Every Bit of Exercise Counts

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A paper recently published in the prestigious journal Nature Medicine will revolutionize our approach to exercise. Here’s the executive summary: if health is your goal, then visits to the gym aren’t required.

If this sounds like blasphemy, it may help to recall that humans spent three million years evolving, and for most of this time, gym memberships weren’t a thing. And because gyms weren’t an option, it’s likely that evolution has designed the human body to be adequately, perhaps even optimally, maintained by the normal day-to-day activities of hunter-gatherers.

Or there’s this: the Japanese are the world’s longest-lived people1, but Japan is famed for its lack of gyms.

Or this: Tai Chi is a practice specifically developed to improve health but does not involve machines or sweating.

Maybe it’s time to rethink the whole “gym membership is required for your health” thing.

The title of the Nature Medicine paper is academic, even soporific, and utterly forgettable: Association of wearable device-measured vigorous intermittent lifestyle physical activity with mortality2 Indeed, it’s hard to guess from the title what this paper is even about. But the basic discovery is simple: we’ve been going about exercise all wrong. Or perhaps better put, we’ve been thinking about exercise all wrong.

But it’s not our fault. “Exercise” has been defined by authorities as something like “go to the gym and sweat for an hour or two several times a week”. The minimum requirement set by the CDC is 150 minutes per week of moderate-intense physical activity plus 2 days of muscle strengthening activity”3 That’s a lot of trips to the gym, and really more than most of us with jobs and lives can manage.

But it turns out that like much of other received wisdom (e.g. “wait 30 minutes after lunch before swimming”, “drink 8 glasses of water every day”, etc.) this prescription for hours of moderate-intense activity every week is just wrong. Yes, if you want to run a marathon or compete as a bodybuilder, you’ll need a specialized approach to training. But if your goal is a healthy and long life all that’s really required is adequate activity accrued in any way at all, even just a few minutes at a time. And actually, not even that much activity is required.

As Stamatakis and co-authors point out in their Nature Medicine paper, people who engage in intermittent activity of less than 5 minutes a day distributed throughout the day reap rewards similar to people who were dedicated to conventional exercisers in terms of less cardiovascular disease and less cancer.

Moreover, the “exercise snacks” that break up sitting time need not be intense to substantially reduce levels of both blood glucose and blood pressure. A recent paper4 found that simply walking slowly for one minute every thirty minutes largely reversed the harms caused by passive sitting. Further, we now know that minimal-intensity physical activity (walking) actually improves insulin action and plasma lipids more than vigorous cycling when caloric expenditure was the same.5

It really does seem that our evolutionary heritage makes the hunter-gatherer lifestyle the optimal “health and longevity workout”. This shouldn’t surprise us, of course, but because the exercise industrial complex has dominated the messaging around exercise for so long it feels like heresy to say we can be healthy with way less effort. And no trips to the gym.

So how can we incorporate these insights into our workdays? NPR’s Allison Aubrey recently reported that just breaking up our work day with occasional brief walks would be enough to undo the harms of caused by our addiction to passive sitting6. And this sounds as though it would be easy to implement: just get up occasionally and go for a stroll.

Unfortunately, public health researchers have discovered over the years that they can’t beg, or cajole, or shame people into healthier behaviors. Rather, they must change the environment in a way that makes unhealthy behavior impossible; think divided highways, air bags, or improved air quality.7

How might we “passively” incorporate more movement into peoples’ days which are now spent largely slumped in front of computer screens? One solution would be to make sitting active rather than passive. Because people are constrained to sit many hours each day, simply switching to active chairs might inject enough activity to make us all healthier. The research has yet to be done, but the circumstantial evidence is persuasive that active sitting could be an important public health innovation.

Although this blog is written as a “news flash from the lab”, it’s clear that most of us already know that hours at the gym aren’t paying off. How clear? Well, although 14% of adult Americans have gym memberships, 80% of these folks never go to the gym they are paying for, and of those who do get to the gym a third admit that they never break a sweat. But this isn’t to say that gym memberships don’t have value: 50 percent of gym members in one poll admitted that they only go to the gym to check out the opposite sex or meet friends. And it seems to be working. Another study conducted by Nuffield Health found that 10.5 percent of members actually live with someone they met at the gym.8

Seems gym memberships may add value after all, just not the value that they claim to add.

1List of countries by life expectancy

2Association of wearable device-measured vigorous intermittent lifestyle physical activity with mortality

3How much physical activity do adults need?

4Breaking Up Prolonged Sitting to Improve Cardiometabolic Risk: Dose-Response Analysis of a Randomized Cross-Over Trial

5Minimal Intensity Physical Activity (Standing and Walking) of Longer Duration Improves Insulin Action and Plasma Lipids More than Shorter Periods of Moderate to Vigorous Exercise (Cycling) in Sedentary Subjects When Energy Expenditure Is Comparable

6Sitting all day can be deadly. 5-minute walks can offset harms

7Why a ‘Passive’ Health Approach Can Produce the Most Action - The New York Times

89 Surprising Gym Statistics

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