Monday, February 1, 2016

Do Cyclists (And Perhaps Triathletes) Live Longer?

by Larry Creswell, M.D.

In his column last week, Dr. Bob shared information from some recent studies on the issue of endurance athletes and longevity and offered up some thoughts and conclusions. He’s right. The issue of whether there can be too much of a good thing when it comes to exercise is certainly a hot topic. So, more on that topic!

Three studies reported in the last few weeks captured my eye. The first deals with the general issue of whether regular exercise can prolong one’s life -- and, if so, how much exercise is necessary. The second deals with the issue of whether elite cyclists might also enjoy a longevity benefit of exercise -- or whether there is some harm that comes from extreme levels of exercise or training. The final study aimed to determine if the intensity of endurance exercise might play a role in longevity. All of these studies provide some food for thought.

What’s the Minimum Amount of Exercise Needed to Prolong Longevity?
In this month’s edition of The Lancet, one of the world’s foremost medical journals, Dr. Chi Pang Wen and colleagues from Taiwan report on a very large scale study of Taiwanese adults with the objective to assess the health benefits of different volumes of physical activity. Specifically, they wanted to determine if less than 150 minutes of exercise per week was sufficient to reduce mortality or to extend life expectancy.

The study included a whopping 416,175 adults who were enrolled between 1996 and 2008 and then followed for an average follow-up period of 8.05 years. Based on self-administered questionnaires, the subjects were categorized into one of five groups according to their amount of physical exercise: inactive, or low, medium, high, or very high activity. Compared to the inactive group, the low level of exercise group (who exercised an average of 92 minutes per week) had a 14% reduction in all-cause mortality and a three year longer life expectancy. Moreover, for each additional 15 minutes of exercise beyond a baseline level of 15 minutes per day, there was a further reduction in all-cause mortality of 4%. These findings were true for both men and for women and for subjects regardless of their cardiovascular risk factors.

These results are obviously important from a public health standpoint. With various governments and non-profit organizations advocating guidelines for individuals to promote better health, it’s important to determine the amount of exercise needed. As an example of such guidelines, the American Heart Association (AHA) currently recommends “at least 150 minutes per week of moderate exercise or 75 minutes of vigorous exercise (or a combination of moderate and vigorous activity).” It appears from this new study that a longevity benefit comes with even less exercise than previously thought.

At the other end of the spectrum, we might ask the question: is there a point at which too much exercise is harmful? Perhaps the first inkling that this could be true came from a 1986 study reported in the New England Journal of Medicine>/i> by Dr. Paffenbarger and colleagues at Stanford and Harvard. These investigators examined the physical activity levels and lifestyle choices of more than 16,000 Harvard alumni from 1962 to 1978 and found an interesting relationship between physical activity and death rates. For individuals exercising from 500 to 3,500 kcal per week, there was a steady decline in the death rate as the amount of exercise increased, but surprisingly there was a modest increase in the death rate for those exercising more than 3,500 kcal per week.

There have been a good number of reports since then about this issue. I reviewed some of the recently available information in my previous column, “Can Too Much Exercise Harm the Heart?”. Suffice it to say, this issue is not settled. We’re still left with the question of whether endurance athletics at the elite level, and/or over the long term, is harmful -- and, if so, exactly how and why.

Do Elite Endurance Athletes Live Longer?
Just in time for this year’s Tour de France, a group of investigators from the Physiology Department at the University of Valencia, Spain reported a study entitled, “Increased Average Longevity among the ‘Tour de France’ Cyclists.” In a rather simple study, they gathered information about 834 riders (465 from France, 196 from Italy, and 173 from Belgium) who rode in the Tour between the years of 1930 and 1964. The authors found that there was a 17% increased longevity for these riders (81.5 years versus 73.5 years) compared to the (age-controlled) general pooled populations of France, Italy, and Belgium. Granted, the participants in this study rode during a much earlier era, but it is encouraging that this group of endurance athletes didn’t suffer from a reduced life expectancy despite many years of endurance training.

The best review of the world’s available data about endurance athletes and longevity was written last year in the Journal of Science and Medicine in Sport by Masaur Teramoto and Timothy Bungum from the University of Las Vegas. There is credible evidence for improved longevity in athletes in endurance sports (skiing, long-distance running, cross-country skiing), mixed sports (soccer, ice hockey, basketball, track and field jumpers, short- and middle-distance running, and hurdling), and power sports (U.S. major league baseball, U.S. professional football, weight-lifting). It’s important to note, however, that for power athletes in particular, there have been conflicting reports.

Which is More Important for Longevity: Duration or Intensity of Exercise?
The last of the new studies to share comes from Dr. Peter Schnohr and his colleagues in Copenhagen, Denmark, and was reported at last week’s European Society of Cardiology Congress 2011. These investigators reported on Danish cyclists of varying abilities, dividing the athletes into those with typically slow, average, or fast workout intensity, but found that those in the fast, or high-intensity, group enjoyed the greatest longevity. Interestingly, there was no difference in longevity that could be attributed to differences in the duration of training for groups who typically exercised less than 30 minutes, 30 to 60 minutes, or more than 60 minutes per day. These investigators concluded that workout intensity was more important than workout duration when it came to longevity.

In total, I’m chalking these three new studies up to good news for most multi-sport enthusiasts. As little as 90 minutes of exercise per week might improve your life-expectancy. On the far end of the spectrum, it appears that even Tour de France riders -- with many, many years of endurance training -- seem to enjoy a survival benefit over their countrymen. This should provide some reassurance that the typical triathlete isn’t over-doing it when it comes to his heart health. And lastly, there’s now at least some evidence that greater workout intensity might provide a long-term benefit.


Larry Creswell, M.D., is a cardiac surgeon and Associate Professor of Surgery at the University of Mississippi Medical Center in Jackson, Mississippi. In addition to his regular column on Endurance Corner, he maintains The Athlete's Heart blog to offer information about athletes and heart disease in an informal way and to encourage exchange and discussion that will help athletes build a heart-healthier lifestyle. You can contact him at lcreswell@umc.edu.
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