, that you’re not feeling as hungry for breakfast and you delay your eating…

Tegan Taylor: What, from exercising in the morning? If I exercise in the morning, I am ravenous for the rest of the day.

Norman Swan: I have to say, I cycle into work, and when I get into work I just need something, it’s true. But there is quite good evidence that morning exercise helps you control your weight. 

Tegan Taylor: Well, there you go.

Norman Swan: And the other thing in all this is people who exercise are not necessarily the same kind of people as people who don’t exercise, and people who exercise at different times of day aren’t the same. And what we didn’t talk about in this UK Biobank Study, which I said earlier, is that the group that exercised in the middle of the day were less likely to be employed, more likely to be retired, so there was a different profile for people who are exercising at different times of day. And you’d think that you’re actually going to be more likely, if you’re a retiree and exercising at midday, to have a sudden cardiac death, but that wasn’t the case.

Tegan Taylor: But maybe you’ve also got enough time to make yourself a nice salad for lunch and get enough sleep at night, maybe you’re not quite as stressed. There are so many different things that might feed into your overall health.

Norman Swan: Don’t get me onto retirement, that’s another What’s That Rash?.

Tegan Taylor: Oh, now I’m really intrigued. Is it good for you or bad for you? Just give me like a top line. 

Norman Swan: Don’t retire. 

Tegan Taylor: That’s why you’re still working at the ripe old age of…55?

Norman Swan: No, 55 is down the track a bit.

Tegan Taylor: Of course, sorry, my mistake, 50, 51? 51. But yeah, two bottom lines. One, if I’m worried about a heart attack, what do I do? And two, is there an optimum time of the day to exercise for my health?

Norman Swan: So the answer to the first one is if you’re worried, everybody should know their cardiac risk factors, even from your 20s and 30s, once in that decade, each decade you should know what your blood pressure is, you should know what your cholesterol levels are, so that you can actually do something about them, even if it’s a lifestyle change. And sometimes you’ll find very high levels, which means you need medications, and that will be life saving. So know what your coronary risk factors are, and if they’re raised, do something about them, which doesn’t necessarily always mean drugs.

Tegan Taylor: In conjunction with your doctor and not solely based on the information you hear on a podcast.

Norman Swan: Exactly. And secondly, time of day. Just take exercise the time of day where you can take exercise and take it easy, build it up. 

Tegan Taylor: What did you do today, Norman?

Norman Swan: Cycled into work. 

Tegan Taylor: I haven’t done my exercise yet, but I’m thinking of going for a swim tonight. 

Norman Swan: Good. 

Tegan Taylor: Well, thank you so much, Helen, for the question. You can email us your questions at thatrash@abc.net.au, we love having a go at answering them. Maybe you will be the person that asks us about retirement so Norman can unpack his answer that he gave me before.

Norman Swan: And we’ve had some feedback on acupuncture and dry needling.

Tegan Taylor: Yes. So we had this email from Chris about acupuncture. Chris was very sceptical of it, because they tried it as low back pain treatment, didn’t really work. However, Chris has an n-of-one involving Chris’s dog. She was a German Shepherd, had a dreadful issue of hip dysplasia and spinal pain. 

‘We reached the point where the vet advised we could do no more, apart from lots of drugs. Anyway, a friend suggested acupuncture at that stage. BJ the dog had to be lifted into the car, and her back end swayed like a drunken sailor, frequently giving out. Well, we arrived at the acupuncturist, he said he could help, putting needles all along her spine and her back legs and paws, leaving them in for about half an hour. She looked like a hedgehog, but she took it out without any sign of complaint or discomfort.’ 

Chris writes, ‘Once removed, she stood up, shook herself, and walked steadily out of the room, and, to my shock, jumped back into the four-wheel drive. She was like a new dog. No way she could have been influenced by the hype around it. So it convinced me that acupuncture works for…’ Well, Chris says ‘some people’. Maybe you should have said ‘some creatures, some beings’.

Norman Swan: Some human and non-human animals. Well, that’s true, it’s hard to describe a placebo effect to a dog. So, well done, I’m glad that BJ is back on her feet.

Tegan Taylor: Me too. Thank you so much, Chris. As always, you can email your questions, comments, feedback, dog stories to thatrash@abc.net.au.

Norman Swan: See you next week. 

Tegan Taylor: See you then.