December 20, 2013
News Review From Harvard Medical School -- More Walking Protects Heart for Pre-Diabetics
Walking more can decrease the risk of heart attack, stroke and death among high-risk adults, a study finds. The study included 9,300 people with pre-diabetes. People with this condition have above-normal blood sugar. It's not high enough to diagnose diabetes. But they have higher risks of type 2 diabetes, heart attack and stroke. Everyone in the study was in a program to help them exercise more, lose weight and improve their diets. At the start of the study, people were wore pedometers for a week to record how many steps they took daily. They did this again a year later. People who walked more when the study began were healthier during the 6-year follow-up period. For every 2,000 steps people took daily, they were 10% less likely to have a heart attack or stroke or die. These numbers were adjusted to account for other factors that affected people's risk. Increasing walking during the first year reduced risk even more. For every increase of 2,000 steps daily, people's risk of heart attack, stroke and death dropped 8%. The journal Lancet published the study. HealthDay News wrote about it December 20.
By Mary Pickett, M.D.
Harvard Medical School
What Is the Doctor's Reaction?
Want the perfect stocking stuffer? Are you looking for a low-cost item that can provide your loved one -- or you -- with health and a longer life expectancy? Consider a pedometer.
A new study looked at pedometer use among more than 9,000 adults from 40 countries. Researchers checked to see if higher step counts offered protection against heart attack and stroke.
After six years of study, the results were released this week. They were impressive.
First the researchers looked at the number of steps that people made part of their daily routine before the study. Remarkably, for this group of adults, every 2,000 steps in baseline daily routine predicted a 10% lower risk of heart attack and stroke during the years of the study.
People also were encouraged to increase their daily activity. Step counts were rechecked 12 months into the study. Every 2,000 steps that were added to a daily routine by the end of the first year matched up with an 8% decrease in heart attack and stroke during later years of the study.
For example, people who started with 5,000 steps per day and increased to 9,000 steps during the first year had a 16% lower risk than they had when the study began. And don't forget that they had started out with an advantage over sedentary adults. (People who are "sedentary" usually walk fewer than 3,000 steps per day.)
The people who were watched in this study were chosen because they had something in common that put them at higher risk for heart disease -- they all had pre-diabetes. This is a mild shift in metabolism that causes blood sugar to be slightly higher than normal. However, it does not cause symptoms of diabetes. And blood sugar is not high enough for a diabetes diagnosis.
Pre-diabetes can lead to diabetes, particularly if a person with this condition does not carefully manage his or her weight.
What I love about this study is that it so reliably measures exercise. Many studies rely on people's reports about how much they exercise. These reports are not always accurate. As a result, some exercise studies end up with watered-down results. But when you count steps with a pedometer, you can quickly see that the benefits of exercise are real.
What Changes Can I Make Now?
Pedometers (step counters) are available in clip-on or bracelet models. One popular version for shoppers this holiday season is the electronic "Fitbit" wrist pedometer.
A step goal can be a perfect New Year's resolution.
For pedometers,10,000 steps per day is a great (laudable, admirable) goal, equal to about 5 miles per day.
I recommend that you first get a sense of your average step count. Then try increasing gradually. Try adding 500 steps a day in your first week. Then you can continue to add another 500 steps a day in each week that follows.
A 2007 review of studies in which people set a goal for step counts found that they increased their physical activity by an average of 27%. They also lost weight and improved their blood pressure. Somehow, many of us respond to the "challenge" of a step count in a way that we can't respond (for long, at least) to a more structured exercise plan.
What Can I Expect Looking to the Future?
The U.S. Centers for Disease Control and Prevention (CDC) is watching rates of obesity. The CDC report and documentary The Weight of the Nation, includes a prediction that obesity rates will increase 42% by 2030. This does not bode well for the risk of heart disease and stroke.
The U.S. surgeon general recommends that adults do moderate aerobic exercise, such as walking, for at least 150 minutes per week. About 75 minutes a week is recommended if the exercise is more intense, such as jogging. Doctors are comfortable with this advice. But fewer than half of U.S. adults are active enough to satisfy this guideline.
Last year, the CDC published a report that found more Americans seem to have started walking.
In 2005, 56% of U.S. adults said they had "walked for transportation or leisure in at least 1 bout of 10 minutes or more in the preceding 7 days." In 2010, 62% of Americans answered "yes" to the same question, the report found.
I am thankful that Americans are at least moving in the right direction.