My neighbor Ed was a thin man all his life. He maintained an ideal body weight by combining regular physical activity with a modest intake of calories. He was a “young” seventy year-old who looked the picture of heart health.
Ed regularly read the newspaper while walking on his treadmill, he hit a golf ball straighter and longer than his peers, and he wore the same size jeans now than he did in college 50 years ago. What’s more, he bragged about his low blood pressure, normal cholesterol level and perfect blood chemistries. He took no pills. I think he went to his primary care doctor each year just to show off his health.
The morning he woke with crushing chest pressure and shortness of air stunned him. “This couldn’t be a heart attack?” he thought. An hour later, minutes after his urgent heart catheterization showed severe blockages in all three of the main coronary arteries, a sternal saw provided a heart surgeon access to his dying heart.
Ed did well. The story had a happy ending. He still looks the picture of health, but now there’s a scar on his chest and a few pill bottles in his medicine cabinet.
How can a human who exudes heart health go to bed well and wake up with severe heart disease? What’s missing? What could Ed have done differently? Could his doctors have measured anything—over and above the traditional risk measures—that might have suggested his obviously higher cardiac risk?
Regular readers of Cycling Wednesday might think I’m heading down the inflammation road here. Was Ed a hot-headed bike racer? Was he divorced, alone, or, did he stay up all night ruminating about the stagnant stock market?
No. I have never heard Ed holler; he’s married, and goes to bed every night before the local Fox news comes on. He even has a dog.
So what gives?
It turns out that Ed was physically active, but he wasn’t physically fit. There’s a big difference. Ed strolled easily on the treadmill, he played golf, and he kept busy in the yard with regular duties. All this activity burned enough calories to help him maintain a size 34″ waist and good blood chemistries. But Ed never pushed his exercise to a level that produced adaptations of the heart, lungs and blood vessels. He never jacked it–as we bike racers say.
On an objective measure of exercise capacity, one that requires a sustained high heart rate and consistent oxygen uptake from the working muscles, Ed would have looked pedestrian. He could stroll at a ten-minute mile pace for miles, but ask him to run 1 mile at an eight-minute per mile pace and he would have come apart.
Competitive cyclists, runners and swimmers can tell you about the notion of physical fitness. You get fast by going fast for cycles. These jabs of exertion produce adaptations that increase the heart’s ability to pump nutrients and the muscles’ ability to burn the delivered fuel. That’s called fitness. And it doesn’t come by reading on a treadmill or a recumbent bike.
Improving your fitness isn’t just good for getting a shout out at the town’s criterium bike race, or a mention in the local paper’s 5k race results. Though under appreciated by many medical people, how long one can drill it on a treadmill translates as a major predictor of heart health.
This week, in a “published online before print” version of Circulation, a 66,000 patient-strong study from the well known mecca of exercise science, the Cooper Clinic (Dallas, TX), suggested that exercise capacity improved the classification of heart risk, over and above the traditional risk factors (smoking, age, BP, blood sugar and cholesterol). The researchers measured how long each person could sustain exercise on a standard treadmill protocol. (This time correlates well with the standard measure of fitness, the VO2 max.) They then followed these subjects for the next 25 years. Surprisingly, the capacity to exercise resulted in a significant re-classification of some subjects from low to high heart risk. This study appeals to me for four reasons:
- Exercise capacity was easy to measure. All one needs is a stopwatch and a treadmill.
- The time on a treadmill bested the predictive value of other more sexy tests, like the CRP level, for instance.
- Unlike coronary calcium CT-scans, measuring exercise capacity is radiation free and much less expensive.
- Exercise capacity as a metric for predicting heart disease risk is consistent with prior scientific studies: Take this NEJM study which revealed peak exercise capacity to be a stronger predictor of mortality than smoking, diabetes, high blood pressure or an abnormal ECG.
I realize that speaking negatively about regular physical activity while our society is overcome with languidness seems heretical.
Being thin, maintaining a normal blood pressure, and having favorable blood tests, as Ed did, would clearly be an improvement for most citizens of North America. What would be better though, is to exercise vigorously enough to improve your exercise capacity–to become fit.
This means sweating (not reading) on a treadmill or an exercise bike. It means getting out of your comfort zone for periods of time. Sure, it may sound nit-picky, but exercise is like anything else: there are good kinds, better kinds and really dumb (Ironman) kinds.
And…you bet I believe that exercise is something that should not be multi-tasked. Don’t expect me to tweet on the bike.
Go fast. Rest. Be Fit.
P.S. Here’s link to the Balke Test: The treadmill protocol that the Cooper Clinic researchers used to to estimate physical fitness. After an adequate warm-up and clearance from your doctor, you could use this as a simple measure of your exercise progress.
*This blog post was originally published at Dr John M*