Anti-Aging: Can You Exercise Too Much?

By Coach John Hughes

I’m a retired ultracyclist and I specialize in coaching endurance riders. I’m starting to coach a Brit whose goal is to cycle 20,210 km (12,557 mi.) over the course of this year. Last year he rode 15,000 km (9,320 mi.). Another client rode 3,000 miles last year and we’re going to significantly increase her mileage. I’m also in several groups devoted to long distance riding. My clients and the roadies in these groups ride the vast majority of their training and event miles at an endurance pace, with just a bit of intensity. A common question is, “Is riding as much as I do healthy or bad for me?”

Some studies have suggested if the amount you exercise is more than some limit it may be unhealthy.  Other studies suggest heart risks are associated with extreme exercise. This column reports on different studies.

I’m not a medical expert; however, from my review of the literature here are my two personal conclusions:

#1. Exercising as much as the American College of Sports Medicine’s (ACSM) recommendations has great benefits that outweigh any possible health risks. The ACSM recommends that adults aged 18–64 get at least 150 minutes a week of moderate intensity aerobic exercise or 75 minutes a week of vigorous intensity aerobic exercise or an equivalent of the two.

The ACSM adds that there may be further health benefits to doing twice as much, i.e., up to 300 minutes per week of moderate exercise or 150 minutes a week of intensity or a combination. Riding at a conversational pace for 2-1/2 hours a week (the ACSM’s minimum recommendation) at 15 mph works out to about 2,000 miles a year and riding five hours a week is about 4,000 miles a year.

The World Health Organization’s basic recommendations are the same as the ACSM that adults aged 18–64 engage in at least 150 minutes a week of moderate intensity aerobic exercise or 75 minutes a week of vigorous intensity aerobic exercise or an equivalent of the two. The WHO recommends that more exercise is better and estimates that the maximal cardiovascular health benefits are obtained at an exercise volume up to about three to four times the current exercise recommendations.

Riding 7-1/2 hours a week (three times the ACSM’s and WHO’s recommended basic amount) would be about 6,000 miles a year and riding 12-1/2 hours a week (five times the recommended amount) would be about 10,000 miles a year.

#2. Even if riding as much as 10,000 miles a year carries increased health risks the enjoyment factor outweighs the health risks.

You can draw your own conclusions.

Cleveland Clinic

In an article from the Cleveland Clinic Heart Risks Associated with Extreme Exercise cardiologist Tamanna Singh, MD, writes, “Extreme, long-term endurance exercise puts equally extreme demands on the cardiovascular system.” (emphasis added) Dr. Singh continues, “Moderate exercise is still the best prescription for good physical and mental health – and competitive athletes shouldn’t give up their training schedule just yet.”

Let’s delve a little deeper.

The Extreme Exercise Hypothesis

A research paper The “Extreme Exercise Hypothesis”: Recent Findings and Cardiovascular Health Implications by Thijs M.H. Eijsvogels PhD, et. al. says, “Emerging evidence from epidemiological studies and observations in cohorts of endurance athletes suggest that potentially adverse cardiovascular manifestations may occur following high-volume and/or high-intensity long-term exercise training, which may attenuate the health benefits of a physically active lifestyle.”

The research paper is a review of studies on the effects of extreme exercise. The paper notes that, “There are valid concerns that the message that high-volume, high-intensity exercise can potentially harm the heart, may discourage a physically active lifestyle among the general population and contribute to the increasing prevalence of physical inactivity.

The “Extreme Exercise Hypothesis” research paper cites a study of 661,137 individuals, which concluded that, “Risk reduction for all-cause mortality occurred at an exercise volume of three to five times current exercise recommendations.” This supports the WHO and ACSM recommendations

A different study of 130,843 individuals from 17 low- to high-income countries to concluded that individuals in the high physical activity group had a substantially reduced risk for all-cause mortality compared to the low physical activity group. About 112 minutes per week of physical activity yielded the largest risk reductions. Above 255 minutes a week of exercise the significant health benefits were lost. Riding two hours (~112 minutes) a week at 15 mph would be about 1,600 miles a year. Riding 4-1/4 (255 minutes) a week at 15 mph would be about 3,300 miles a year.

The “Extreme Exercise Hypothesis” research paper notes that due to the relatively small number of individuals in the most active groups, it is difficult to determine an upper limit for the benefits of physical activity and that future studies are needed.

Cooper Institute Study

Scientists at the Cooper Institute in Dallas and other institutions conducted a more robust study over 10 years. They looked at the records of 21,758 men, most of them in their 50s. (They plan to include women in a follow-up study.) They categorized the men into groups, based on how much they exercised.

The first group worked out vigorously for at least five hours a week and often more, the equivalent of running six miles a day or riding about 4,000 miles a year. A second group did somewhat less exercise and a third group exercised less than half each week as the most avid exercisers.

The researchers determined that the men in the highest-exercise group tended to have more arterial plaque. The degree of plaque is assessed using a coronary artery calcium score. Someone with a calcium score greater than 100 is considered to have a worrisome calcium buildup. The researchers found the men in the highest-exercise group were about 11 percent more likely to have a calcium score higher than 100, compared to men who moved less. (My calcium score is 80.3; about 70% of the men in my age group have a higher calcium score.)

The researchers then checked death records for a decade or so after each man’s latest physical. Some men had died, particularly from heart attacks among men with calcium scores higher than 100. However, few of those men came from the group that exercised the most. The extreme exercisers turned out to have less risk of dying prematurely than men with the same or higher calcium scores who rarely worked out.

The study concluded that large amounts of exercise may increase the risk of developing plaques and at the same time reduces the likelihood of dying from a heart attack.

The New York Times published an article Can You Get Too Much Exercise? What the Heart Tells Us about the study. The study itself was published in Journal of the American Medical Association on Cardiology.

U.K. Biobank Study

Another large study concluded almost any amount of physical activity appears to be good for cardiovascular health, with no apparent upper limit to the benefits.

Dr. Terence Dwyer, an emeritus professor of epidemiology at the University of Oxford in England, and his colleagues looked at data in the United Kingdom Biobank. Dr. Dwyer and his colleagues looked at the records for more than 90,000 of the men and women in the database who had worn activity trackers for a week. They divided them into four groups, depending on how many minutes, in total, they moved every week, and how much of this activity was moderate, such as walking, or relatively vigorous, like jogging, as verified by their trackers.

The researchers gathered data about which people among the 90,000 volunteers developed heart disease in the years after joining the study. People in the least-active group, who rarely walked around or formally exercised, were more than twice as likely to have heart disease now as the most-active men and women.  The study assumed that annual exercise would be similar to just one week of data.

The researchers also found no upper limit to the benefits. The men and women who moved the most showed no increased risk for heart problems. These individuals walked as much as 1,100 minutes (18-1/3 hours) a week i.e., more than two hours a day (a total that included both exercise and activities of daily living like grocery shopping or doing housework) and also often working out intensely for 50 minutes or more a week. This group enjoyed the greatest risk reductions, with both men and women showing about equal benefits. Riding at 15 mph for 18-1/3 hours a week equals about 14,000 miles a year!

The results “provide even stronger evidence than has been available previously” that “physical activity, including vigorous physical activity, is important for reducing the risk of cardiovascular disease,” Dr. Dwyer says.

This study is associational, showing that active people happen also to be people with healthy hearts. It doesn’t prove that walking and other activities directly strengthen people’s hearts. Dr. Dwyer points out that the number of people who did extremely high amounts of intense activity was small, so it’s possible that long-term, intense exercise might, at some point, stop being good for hearts. This requires more scrutiny, he says.

He says that for most of us increasing our exercise “to much higher levels or more vigorous levels” should substantially reduce our chances for heart disease.

The New York Times published an article about the study Can You Get Too Much Exercise? What the Heart Tells Us. The study was published by PLOS Medicine, a peer-reviewed publisher.

British Bus Conductors Study

We’ve known for decades that exercise is good for your heart. This originated with a study Jeremy Morris, a British epidemiologist. In the late 1940s and early 1950s, he found that British bus conductors who spent their days strolling aisles and climbing steps on the double-decker vehicles, were about half as likely to have a heart attack as the buses’ drivers, who sat all day.

My eBook Anti-Aging: 12 Ways You Can Slow the Aging Processincludes chapters on how to meet the ACSM’s recommendations on aerobic, high intensity aerobic, strength training, weight-bearing exercises, balance and flexibility. I include sample weeks and months for different amounts of exercise. I give you plans to build up to 100 km and 100 mile rides. I include a plan to increase over two years your annual riding from around 4,000 miles (6,500 km) to over 5,000 miles (8,000 km) a year. You can easily modify the plan for different annual amounts of riding.

I discuss the importance of recovery and how to gauge if you are getting enough recovery. I combine the different kinds of training into programs balancing training and recovery. The 106-pageAnti-Aging: 12 Ways You Can Slow the Aging Processis $14.99.

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Coach John Hughes earned coaching certifications from USA Cycling and the National Strength and Conditioning Association. John’s cycling career includes course records in the Boston-Montreal-Boston 1200-km randonnée and the Furnace Creek 508, a Race Across AMerica (RAAM) qualifier. He has ridden solo RAAM twice and is a 5-time finisher of the 1200-km Paris-Brest-Paris. He has written over 40 eBooks and eArticles on cycling training and nutrition, available in RBR’s eBookstore at Coach John Hughes. Click to read John’s full bio.