Ask the Doctors

Dear Doctor: I'm a middle-aged guy, and I thought my health was fine. But I just got diagnosed with pre-diabetes, so I've started hitting the gym pretty hard -- cardio five days a week, strength-training three days a week. Now I read that all this activity can raise my risk of a heart attack. What gives?

Dear Reader: It's been several decades since the "feel the burn" exhortations of scores of fitness programs first started to seep into the American consciousness. If a moderate amount of physical activity was good, the thinking went, then more -- a lot more -- just had to be better. But when a group of researchers recently looked at data from 25 years' worth of exercise patterns in about 3,000 men and women enrolled in a long-term study about heart health, they uncovered surprising trends.

Individuals who logged 7.5 hours or more of strenuous exercise per week were 27 percent more likely to develop a buildup of calcium and plaque in the arteries of their hearts by the time they reached middle age than were the more moderate exercisers. When the data was broken out by gender, the results were even more startling. White men had an 85 percent higher risk than did their less active peers of developing arterial calcification in their later years. This in turn translated to a rate of heart disease that was double that of the more moderate exercisers. And to add one more unexpected twist, these patterns didn't apply to the black men in the study.

The higher levels of coronary artery calcification, often shortened to CAC, suggested that the more intense approach to exercise resulted in damaging stress to the arteries. More extreme exercise, both in effort and duration, has been shown to invoke an inflammatory response in the body. With everything we're now learning about potential dangers of chronic inflammation, we look forward to future studies, which may shed light on this connection.

When it comes to your own exercise routine, we land on the side of moderation. We think that by becoming active, you've made a good start at addressing the conditions that put you on the road to pre-diabetes. (And before we get to specifics, we're going to put in a plug for you to please take a clear-eyed look at your diet as well.)

Current guidelines recommend 150 minutes per week -- that's 2.5 hours -- of moderate physical activity. In the most general sense, that's any sustained activity performed at a pace where holding a conversation is possible but not easy. If you prefer a more rigorous workout, such as running, then the intensity goes up but the time spent drops to 75 minutes per week. That's a workout where yes, you can say a phrase or two, but a conversation is out of the question. In addition, weight-bearing exercises that target all of the major muscle groups -- that's the legs, hips, back, abdomen, chest, shoulders and arms -- should be done twice a week.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

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