By Dr. Kate Scannell, Syndicated columnist; First Published in Print: 06/09/2012
Can physical exercise be unhealthy for you?
Throughout my career as a doctor, this question certainly ranks amongst "the top 10" questions ever raised by my patients. Typically, it was asked by patients who, like Mark Twain, had "never taken any exercise except sleeping and resting" and intended to argue against my recommendation for a healthy dose of physical activity.
Everyone, it seemed, could recount a cautionary tale about a friend or family member who had suffered some ungodly accident or illness in the course of exercising. Fatal heart attacks while jogging. Disastrous collisions with automobiles while biking. Asthma flares while swimming and head injuries from diving. A patient once justified abandonment of her walking routine after being pecked by a giant wild turkey. Comedian Red Skelton famously joked that he got his exercise "on the golf course -- when I see my friends collapse, I run for the paramedics."
Because exercise causes chemical and hormonal changes in the body, I always speculated that it could affect different people differently -- sometimes, in a negative manner. After all, people varied in their biochemical responses to other physiologic stimuli like medications or food. But without any credible evidence regarding exercise, how could you say when and if exercise might be harmful?
Well, I suppose all the exercise naysayers feel somewhat vindicated now. A study published May 30 in the online journal PloS found that about 10 percent of people experienced an adverse health effect from exercising. Researchers drew this conclusion after careful analysis of data accumulated from six exercise studies involving about 1,700 people. Overall, for approximately one in 10 people, exercise worsened at least one risk factor for heart disease -- like blood pressure, triglycerides, fasting insulin levels or HDL cholesterol. And, at the heart of the problem, the researchers didn't understand why these differences occurred or which people were more likely to suffer them.
In truth, I'm worried that patients whose only exercise has been pushing their luck will run with this study. I'm concerned that some will jump to the wrong conclusion and misread it as justification for a sedentary lifestyle.
The emergence of the study also likely reinforces the common belief that if you just wait long enough, medical research will ultimately generate a new truth that finally aligns with your lifestyle choices. Many of us patiently await the scientific proof for chocolate curing diabetes. Potato chips preventing cancer. Butter making us smarter. Cupcakes resolving psoriasis.
While the new study reveals information that is not too surprising, it does have the power to startle by virtue of representing the first serious comprehensive effort to examine whether regular exercise might be harmful.
We doctors have been promoting exercise since time immemorial -- yes, throughout many centuries, and before the elliptical bike or Spandex even existed. What took so long for medical research to raise such an obvious question?
We likely would have known more about health consequences of exercise if there existed greater profit-generating opportunities to capitalize on such research. But there's no money to be made in a physician's recommendation that a patient walk 30 minutes each day, while millions of dollars are thrown at research in quest of a new pill to lower cholesterol or reduce weight.
This point is further underscored by a second study published this month that purports to be the first thorough and detailed review of the medical literature concerning cardiac problems associated with excessive endurance training and exercise.
The publication in this month's issue of the Mayo Clinic Proceedings analyzes more than 50 studies following athletes participating in extreme endurance events like long-distance bicycle racing and ultra-marathons. It reveals a significantly higher -- but still, relatively low -- incidence of cardiovascular damage like heart enlargement and scarring, as well as irregular heart rhythms.The study's lead author emphasized that while extreme exercise can be unhealthy, 30 to 60 minutes per day remains healthy and helpful for most people.
From these two new studies we can conclude that the vast majority of people who engage in regular exercise enjoy health benefits without harm, and that serious cardiovascular damage due to extreme endurance exercise remains an exceptional risk. Both studies also remind us that we have been running on unexamined assumptions about exercise and physical activity for too long a time.
Even knowing from the first study that at least one cardiovascular risk factor worsened with exercise for about 10 percent of people still doesn't tell us whether those people actually suffered more heart attacks or shorter lifespans. That's another assumption that urgently needs to be examined.
Meanwhile, we might rest assured that no medical research yet substantiates any cardiovascular benefit from channel-surfing and couch potato-ing. And exercise -- like most inclinations -- can prove harmful when taken to an extreme. We need to find a healthy middle ground on which to exercise good judgment while also learning to hurdle over unhealthy assumptions that throw us off-track.
===============================
Kate Scannell is a Bay Area physician and the author most recently of "Flood Stage."
© Copyright 2012, Kate Scannell
Can physical exercise be unhealthy for you?
Throughout my career as a doctor, this question certainly ranks amongst "the top 10" questions ever raised by my patients. Typically, it was asked by patients who, like Mark Twain, had "never taken any exercise except sleeping and resting" and intended to argue against my recommendation for a healthy dose of physical activity.
Everyone, it seemed, could recount a cautionary tale about a friend or family member who had suffered some ungodly accident or illness in the course of exercising. Fatal heart attacks while jogging. Disastrous collisions with automobiles while biking. Asthma flares while swimming and head injuries from diving. A patient once justified abandonment of her walking routine after being pecked by a giant wild turkey. Comedian Red Skelton famously joked that he got his exercise "on the golf course -- when I see my friends collapse, I run for the paramedics."
Because exercise causes chemical and hormonal changes in the body, I always speculated that it could affect different people differently -- sometimes, in a negative manner. After all, people varied in their biochemical responses to other physiologic stimuli like medications or food. But without any credible evidence regarding exercise, how could you say when and if exercise might be harmful?
Well, I suppose all the exercise naysayers feel somewhat vindicated now. A study published May 30 in the online journal PloS found that about 10 percent of people experienced an adverse health effect from exercising. Researchers drew this conclusion after careful analysis of data accumulated from six exercise studies involving about 1,700 people. Overall, for approximately one in 10 people, exercise worsened at least one risk factor for heart disease -- like blood pressure, triglycerides, fasting insulin levels or HDL cholesterol. And, at the heart of the problem, the researchers didn't understand why these differences occurred or which people were more likely to suffer them.
In truth, I'm worried that patients whose only exercise has been pushing their luck will run with this study. I'm concerned that some will jump to the wrong conclusion and misread it as justification for a sedentary lifestyle.
The emergence of the study also likely reinforces the common belief that if you just wait long enough, medical research will ultimately generate a new truth that finally aligns with your lifestyle choices. Many of us patiently await the scientific proof for chocolate curing diabetes. Potato chips preventing cancer. Butter making us smarter. Cupcakes resolving psoriasis.
While the new study reveals information that is not too surprising, it does have the power to startle by virtue of representing the first serious comprehensive effort to examine whether regular exercise might be harmful.
We doctors have been promoting exercise since time immemorial -- yes, throughout many centuries, and before the elliptical bike or Spandex even existed. What took so long for medical research to raise such an obvious question?
We likely would have known more about health consequences of exercise if there existed greater profit-generating opportunities to capitalize on such research. But there's no money to be made in a physician's recommendation that a patient walk 30 minutes each day, while millions of dollars are thrown at research in quest of a new pill to lower cholesterol or reduce weight.
This point is further underscored by a second study published this month that purports to be the first thorough and detailed review of the medical literature concerning cardiac problems associated with excessive endurance training and exercise.
The publication in this month's issue of the Mayo Clinic Proceedings analyzes more than 50 studies following athletes participating in extreme endurance events like long-distance bicycle racing and ultra-marathons. It reveals a significantly higher -- but still, relatively low -- incidence of cardiovascular damage like heart enlargement and scarring, as well as irregular heart rhythms.The study's lead author emphasized that while extreme exercise can be unhealthy, 30 to 60 minutes per day remains healthy and helpful for most people.
From these two new studies we can conclude that the vast majority of people who engage in regular exercise enjoy health benefits without harm, and that serious cardiovascular damage due to extreme endurance exercise remains an exceptional risk. Both studies also remind us that we have been running on unexamined assumptions about exercise and physical activity for too long a time.
Even knowing from the first study that at least one cardiovascular risk factor worsened with exercise for about 10 percent of people still doesn't tell us whether those people actually suffered more heart attacks or shorter lifespans. That's another assumption that urgently needs to be examined.
Meanwhile, we might rest assured that no medical research yet substantiates any cardiovascular benefit from channel-surfing and couch potato-ing. And exercise -- like most inclinations -- can prove harmful when taken to an extreme. We need to find a healthy middle ground on which to exercise good judgment while also learning to hurdle over unhealthy assumptions that throw us off-track.
===============================
Kate Scannell is a Bay Area physician and the author most recently of "Flood Stage."
© Copyright 2012, Kate Scannell