April 3, 2014
News Review From Harvard Medical School -- Early Fitness May Help Keep Brain Agile
Physically fit young adults may have more nimble brains later on, a new study suggests. The study included 2,700 men and women. They were 18 to 30 years old when the study began. They were given treadmill tests that involved walking or running as the speed and incline of the treadmill increased. On average, people lasted about 10 minutes before they had to stop. Then they took the same test 20 years later. On average, time on the treadmill decreased by just under 3 minutes. About 25 years after the first treadmill test, people were given tests of memory and mental reaction time. People who performed better on the first treadmill tests also did better on these memory and thinking tests. There were also "trick questions." An example might be asking the color of the word "yellow," which was written in green (correct answer: "green"). People who had the smallest decline in their treadmill times over 20 years also did better on these trick questions. The differences were small. But researchers said they were larger than the average effect of a year of aging. The journal Neurology published the study. Reuters news service wrote about it April 2.
By Robert H. Shmerling, M.D.
Harvard Medical School
What Is the Doctor's Reaction?
Here's something you've probably heard before: exercise is good for you.
But it may be even better for you than previously thought. A new study reveals how physical fitness in early adulthood may help to preserve mental fitness.
The medical journal Neurology published the study. Researchers enrolled more than 2,700 young adults (average age 25). They were all given treadmill tests, similar to a stress test. They were asked to walk or run as long as they could while the speed and incline of the treadmill were gradually increased. The treadmill test was repeated 20 years later. Each person had tests of thinking skills 25 years after the first treadmill test.
The findings suggest that physical fitness during early adulthood could have a profound effect on brain function decades later. For example:
- Performance on the treadmill test did decline during the 20 years between tests. But those who declined the least had the best scores on tests of thinking skills. These included tests of memory, planning and speed of transforming thoughts into action (psychomotor speed).
- Those who were most physically fit as young adults had the best verbal memory and psychomotor speed scores 25 years later.
- The link between exercise capacity during young adulthood and future brain function held up even after accounting for factors that increase the risk of heart and blood vessel disease. These risk factors include diabetes, smoking and high cholesterol.
- What makes this study particularly important is that the measures of brain function it assessed are among the best predictors of future dementia. It's still unproven, but this study raises the real possibility that physical fitness from early adulthood through middle age might help prevent dementia in later years. Ways to prevent dementia are essential because we don't know the causes or have good treatments for the most common types of dementia.
What Changes Can I Make Now?
Review your current exercise capacity. For example:
- Can you climb 2 or 3 flights of stairs without difficulty?
- Can you easily walk, jog or bike for 10 minutes or more?
- Has your stamina or speed diminished in recent years?
Now review how physically active you are. For example:
- Do your hobbies, work or home life require you to be physically active?
- Do you walk (or sit) for much of the day?
- Do you exercise most days of the week?
There may be good reasons that you aren't as active as you would like. Medical conditions, such as lung or heart disease, may limit your exercise capacity. Some medicines can affect your stamina. And clearly there are challenges to getting regular exercise if your circumstances (for example, working two jobs or caring for kids) leave you little free time.
Even so, there may be changes you can make to increase your physical activity and improve your exercise capacity. Here's what you can do:
- Take the first step. Commit to becoming more physically active.
- Make physical activity a routine part of your day. Small changes, such as taking the stairs instead of the elevator, can add up.
- Choose an activity you like. If you are inactive now, walking, swimming or riding a stationary bike are good places to start. Set realistic goals, and don't try to do too much too soon.
- Vary the activities. "Cross-training" will reduce the chance that boredom or injury will get in the way of regular exercise.
- Get an exercise partner. You can encourage each other to exercise when you might be tempted to skip it. Exercise that includes a social aspect also tends to be more fun.
If you have any major medical conditions or aren't sure how much exercise you can safely handle, review your options with your doctor.
What Can I Expect Looking to the Future?
If physical fitness can stave off dementia, researchers will try to figure out why. Understanding the connections between physical activity and brain function could lead to new insights into the causes of dementia. And that could lead to new preventive strategies and treatments.
Experts predict that dementia will become dramatically more widespread in the years to come. I hope that we also will see physical activity become more of a priority for everyone. This will be especially important if physical fitness can prevent dementia, as this latest research suggests.