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Recent research is helping to debunk myths and misunderstandings about exercise

Recent studies “have advanced our understanding and offer new insights” into the importance of physical fitness and the kinds of physical activity that are most likely to promote a healthy heart, a trio of cardiologists write.

The idea that physical exertion is harmful can be traced back (at least) to the ancient Greek legend of Pheidippides, whose long-distance run in 490 BCE inspired the modern marathon.
REUTERS/John Kolesidis

President Trump reportedly believes in the Victorian-era myth that engaging in exercise is unwise and can lead to early death because the human body is like a battery, with a finite amount of energy.

The opposite, of course, is true. Being consistently physically active is probably the very best thing we can do to ensure a long and healthy life.  And far from draining us of energy, regular exercise gives us more of it.

It’s unclear where Trump picked up that particular mistaken belief. But as Minnesota cardiologists Dr. Steven Bradley and Dr. Michael Miedema point out in a recent editorial in JAMA Network Open, the idea that physical exertion is harmful can be traced back (at least) to the ancient Greek legend of Pheidippides, whose long-distance run in 490 BCE inspired the modern marathon.

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“Some would believe the story of poor Pheidippides is a cautionary tale about the hazards of exercise,” they write, along with their co-author Dr. Erin Michos of Johns Hopkins University in Baltimore. “His battery was drained after running 25 miles to convey the outcome of the Battle of Marathon — his finite supply of energy was used up, and he died as a result.”

“What’s forgotten,” they add, “is that Pheidippides ran 300 miles in the days preceding his final marathon dash.”

“Yes, a sudden increase in vigorous exercise results in a small and transient increase in cardiovascular risk,” the doctors acknowledge. “However, most individuals need to worry about exercising too little rather than too much.”

The editorial goes on to discuss a half dozen studies published in JAMA Network Open within the past 12 months that “have advanced our understanding and offer new insights” into the importance of physical fitness and the kinds of physical activity that are most likely to promote a healthy heart.

Here are quick summaries of some the studies described in the editorial and the outdated ideas about exercise that they have helped to dispel:

  • As important as not smoking

Not smoking is frequently cited as the key thing people can do to avoid bad health outcomes. No doubt about it: Smoking is a major health hazard. But, as Bradley, Miedema and Michos point out, “increasingly, it is recognized that the association of aerobic fitness with health outcomes is just as strong, and potentially stronger” than not smoking.

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The evidence: In a large study published in JAMA Open Network late last year, people who were the least aerobically fit were five times more likely to die within a period of about eight years than people who were the most aerobically fit. In comparison, the risk of early death during those eight years for smokers was 41 percent higher than for non-smokers.

  • No need to fear ‘elite’ levels of fitness

There’s been some concern that the extreme exertion engaged in by elite athletes (such as those who participate in Ironman triathlons) may put the heart at risk for a sudden catastrophic event (the “Pheidippides  syndrome”). New research indicates, however, that such worries are unfounded.

The evidence: The same study that found the benefits of exercise to be potentially greater than not smoking also found no association between high levels of aerobic fitness and early death — a finding that suggests “no ceiling or untoward effects are associated with elite fitness,” write Bradley, Miedema and Michos.

  • Low-intensity activity offers benefits, too

You don’t have to be an elite athlete to benefit from exercise. Even light-intensity physical activity — such as a taking a leisurely walk or doing household chores — can improve health outcomes.

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The evidence: Researchers reported in a March JAMA Network Open study that doing light physical activity was associated with a lower risk of heart attack or stroke in older women. Each additional hour spent daily in such activity lowered the risk by 10 percent.

  • It’s never too late to get active

It’s always best to exercise regularly throughout your life. But the idea that the negative health effects of a lifetime of sedentary behavior can’t be overcome by taking up exercise late in life has been upended by recent research.

The evidence: A large U.S. study, published in JAMA Network Open in March, found that people who were sedentary during early adulthood but who then took up regular physical activity later in adulthood (between the ages of 40 and 66) were a third less likely to die prematurely than their peers who stayed inactive.

  • Aerobics more important than muscle strengthening

Having strong muscles is often a marker of physical fitness. But does it contribute much to cardiovascular fitness? Perhaps indirectly, but not anywhere near as much as aerobic fitness, according to new research.

The evidence: A study published earlier this month in JAMA Network Open found that although “muscular training is an important component in maintaining or improving function among patients with long-term diseases and in the later years of life,” aerobic fitness is a much greater contributor to a healthy heart.

  • Measuring fitness can be simple

How to best measure and assess cardiovascular fitness has been a matter of debate. Recent research suggests, however, that it needn’t be complicated. In fact, the measurement tool can be as simple as asking people to do some push-ups.

The evidence: A JAMA Network Open study published last February found that male firefighters who could complete more than 40 push-ups per minute were 96 percent less likely to develop heart disease over the next 10 years than their peers who could only 10 or less during that same time period.

“That finding is “a good reminder of the simple assessments that can lead to a better understanding of exercise tolerance and associated health outcomes,” write Bradley, Miedema and Michos.

FMI: You can read the editorial in full on the JAMA Network Open website.