Everyone knows that physical activity offers many physical and emotional health benefits. But new research finds that not exercising can do more damage to your well-being than smoking, diabetes, or heart disease.

In a study published October 19, 2018, in the journal JAMA Network Open, researchers reviewed data from exercise treadmill testing (ETT) conducted at the Cleveland Clinic in Ohio. They studied 122,007 patients who underwent ETT, or cardiovascular stress testing, between January 1991 and December 2014.

The tests were done as part of regular checkups or for heart and lung assessments on men and women ranging in age from 18 to 80-plus years.

Based on the test results, researchers divided data on the patients’ cardiorespiratory fitness into five categories or performance groups: elite, high, above average, below average, and low.

"We were particularly interested in the relationship between extremely high fitness and mortality" says lead author Kyle Mandsager, MD, an electrophysiology fellow at the Cleveland Clinic. "This relationship has never been looked at using objectively measured fitness, and on such a large scale."

Clinical Risk Factors for Mortality

According to the researchers, “the increase in all-cause mortality associated with reduced cardiorespiratory fitness … was comparable to or greater than traditional clinical risk factors,” including coronary artery disease, smoking, and diabetes.

“The more time you are able to spend on a treadmill stress test, [the more it] is similar to the effect that you get from reducing risk factors,” says Wael Jaber, MD, a cardiologist at the Cleveland Clinic and the senior author of the study. “If you treat somebody for hypertension, for example, or high cholesterol, you’d expect a certain reduction in mortality."

Other key findings of the study included:

• Increased heart and lung fitness was directly associated with living longer lives.
  

• There were no negative effects as aerobic exercise increased.
  

• Extreme aerobic fitness was associated with the greatest benefit, especially in patients over 70 and in patients with high blood pressure.
  

Can You Exercise Too Much?

The researchers said they were surprised to find that extreme levels of exercise did not have any negative consequences. "We found in our study there is no limit to how much exercise is too much," says Dr. Jaber.

The results contrast with some previous research, such as one study published in January 2012 in The New England Journal of Medicine, which suggested that there could be a risk, albeit low, of cardiac arrest associated with participating in long-distance races.

Jaber says that people who lead sedentary lifestyles and want to start exercising, or physically active individuals who want to boost their exercise regimen, should work with their physician to develop an “exercise prescription” that’s right for them.

Guidelines on Physical Activity

According to the most recent physical activity guidelines, published in 2008 by the Department of Health and Human Services:

• Adults should do at least 150 minutes a week of moderate-intensity, or 75 minutes a week of vigorous-intensity aerobic physical activity, or an equivalent combination.
  

• For more extensive health benefits, adults should increase aerobic physical activity to 300 minutes a week of moderate-intensity, or 150 minutes a week of vigorous-intensity aerobic physical activity, or an equivalent combination.
  

• Older adults should be as physically active as their abilities and conditions allow.
  

• Children and adolescents should do 60 minutes or more of physical activity daily.
  

However, a National Health Statistics Report published June 28, 2018, found that only 22.9 percent of U.S. adults ages 18 to 64 met the guidelines for both aerobic and muscle-strengthening activities between the years 2010 and 2015.

Getting and Sticking With the Program

It’s never too late to benefit from physical activity, says Nieca Goldberg, MD, a cardiologist and medical director of the Joan H. Tisch Center for Women's Health at NYU Langone Medical Center in New York City.

“Even if you aren't fit, if you start exercising and stick with the program, you can lower your risk of heart disease and improve survival,” says Dr. Goldberg.

David Sagbir, MD, a cardiologist in Columbus, Ohio, acknowledges that it isn’t easy to get started on a physical activity program. In 2005, Dr. Sagbir started a free program called “Walk with a Doc,” in which healthcare providers join members of the community on walks in cities across the country.

“If you tell the doctor who’s leading the group that you want to exercise even harder, first they’ll say thank you, and then they’ll be glad to work with you,” says Sagbir.