fitness · health · training

Is Strenuous Exercise “Bad” for You?

three women running on a trailThere’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.

13 thoughts on “Is Strenuous Exercise “Bad” for You?

  1. WSJ adores this storyline for some reason — maybe James O’Keefe (the chief promoter of this view) has friends there. Anyway, here is the study:

    As is common in huge studies, we have exercise data gathered by questionnaire and recall, not measurement. So to start, ‘defined as “any work or exercise causing sweating or a fast heartbeat”’ could mean almost anything, depending on the frame of reference for “sweating” and “fast heartbeat.”

    Alex Hutchinson over at Runner’s World has a part-time job actually reading and assessing these reports, and to read his write-up of this one it sounds like a completely different study. He makes the important point that the issue looks like recovery ability. (The WSJ sort of gets at that, but not really.)

    If you take the study results to heart, the figures suggest you’d be good with 6 days a week instead of 7. (Of course, elite and recreational competitive athletes also have key, personal motivations that have zip to do with optimizing health outcomes.) Note that the recommendations, such as they are, boil down to “up to moderate, up to 6 days a week is helpful; strenuous 2-3 times a week is helpful” — which is suspiciously similar to pretty much every well-designed training program.

    1. Thanks for that. You’re right about their weak definition of “strenuous” too. I appreciate the link to the RW write-up.

  2. It’s so frustrating that the media is making it seem like a person’s only fitness options are “couch potato” or “extreme athlete” 😛

  3. I’m ex Army and it was all or nothing before, but now later in life with diabetes etc i find that a good balance is better than a good beasting. With a beasting the pain would be there, but with a good long term balance more can be done, as well as keeping the motivation up for it. In my opinion.

  4. Hmmm, I really think the extreme athletic training, meaning hard long runs or bike rides nearly every day …for several years.. with no gentler ride or run in between or just stopping, is what the concern might be.

    We do need to give our bodies a break after 1-2 consecutive days of hard workout for several hrs. The body needs to repair itself and restore energy reserves. It’s not driving oneself hard or just resting, when one has a cold, flu or is injured, etc.

    And I mean cycling 100 km. every day for 2 months solid. But surely a person will not die if you are trained for it and do it once in your life. Not for several years.

    I’ve gone through various summers, where I was cycling every day for 100+ days with no bike rest in between. It’s not hard since I’m car-free. These rides are a few km. to 80 kms. during the day. After stopping for 1 super rainy/very windy day, one realizes, the body DOES need a break.

    But I say: a person does build up critical muscle memory which becomes important to faster recovery after a major injury.

    I mounted my bike and cycled a few km. for lst time after 3 months of head injury recovery this year. Believe me, I wondered if I could bike at all. So it wasn’t even couch potato slackness…it was momentary fear.

    Got over it. 🙂 May we not lose that exercise fear for a very long time.

  5. Reading junk articles about the dangers of exercise are bad for me. They raise my stress level due to righteous indignation and frustration over the stupidity of it all. But after I run a few miles I feel better.

  6. Reblogged this on FIT IS A FEMINIST ISSUE and commented:

    This throwback Thursday urges us to be cautious about fitness research headlines like “Couch Potatoes Rejoice!: Strenuous Exercise May Be Bad for Us.” Punchline: moderation is probably the way to go….

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