Sunday, October 19, 2008

Phun Physiology: The Young at Heart, by Dean Furbish

The conversation in the parking lot at the conclusion of Saturday’s “Showdown in Black Creek” Permanent was delightfully animated (see Mike D's previous post). I mention this because we’d spent the day under overcast, melatonin skies and had battled a slight inbound headwind. No dreary moods here, though. The group of nine riders engaged in mild banter, self deprecation, and story-telling over coffee, pastry, and post-ride picture posing. It can be said that these riders are literally some of the young at heart. Read on.

The topic of this post occurred to me when a couple of riders shared hilarious anecdotes about how their normally slow heart rates had raised eyebrows during annual health checkups. Slow heart rates aside, it’s a fact that endurance training makes hearts young.

One indication of a “young” heart is its ability to metabolize glucose as an energy source during exercise. An aged heart loses its ability to utilize glucose during exercise. The good news is that endurance exercise reverses this aspect of aging.

Moreover, exercise benefits even the elderly, including those who previously have led inactive lives.

Exercise turns aged hearts into “young” hearts metabolically, according to a recent study out of Washington University School of Medicine in St. Louis, because it reverses the aged heart’s inability to metabolize glucose during exercise. In fact, exercise training enables the hearts of older people to double their glucose utilization during high-energy-demand exercise just like the hearts of younger people.

Women’s hearts benefit doubly metabolically as the result of endurance training. In addition to increasing cardiac glucose metabolism, it turns out that cardiac fatty acid metabolism increases as well in women. The same cannot be said for men.

I include some of the specifics of the 11-month study to point out that people do not need to be randonneurs or RAAM types or even train for years in order to obtain this anti-aging heart benefit of regular exercise.

In fact, endurance training was defined in the Washington University study as hour-long exercise sessions 3-5 times per week consisting of walking, running, or cycling. Participants began at 65% of maximum capacity for three months increasing to 75% for the next eight months. The six men and six women in the study were between the ages of 60 and 75. Although they were non-obese, participants had previously lived inactive lives.
Phun physiology advice: Keep riding!

The reference is here: Soto PF, Herrero P, Schechtman KB, Waggoner AD, Baumstark JM, Ehsani AA, Gropler RJ. Exercise training impacts myocardial metabolism of older individuals in a gender-specific manner. American Journal of Physiology. Heart and Circulatory Physiology. June 20, 2008 (advance online publication).

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