From The Desk Of Clarence Bass
Can You Be Too Fit? Study Says “No”
Top Treadmill Times Associated with Lowest Mortality
Overdoing a Good Thing
Concerned about new evidence suggesting a connection between extreme exercise and atrial fibrillation and other maladies (see my piece on the dangers of unrelenting training: ) researchers led by Wael Jaber, MD, a cardiologist at the Cleveland Clinic, assessed the association of fitness levels and mortality.
It is well established that fitness is correlated with life expectancy; fit people are healthier and live longer than unfit people. Nevertheless, it has been suggested that the benefits of exercise may plateau and reverse at upper levels.
The Cleveland Clinic group took it a step further “identifying patients with extremely high cardiorespiratory fitness (2 or more standard deviations above the mean for age and sex) to evaluate the relative benefit or harm of extreme CRF compared to more modest levels of aerobic fitness.”
The strengths of the study are the large number of patients and the use of maximum effort treadmill tests to measure fitness. A weakness is that patients were only tested once.
The study included 122,007 consecutive patients referred to the Cleveland Clinic for treadmill testing from January 1, 1991, to December 31, 2014, with a median followed-up of 8.4 years. Deaths during that period totaled 13,637.
Patients were grouped by age and sex-matched fitness into 5 performance groups: low (up to 25th percentile), below average (25th to 49th percentile), above average (50th-74th percentile), high (75th to 97.6th percentile), and elite (at or above 97.7th percentile).
The key finding is that “fitness was inversely associated with all-cause mortality without an observed upper limit of benefit.”
Extremely high aerobic fitness was associated with the lowest risk-adjusted all-cause mortality. Achieving and maintaining very high levels of aerobic fitness was found to be particularly important in patients 70 and older, when mortality rates typically rise.
No evidence of a plateau or U-shaped association was found. Fitness becomes more important with age.
The “surprise” Dr. Jaber told CNN was that a sedentary lifestyle is worse for your health than smoking, diabetes or heart disease. “If you compare the risk of sitting versus the highest performing on the exercise test, the risk is three times higher than smoking,” Jaber continued. “There’s no age limit that doesn’t benefit from being physically fit.”
For patients, especially those who live a sedentary lifestyle, Jaber said, “You should demand a prescription from your doctor for exercise.”
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All well and good, wonderful in fact. The case for exercise continues to grow. Exercise is indeed the best medicine.
This study shows that you can become very fit at any age without causing harm; that appears to be beyond dispute.
My best time on the treadmill at the Cooper Clinic put me two and a half minutes above the 99th percentile for men my age.
I did this mainly by weight training and foothill workouts mimicking the treadmill protocol once or twice a week.
Photo by Justin Joseph
But it does not defuse the dangers of extreme and unwise training regimens.
The researchers address this issue in the “Discussion” portion of the study:
There continues to be uncertainty regarding the relative benefit or potential risk of extreme levels of exercise and fitness. Significant attention has been paid to better understand the long-term cardiovascular effects of extreme exercise. Potentially adverse cardiovascular findings in highly active cohorts, including an increased incidence of atrial fibrillation, coronary artery calcification, myocardial fibrosis, and aortic dilation, have raised concern for potential cardiovascular risk above a certain exercise or training threshold. It remains unclear whether these associations are signals of true pathologic findings or rather benign features of cardiovascular adaptation. The present study is the first, to our knowledge, to specifically evaluate the association between extremely high CRF and long-term mortality.
The entire study can be read online:
My brother-in-law killed himself running. He dropped dead without warning—at 54. Heredity was probably a factor, but I believe extreme running was the primary factor. He was a streaker, running every day for years. Not a jogger, he ran hard, often for miles up hill.
That’s the kind of extreme, unrelenting exercise that causes harm. The body needs time to recharge after exercise. Without rest, the body eventually rebels, shuts down.
For many years Kenneth Cooper told the world that vigorous exercise was the solution to our health problems. He began to have doubts about the benefits of extreme exercise in 1984, when his 52-year-old friend Jim Fixx, the author of The Complete Book of Running, dropped dead of a heart attack while running. Unwilling to concede, he linked Fixx’s death to hereditary factors.
Eventually the evidence became so voluminous—he claimed to know 150 cases, including notables such as cardiologist and running philosopher George Sheehan, who came down with cancer or other serious illnesses—that he conceded that too much exercise can kill you.
Dr. Cooper has long said that people running more than 15 miles a week are doing it for reasons other than health.
More recently (June 25, 2015), The Cooper Institute published a comprehensive and thoughtful piece by Steve Farrell, PhD, FACSM, titled “How Much of a Good Thing Is Too Much.”
Two factors caught my eye about the possible mechanisms by which too much exercise might be harmful. The first is that markers of cardiac damage appear in the blood of about 50% of participants during and following a marathon race. The changes are temporary and revert to normal within a few days. Something similar appears following a strength training session. Once again, values usually revert to normal within two or three day. That tells me that rest is important after vigorous exercise. Go hard one day and then go easy for a few days is a good plan.
Streakers obviously don’t get the message.
Dr. Farrell ended with several points of emphasis. The first two apply to those of us interested in healthy living:
1: There is strong agreement among health professionals that for the overwhelming majority of the population, the benefits of regular aerobic exercise greatly outweigh any potential risk. 2: The number of Americans who do not meet the minimal public health guidelines for aerobic exercise is exponentially greater than the number of Americans who might be doing too much aerobic exercise. While significantly exceeding the upper end of the public health guidelines is obviously necessary to compete at a high level in endurance events, it does not seem to result in further health benefits as compared to staying within the guidelines. As I have heard Dr. Kenneth Cooper state many times over the past two decades, if you’re running more than 15-20 miles a week, you’re doing it for reasons other than to achieve good health.”
You can read the entire article online:
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It is well documented that unrelenting endurance exercise can be harmful, especially for those in their middle years and older. I began this article with a link to a piece about The Haywire Heart, an authoritative book on the subject of endurance sports and heart health. The main message is that athletic excellence and age can be a toxic combination. A reduction in training frequency or length often fixes the problem, defusing the connection between exercise and heart damage.
The need for rest and recovery increases with age. Athletes in their 50s and 60s are especially susceptible to the dangers of overtraining. The few of us still training hard into our 70s and beyond are breaking new ground. We must listen to our body and train sensibly.
Train hard and rest hard seems to be the best approach—at any age. If you’re going to err, do it on the side of active rest.
It lends credence to my once a week lifting and aerobic training; weights on day 1 and aerobics on day 5, allowing four days recovery after weights and three after aerobics. Both workouts are short and hard.
You'll find many more details by following the link at the beginning of this article.
January 1, 2019
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