I Know I Should Exercise, But…
By Wayne N. Leimbach, Jr., MD, FACC, FSCAI, FCCP, FAHA
Everybody knows they should exercise, but most of us feel we don’t have the time, or think we can’t do the exercise activity level needed to get any benefit. To further confuse us, the recommendations in the media vary greatly and often reflect a particular sales pitch for exercise equipment, a workout program or a health club membership.
So what does the scientific data say regarding how much someone should exercise to lead a healthier life?
First, some people question how much benefit someone actually gains from routine exercise. Wouldn’t living longer be a good incentive to exercise?
Dr. Steven Blair at the Cooper Clinic in Dallas, Texas, has evaluated greater than 70,000 individuals with maximal exercise treadmill testing since 1970. Maximum exercise treadmill tests were performed at baseline on all patients, and the majority had follow up exercise treadmill tests over the subsequent years. He divided the subjects into three categories: the “unfit” (lower 20 percent based on time on the treadmill adjusted for gender and age), the “moderately fit” (the next 40 percent of patients based on time on the treadmill), and the “high fitness” group (which included the top 40 percent based on time on the treadmill). He collected the mortality rates during the 18 years of follow up for both men and women based on whether they were initially found to have a low, moderate, or high level of fitness on the initial treadmill testing.
He found a greater than 50 percent reduction in mortality for women by just being in the moderately fit group as compared to the low fit group, and moderately fit men had an even greater reduction as compared to the low fit group.
In addition, people who initially tested as “unfit” on the first exam and remained in the “unfit” category at follow up exams had a two-fold higher mortality rate than those who initially tested as unfit on the first exam, but then tested moderately fit on the follow up exams.
For those subjects who tested fit on both the initial and follow up treadmill tests, there was a 60 percent lower mortality rate as compared to the unfit group, so exercising even to a moderate level of fitness can substantially decrease all cause mortality.
Many people think you have to jog or run a marathon to make a difference. The real question for them is, “How little can I do to make a difference in my health and my life?”
Dr. Timothy Church, Director of the Pennington Biomedical Research Center at Louisiana State University measured the effects of different doses of physical activity on cardiopulmonary fitness among sedentary, overweight, or obese postmenopausal women. Women were randomly assigned to one of four groups. The first group was a non-exercising group, which served as a control. The second group was a low exercise group that walked 72 minutes a week. The third group was a moderate level exercising group that walked 136 minutes per week, and the fourth group was a high level exercise group that walked 192 minutes per week. After six months, the control, non-exercising group experienced a 1.7 percent decrease in physical fitness as compared to a 3.8 percent, 6.7 percent, and 9.1 percent improvement in fitness for the low, moderate, and high exercise level groups respectively.
These findings showed that just a 10 minute walk seven days a week not only prevented the deterioration in fitness that was seen in the non-exercising group, but the 10 minute a day walk produced a measurable increase in fitness in just six months.
So, the smallest amount of exercise time to produce a measurable benefit in health is a 10-minute walk seven days a week.
The United States Government has produced a Physical Activity Guideline similar to what the government has done in regards to nutritional recommendations. The guideline recommends that adults accumulate two hours and 30 minutes a week of moderate intensity exercising, which includes walking. So, 30 minutes of walking five days a week produces a significant improvement in health.
There have been several studies, which show that a person doesn’t have to be a marathon runner to gain benefits from exercise. Studies have shown that simple strategies to increase one’s daily activity produce long term benefits. Such strategies include walking more than 10,000 steps a day or simply doubling the number of steps a person walks each day. People who consistently use the stairway in their workplace instead of the elevator also showed benefit over time.
Most everyone knows they should exercise, but most don’t realize that even a 10-minute walk once a day produces a substantial benefit. So, there is no need to buy any special exercise equipment or join a health club unless you want to do more.
It is important to remember that it is far better and easier to maintain good health than try to regain it once it is lost.