Researchers found that adults who were physically fit at the ages of 45-50 were much less likely to experience stroke in later life.
Stroke is one of the leading causes of long-term disability and death in the United States.
According to the Centers for Disease Control and Prevention (CDC), each year, more than 795,000 Americans have a stroke, and around 130,000 die as a result.
The 2008 Physical Activity Guidelines for Americans recommend that adults aged 18-64 get around 150 minutes of moderate-intensity aerobic activity or 75 minutes of vigorous-intensity aerobic activity each week.
However, results from the 2014 National Health Interview Survey showed less than half of adults in the U.S. meet these guidelines.
First author Dr. Ambarish Pandey, of the Southwestern Medical Center at the University of Texas, and colleagues hope their latest findings - published in the journal Stroke - will encourage adults to increase their exercise levels.
"We all hear that exercise is good for you, but many people still don't do it," says Dr. Pandy. "Our hope is that this objective data on preventing a fatal disease, such as stroke, will help motivate people to get moving and get fit."
High fitness reduced stroke risk by 37 percent
For their study, the team analyzed 19,815 adults who were part of the 1970-2009 Cooper Center Longitudinal Study.
When the study participants were aged 45-50, they took part in a standardized treadmill test that measured their cardiorespiratory fitness.
Cardiorespiratory fitness is a measure of how well the heart and lung can supply the muscles with oxygen during prolonged physical activity, and how well the muscles use this oxygen. The higher a person's cardiorespiratory fitness, the more physically fit they are deemed to be.
Based on the results of the treadmill test, the researchers allocated the participants to one of three groups: low, middle, or high cardiorespiratory fitness.
Compared with participants who had the lowest cardiorespiratory fitness aged 45-50, those who had the highest cardiorespiratory fitness were found to be at 37 percent lower risk of stroke after the age of 65.
The researchers say their findings highlight the importance of good physical fitness at all stages of life.
"Low fitness is generally ignored as an actual risk factor in clinical practice. Our research suggests that low fitness in midlife is an additional risk to target and help prevent stroke later in life."
Dr. Ambarish Pandey
"These findings support the unique and independent role of exercise in the prevention of stroke," adds senior study author Dr. Jarett Berry, an associate professor of internal medicine at Southwestern.