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The New Exercise Study
A new study has changed the exercise advice that I give to my patients at the clinic. So the standard recommendations are to get at least 150 minutes a week of moderate intensity exercise or 75 minutes of vigorous activity per week. So this assumes that vigorous exercise is about twice as effective as moderate exercise. But a new study completely blows this assumption out of the water and it's got some really important implications for how we approach exercise to maximize our health.
The new study draws on data from the massive UK Biobank, which collected comprehensive health and lifestyle data of over half a million participants. The study authors looked at information about activity levels and health outcomes for a subset of this group. So their goal was to see how the impacts of light, moderate, and vigorous physical activity compare. So they wondered if it's really true that 1 minute of vigorous activity had the same effect as 2 minutes of moderate activity.
In the past, this would have been really difficult to answer because previous studies explored links between exercise and health that typically relied on self-reported data, where participants would answer questions about the exercise. So that method is fraught with potential bias, meaning that we haven't had much confidence in the results. But this new study draws on a novel kind of data to fill in the picture in a way that we haven't been able to do in the past. So a portion of the participants from the UK Biobank wore devices, like a smartwatch for instance, that measured and recorded activity levels. So that gives us access to way more accurate data.
So what did the researchers discover when they sifted through this new data? Well, shockingly, vigorous physical activity wasn't found to have double the impact of moderate physical activity. Instead, it had four to nine times the impact. So there's a range here, because the relationship between exercise and the health benefits varied depending on which health outcome we were looking at. For all-cause mortality it was 4.1 minutes. For heart disease related mortality it was 7.8, and the highest number was 9.4 for type 2 diabetes.
In this study, it also looked at something important that's been much less talked about: light intensity activity like leisure walking. Here you'd expect that would need a much greater volume to see the same impact as 1 minute of vigorous activity. The researchers found that it ranged from 53 minutes for all-cause mortality to a whopping 94 minutes for type 2 diabetes risk. So just think about that for a moment. The data shows that it takes almost 10 times as much moderate activity to see the same benefits as 1 minute of vigorous physical activity when it comes to the risk of developing type 2 diabetes. And if we stick to light physical activity, we would need about 100 times as much.
So the implications here are massive. The standard advice says that 75 minutes of vigorous activity is about as helpful as 150 minutes of moderate activity, and that looks way off. If this study is right, we're going to need at least 300 minutes of moderate activity to gain the same benefits for all-cause mortality compared to vigorous physical activity. But practically speaking, what does all of this mean in terms of the exercise advice that I give to my patients? Well, this is best explained if I give you two patient examples.
Patient Example: Simon (short on time)
So, we'll start with Simon. Simon is short on time, so he wants to know the minimum amount of exercise he should do and still get most of the benefits of exercise. Well, a separate recent study has changed our understanding. In the past, studies generally focused on structured exercise. In other words, they tended to measure activity levels like going for a walk or lifting weights and so forth. The reason is that we're much better at accurately recalling that activity when it comes to that form. So if I ask you, for instance, how much exercise you got in the past week, it's those types of activities that will come to mind.
But we can often engage in physical activity that isn't structured in that way. For instance, you might go up and down stairs in your home several times a day, and maybe you recently carried several heavy boxes to the trash and raked the grass clippings in your yard. For me, jumping on the trampoline with my kids is something that I wouldn't necessarily think to count as exercise. And it's those types of activities that are really hard to recall. So they've also been difficult to measure and include in the different studies so far. Again, this is where smart trackers have completely revolutionized how we can track this activity.
The Concept of VILPA
Researchers recently took advantage of that data to make a startling discovery. Again, we're looking at the UK Biobank cohort, but this time they focused their attention on non-exercisers. These were people who reported no leisure time exercise and no more than one recreational walk per week. Even though they didn't participate in structured exercise, researchers were curious about their physical activity throughout the week. In particular, they looked at how often they performed vigorous activity as they went about their daily life. They called this type of activity vigorous intermittent lifestyle physical activity, or VILPA. They then analyzed the levels of VILPA and how they were associated with all-cause, heart disease, and cancer mortality. It's this type of exercise that would be invisible to traditional study methods.
Here's what they discovered. Let's start with the median number of times a person engaged in VILPA per day. This is the amount of activity where half of the people in the sample are doing more and half are doing less. The median was about three bouts of activity a day, lasting between 1 to 2 minutes each. Remember, these people are non-exercisers. So this is all of the vigorous activity that they're going to get in a typical week, and it amounts to about 6 minutes a day at most.
Compared to those that had no VILPA, the median frequency was associated with an incredible 38 to 40% reduction in all-cause and cancer mortality risk. There was a 48 to 49% reduction in heart disease mortality risk. At a minimum daily total time of VILPA of 3.4 to 4.1 minutes, researchers found an average mortality risk drop of 22 to 28%. The study showed that exercise has a strong dose response that fades the more of it that we get. In other words, the first chunk of exercise appears to be more beneficial than the second, the second is more beneficial than the third, and so on, until we reach a point where it makes little difference.
Have a look at this chart from the study. When we go from no bouts of VILPA to one bout a day, the mortality risk drops sharply. But by the time we go to four to five, the drop is barely perceptible. This tells us that simply going from a sedentary lifestyle to a little bit of activity captures a large chunk of the benefits that we get from exercise in terms of mortality risk. So someone who works in a little bit of VILPA and someone who exercises regularly are both going to see massive gains compared to someone who is totally inactive.
Exercise Snacks
For Simon, since he's short on time, I encourage him to focus on exercise snacks. For instance, walk up one to three flights of stairs instead of taking the elevator. Other examples of exercise snacks are things like push-ups. I'll do a set of push-ups or wall squats during my breaks when I'm in between patients at the clinic. So I can easily do one to two minute bouts of activity three to five times a day at the clinic. And again, on clinic days, I don't necessarily have the time to head to the gym. By pursuing the strategy of consistency, I can reap the lion's share of the benefits of exercise. That's the strategy I suggest to Simon as well, again, since he's so short on time.
But in the future, if Simon can dedicate some time to exercise, I encourage him to focus on vigorous forms. Done safely, that will give him the most bang for the buck, as we saw with the new study we reviewed at the beginning of the video.
Patient Example: Henry (heaps of time)
Then there's Henry, another patient at the clinic. He's at a point in life where he's got heaps of time to exercise. So what advice should I give him? The research that we've been looking at makes one thing clear: vigorous physical activity is far superior to moderate or light activity in terms of its payoff. So I'd advise Henry not to do more than two high-intensity workouts per week. Instead, I'd advise Henry to add in some zone 2 training.
Zone 2 Training
Zone 2 training is when we're working out at an intensity where we can still carry on a conversation. So how much more does it make sense to add? One long-term cohort study found measurable health impacts from getting up to 600 minutes of moderate activity per week. So if Henry really did have that much time to dedicate to his fitness, adding in lots of zone 2 training would be required, in addition, of course, to resistance training and power training.
But back to the point I want to emphasize in this video: we can do a lot of good for our health even at much lower volumes of exercise, particularly when it's high intensity. All of us can add exercise snacks to our schedule no matter how busy we are. Coming back to zone 2 training, it's been a trending topic among health influencers. It's touted as a form of exercise with unique benefits. So, are you really missing out if you're not doing it? In the next video, I break down some recent research that provides some critical context.
Bottom Line
Vigorous activity, even in short bouts, appears to deliver substantially greater health benefits per minute than moderate or light activity, and everyday intermittent bursts of vigorous movement may matter more than many people assume.