People
Why We Should Exercise
(No, Not Just to Lose Weight)
AARON E. CARROLL
Last year, I wrote a column arguing that evidence shows that diet,
not exercise, is the key to weight loss. Since then, I have been
troubled at how some readers have taken this to mean that exercise
therefore has no value.
Nothing could be further from the truth. Of all the things we as
physicians can recommend for health, few provide as much benefit as
physical activity.
In 2015, the Academy of Medical Royal Colleges put out a report calling exercise a “miracle cure.”
This isn’t one of those things with just some cohort or case-control
studies behind it, either. There are many, many randomized controlled
trials. A huge meta-analysis examined the effect of exercise therapy on
outcomes in people with chronic diseases.
Let’s start with musculoskeletal diseases.
Researchers found 32 trials looking specifically at the effect of
exercise on pain and function of patients with osteoarthritis of the
knee alone. That’s incredibly specific, and it’s impressive so much
research has focused on this one topic. Exercise improved those
outcomes.
Ten more studies showed, over all, that exercise therapy increases
aerobic capacity and muscle strength in patients with rheumatoid
arthritis. Other studies proved its benefits in other musculoskeletal
conditions, like ankylosing spondylitis, and even some types of back
pain.
For people (mostly middle-aged men) who had had a heart attack, exercise
therapy reduced all causes of mortality by 27 percent and cardiac
mortality by 31 percent. Fourteen additional controlled trials showed
physiological benefits in those with heart failure. Exercise also has
been shown to lower blood pressure in patients with hypertension, and
improve cholesterol and triglyceride levels.
People with diabetes who exercise have lower Hba1c values, which is the
marker of blood sugar control, low enough to probably reduce the risk of
complications from the disease. Twenty randomized controlled trials
have showed that patients with chronic obstructive pulmonary disease can
walk farther and function better if they exercise.
Multiple studies have found that exercise improves physical function and
health-related quality of life in people who have Parkinson’s disease.
Six more studies showed that exercise improves muscle power and
mobility-related activities in people with multiple sclerosis. It even
appeared to improve those patients’ moods.
The overall results of 23 randomized controlled trials showed that
exercise most likely improves the symptoms of depression. Five others
appear to show that it improves symptoms in patients with chronic
fatigue syndrome. In trials, exercise even lessened fatigue in patients
who are undergoing therapy for cancer.
What other intervention can claim results like these?
Even studies of older, hospitalized patients show a beneficial effect
from multidisciplinary interventions that include exercise. Those
randomized to such interventions in the hospital were more likely to be
discharged to go home, and to spend less time in the hospital over all -
and at a lower cost.
While we don’t think of it this way, you can make a pretty good argument
that exercise is as good as drugs for many conditions. A 2013
meta-analysis of meta-analyses (that’s how much data we have) combined
and analyzed the results from 16 reviews of randomized controlled trials
of drug and exercise interventions in reducing mortality. Collectively,
these included 305 trials with almost 340,000 participants.
Diuretic drugs (but not all drugs) were shown to be superior to exercise
in preventing death from heart failure. But exercise was found to be
equally good as drugs in preventing mortality from coronary heart
disease. Exercise was better than drugs in preventing death among
patients from strokes.
Many people will be surprised at how little you need to do to achieve
these results. Years ago, in an effort to get in shape, I tried the P90X
routine. It proved too hard for me. Later, when I tried ‘Insanity’
workout, it beat me so badly that people at work kept asking me if I was
ill. Two years ago, I tried P90X3. It was a bit more manageable, but I
still couldn’t keep it up.
I’m not alone in thinking that physical activity to improve health
should be hard. When I hear friends talk about exercising, they discuss
running marathons, participating in cross-fit classes or sacrificing
themselves on the altar of Soul Cycle. That misses the point,
unfortunately. All of these are way, way more than you need to do to get
the benefits I’ve already described.
The recommendations for exercise are 150 minutes per week of moderate
intensity physical activity for adults, or about 30 minutes each
weekday.
Moderate intensity is probably much less than you think. Walking
briskly, at 3 to 4 miles per hour or so, qualifies. So does bicycling
slower than 10 miles an hour. Anything that gets your heart rate
somewhere between 110 and 140 beats per minute is enough. Even
vacuuming, mowing the lawn or actively walking your dog might qualify.
Today, my goals are much more modest. Trekking from my office to the
clinic and back again gives me 30 minutes of exercise. Or, I walk to the
supermarket from my office to grab lunch, at a mile each way. In colder
weather, I spend half an hour on the elliptical machine. Doing this
five days a week gets me the activity I need.
While it feels as if there’s nothing we can do to change people’s
behavior, evidence exists to the contrary. A systematic review and
meta-analysis of advice and counseling by health professionals found
that promotion of physical activity works. Doctors and clinics that made
efforts to promote exercise to patients needed to engage 12 adults on
the subject in order to get one additional adult to meet recommended
levels of activity one year later. That might not sound impressive, but
it’s one of the best measures of “number needed to treat” that I’ve
presented.
If that’s the best “counterpoint,” then physical activity seems like a no-brainer.
[The author is a Professor of Pediatrics at Indiana University School of Medicine.]
[Courtesy: The New York Times. Edited for sikhchic.com]
June 22, 2016