There’s a new study, called the Million Women Study, that says that strenuous exercise is bad for you if you do too much of it. I’m never sure what to think of this kind of thing. And the reporting never sends quite the right message. The Wall Street Journal headline reads: “Couch Potatoes Rejoice: Strenuous Exercise May Be Unhealthy.”
Note that it says “may,” meaning it’s not necessarily unhealthy. So it might be a bit early for non-exercisers actually to rejoice.
According to this report:
A recent study in Circulation, a journal of the American Heart Association, found that exercising strenuously four to seven days a week conferred an increased risk of vascular disease, compared with two to three days a week of strenuous exercise. Accompanying the study, published in Circulation’s Feb. 24 edition, is an editorial entitled, “Physical Activity: Can There Be Too Much of a Good Thing?”
I’m not sure it’s even surprising that you can overdo physical activity. Every reasonable fitness program, from marathon training to resistance programs, have rest days built into each week, rest weeks built into each month.
So I take issue with the opening of the article, in which they say, “As an endurance-athletics mantra, ‘more is better’ can make for speedier finishes. But does it come at the cost of health?” I know endurance athletes like to add more. But smart training often urges less, or at least a mix of strenuous and less strenuous activity.
One popular training book, Run Less, Run Faster, promotes the idea of just three challenging runs per week with some cross training mixed in to round out the program. In the latest clinic I did with the Running Room, we didn’t do all-out training every time we went out. We did a combination that included some tempo runs, some speed work, and a long, slow, distance run every Sunday where we didn’t push the pace at all (though we did push distance).
So that’s not four to seven days a week. Here’s what they report:
Previous alarm-raising research was focused on relatively modest-sized groups of people doing large amounts of physical activity. But this new study comes from an examination of 1.1 million British women over a period of about a decade, and what it measures isn’t exercise so much as rest.
Called the Million Women Study, it tracked for nine years the vascular health of subjects recruited via Britain’s National Health Service. Starting out, the women, ranging in age from 50 to 64, completed surveys about how often they exercised and how strenuously.
Like nearly all physical-activity studies, this research found that exercisers experienced dramatically fewer adverse vascular events compared with non-exercisers. But for those involved in strenuous exercise–defined as “any work or exercise causing sweating or a fast heartbeat”—that advantage disappeared after two or three sessions a week.
Instead of doing better, women who engaged in tough training more than four times a week suffered increased vascular trouble:
At four to seven strenuous sessions a week, the exercisers experienced an uptick in adverse vascular effects, the study found. For women doing any kind of exercise, including gardening and housework, four to six days a week was optimal. Seven days was associated with a rise in vascular troubles.
An especially surprising finding involved venous thromboembolism, typically involving blood clots in the legs. That condition is deeply associated with inactivity, and sure enough, it more often struck subjects who didn’t exercise than those who did. But women engaged in daily strenuous exercise suffered more episodes of venous thromboembolism than did those who exercised rarely or not at all. “That’s kind of shocking,” said O’Keefe.
The Wall Street Journal article is pretty sure no one is going to change their behaviour after learning of this study:
The study likely won’t change people’s behavior. Couch potatoes will take comfort from its suggestion that rest days are beneficial. And daily exercisers, if not large in number, are passionate in the belief that physical activity confers inexhaustible benefits.
But I want to take issue with their assumptions. The study is definitely not encouraging anyone to be “a couch potato.” Nor is it encouraging anyone to go overboard, engaging in vigorous activity seven days a week. But there’s a range of engagement between nothing and every day. There are also various intensities at which a person can work out.
As I said at the outset, I don’t think it’s a huge surprise that we can overdo it with exercise, pushing our physical limits without also getting adequate rest. But the antidote to that is not to rest all the time.
The upshot is about as bland as under-steeped tea: aiming for moderation is good for our health. Doing too little or too much isn’t.