What is the minimum exercise we can do to improve our health?
How much exercise can I really manage to do?
That was the question asked by journalist James Gallagher, presenter of the program InsideHealth (Internal Health) of BBC Radio 4. To answer it, he underwent a series of scientific tests and spoke with several experts.
The result of his experiment was encouraging, especially for those, like him, who don’t have much time and perhaps really want to exercise formally every week.
What follows is his first-person testimony.
In a parallel universe: I practically live by the pool, bike everywhere, and do 10K runs just for fun.
But in the real world: I work, have a family, and am a caregiver, so my weekly visit to the pool feels like quite an accomplishment.
Although it’s recommended to get about two and a half hours (150 minutes) of moderate-intensity exercise each week, about a quarter of the population does not even exercise for half an hour.
So is there something easier we can aspire to? What is the least amount of exercise that could improve our health?
If anyone wants to make exercise advice less intimidating, it’s Dr. Zoe Saynor, an assistant professor of clinical exercise physiology at the University of Portsmouth who is also a retired elite rugby player.
She’s going to help me find an answer. To achieve this I agreed to wear an activity tracker for a week.
The results were terrifying. I managed just one minute of vigorous exercise (equivalent to running) every day and 16 minutes of moderate exercise (sort of like a brisk walk)
“That’s an image we see over and over again in many people living in modern society,” says Saynor.
So whatever state my body is in is going to depend in large part on that one hour swim I do most weekends.
Go faster or go further?
If I want to spend less time exercising, but still achieve high results, then the only option is to work harder.
“There is clear evidence that if you want to do shorter exercise sessions, they need to be higher intensity,” says Saynor.
In the official guide, the alternative to doing 150 minutes of moderate activity is to do 75 minutes of intense activity.
High-intensity interval training (HIIT), which involves short but high-intensity bouts of activity, gets a lot of attention.
However, Dr. Saynor says that most people can’t stick with it because HIIT requires exercise at very vigorous levels.
What is the minimum acceptable?
When it comes to the minimum amount of exercise that people should get, Dr. Saynor is a firm believer of 5,000 to 6,000 steps per day.
And while it’s easy to scoff at tips like getting off the bus one stop early or taking a walk during your lunch hour, it seems like they can make all the difference.
A study of almost 80,000 people published in the specialized magazine JAMA internal medicine (JAMA Internal Medicine) showed that walking a little more each day reduced the risk of cancer, cardiovascular disease, or early death.
That pattern continues until you hit about 10,000 steps a day, but then again, faster steps are worth more than slow ones.
“If you don’t have time to suddenly do 10,000 steps a day, can you then do 5,000 faster? That would show an improvement in your health,” says Saynor.
You don’t even need to do formal exercise like going for a run, going to the gym, or swimming to see a noticeable health benefit.
A study published in the journal nature medicine (Natural Medicine), analyzed 25,000 people who did not formally “exercise”, but did engage in small, intense bouts of activity in daily life.
These are activities that might seem unremarkable: running to a train, pushing the vacuum cleaner, playing with children or dogs, carrying heavy groceries, or climbing the stairs.
Research showed that doing three to four minutes of short bursts of vigorous activity throughout the day had a profound health benefit.
“People who do this intermittent activity can reduce the risk of major diseases like heart failure and cancer by up to 50%,” Mark Hamer, professor of sports and exercise medicine at University College London, tells me.
“Over the last decade, the guidelines have slowly moved away from the 30-plus-minute-a-day message toward the ‘anything counts’ message, and I think these results support that message,” he adds.
Dive into the water and get fit?
If time is still short to achieve this, there may be another way that also sounds much nicer.
How about a bath, a jacuzzi or a sauna?
I put on my favorite bathing shorts and plunged into some kind of pool of very hot water.
This is a precisely controlled experiment, so I couldn’t just jump into the water. Researcher Thomas James had to drag me into a pool of 40 degree Celsius water so that only my head and neck were above the water.
The key thing is that 40 degrees is higher than my core body temperature (37 degrees Celsius), so the whole time I was there my body was working hard to lose heat.
Very quickly I could feel sweat pouring down my forehead, but the rest of my body was just wet and not refreshing.
“Hot water is particularly lethal in this regard,” James explains.
If I spent too much time in there, I would overheat and die of heat stroke. My heart was pumping harder and faster as I tried to lose heat by bringing the blood closer to the surface of my skin.
“Your heart will be working hard, similar to what you would see with light-intensity exercise,” he says.
“We are seeing reductions in blood pressure, even in healthy people.”
The big idea is to improve exercise.
“This is a very good way to mimic some of the benefits you get from exercise, but the evidence is pretty clear that exercise is best and that the two together have greater health benefits,” says James, adding : “I think this will really play a big role in the future.”
So if you go to the gym and then go to the sauna or jacuzzi, you might get a great result.
However, the Portsmouth team cautions people to follow the recommendations.
“Don’t say, ‘I’ll stay here as long as I can.'” Do it to enjoy it,” says James.
The recommendation is usually between 10 and 20 minutes, depending on the type of facility, so it is very important to check beforehand.
Obviously, we should all try to get the recommended amount of exercise, but since that’s impossible for many of us, it’s very comforting to know that significant benefits can be gained simply by doing a little more than we already do.
The program InsideHealth is produced by Erika Wright.
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