Most of us luxuriate in the warm glow we experience on a run and after. Ah, the calm, the relaxation. There’s nothing like instant gratification. “Running never fails me” has become a popular aphorism.
We also appreciate the dozens of other health benefits associated with regular physical activity such as running. Sure, we sometimes wonder about “excessive exercise.” Is there a limit? After all, there’s a J-curve associated with many health behaviors. A little sun is a good thing. A lot of sun, not so much. Same with pasta. Same with aspirin.
Could a J-curve apply to physical activity and heart disease? Not according to a massive and objectively-controlled new study of 90,000-plus adults from the United Kingdom. It’s the biggest and most precise research of its kind.
New Research on Exercise and Cardiovascular Health
The authors investigated the link between individual activity levels and the subsequent development of cardiovascular disease (CVD, including heart disease and stroke.) They found that the more you move, the lower your risk of CVD. The potential payoff is substantial — from 30 to 60 percent.
Participants were enrolled in the project in their early 60s and followed up for an average of just over five years. The team did not observe any sign of an excessive-exercise effect, noting: “We saw no evidence of higher risk in those engaging in high levels of physical activity, including vigorous [exercise].”
Prior studies of a similar kind, including this meta-analysis, had uncovered a much smaller CVD benefit among subjects who performed regular physical activity — only about 20 percent. You might wonder why the new paper yielded a bigger payoff. Answer: Because it’s a higher-quality paper, making use of modern accelerometer technology (think Fitbits) to measure the daily activities of subjects.
The Problem With Earlier Research
Earlier research gathered exercise data by asking subjects to complete questionnaires. Such self-reports are suspect. Who isn’t going to fib a little and overstate their exercise habits? That’s simply what happens; human nature.
Such questionnaires lead to an underestimation of exercise’s benefits. Think about it. Someone who typically walks a mile a day (20 minutes) will write down 30 minutes on the questionnaire. That’s a 50 percent exaggeration, and it screws up the research results. The database holds a 30, but the reality is 20. Your body knows the difference, of course, and only gives you 20 minutes worth of benefit — a lesser amount than the written data shows.
As a result, any study that can accurately assess your activity level should produce more impressive results than the old studies. That’s exactly what happened with the new paper published in Public Library Of Science/Medicine (free full-text). As the authors observed, “The inverse association that we found is much stronger than that reported from questionnaire-based studies.”
Results: All Movement is Good
The paper tracked moderate activity, vigorous activity, and total activity, finding little difference between the three. In other words, all movement is good. Also, the results were largely the same for men and women.
One small wrinkle: Women appeared to benefit more from vigorous activity than men did. This has also been noted in several other reports, though no one can explain it, or even be confident of its existence. But it can’t hurt to do the occasional fartlek session.
The activity and CVD data were extracted from an impressive health dataset called the U.K. Biobank that has led to many big epidemiological reports in recent years. It enrolled more than 500,000 participants during 2006-2010, and contains a range of medical information on subjects: size, diet, blood pressure, cholesterol, and more, as well as followup diseases.
The paper did not log subjects’ miles of running or minutes of soccer play, or other leisure-time activities (bicycling, swimming, etc). Rather it measured the tick-tock of the wrist accelerometers they wore while washing the dishes, taking out the garbage, walking the dog, and chasing the kids around the house.
Exercise scientists have come to believe that this total activity is as important as distinct “bouts” of exercise. Movement is powerful. Stillness is bad. Subjects in the Biobank study averaged just over 100 minutes per day of moderate activity, according to their accelerometers.
“This is the largest ever study of exquisite device-measured physical activity,” said one of the authors, Aiden Doherty, from the University of Oxford. “It shows that physical activity is probably even more important than we previously thought.”