Physical activity is an important way people can lower their blood pressure, according to the American College of Cardiology/American Heart Association guidelines for hypertension, or high blood pressure, in adults. However, not much is known about how physical activity levels in young adulthood affect hypertension risk through middle age.

Young adults need about twice the two-and-a-half hours per week of moderate intensity exercise recommended by the U.S. Department of Health and Human Services (HHS) if they are to reduce their risk of hypertension in middle age, according to a recent study. And these physical activity levels must be maintained through their 30s, 40s, and 50s to give them the most benefit.

The level of physical activity a person had at 18 was strongly linked to his or her likelihood of developing hypertension. But don’t rest on your laurels.

“Our study suggests that maintaining physical activity levels, at higher levels than previously recommended, may be particularly important,” Kirsten Bibbins-Domingo, senior author on the study and a professor of epidemiology and biostatistics at the University of California, San Francisco, explained.

Data from more than 5,000 men and women between the ages of 18 and 30 and enrolled in the prospective, community-based Coronary Artery Risk Development in Young Adults (CARDIA) study were analyzed for the study by researchers from UCSF’s Benioff Children’s Hospitals. Data were collected at four sites nationwide over a 30-year follow-up period.

The young Black and white men and women who were part of the study were divided into four groups by their race and gender. At each of nine physical examinations that were part of the study, participants filled out a questionnaire about their activity levels.

Vigorous-intensity activities included running, racquet sports, bicycling faster than 10 miles per hour, swimming, vigorous exercise classes, active sports such as basketball or football, heavy lifting, carrying or digging on the job, or chores like shoveling snow and lifting heavy objects. Moderate-intensity activities included nonstrenuous sports like softball, walking, bowling, golf or home maintenance, calisthenics and chores like gardening or raking.

Black men were the most active in young adulthood. Those reporting the highest physical activity levels far exceeded the HHS recommendations. They exercised more than young white men and significantly more than young women of either race. But by the time Black men reached age 60, their exercise levels overall had decreased to the recommended levels.

Black men in middle age also tended to exercise less than white men of the same age and a little more than middle-aged white women. They also reported the highest rates of smoking in midlife, and this may have been a factor in their no longer continuing to exercise over time.

Physical activity also declined as white men moved through their twenties and thirties, before leveling off at around age 40. Among white women, physical activity declined a little in their thirties, then stayed steady until age 60.

Black women had the least physical activity of the four groups regardless of age and fairly consistently did less than the amount recommended by the Department of Health and Human Services.

Black men were the most active in young adulthood. Those reporting the highest physical activity levels far exceeded the HHS recommendations.

With these changing levels of activity in mind, researchers examined the rates of hypertension, defined as a blood pressure reading of 130/80 mm Hg or greater, among participants.

Unsurprisingly, the study found the declining activity seen in middle age was reflected in rising rates of hypertension. About 80 to 90 percent of Black men and women had hypertension by the time they turned 60 years old. The numbers were a little better among white men and women: slightly less than 70 percent of white men and 50 percent of white women had hypertension by age 60.

Life Happens
People tend to be most physically active when they are in still in school, Jason Nagata, first author on the study, told TheDoctor. Schools have physical education requirements and people are participating in team sports.

In adulthood, however, easy access to many of those structured programs falls by the wayside. The demands of work and starting a family also can take up time that might formerly have been spent on exercise. “So educational and life changes can lead to a decline in physical activity levels,” he pointed out.

The level of physical activity a person had at 18 was strongly linked to his or her likelihood of developing hypertension. But don’t rest on your laurels. Having been an active young adult is not likely going to protect you from hypertension if you don’t make an effort to exercise. The results make it clear that the best way to head off high blood pressure is to remain active.

If your activity levels have already gone down, think of small changes you can make to become more physically active — walk places instead of driving; run while pushing your child in a stroller; ride a bike; do yard work. As Nagata, an assistant professor of pediatrics at UCSF, says, “Every journey starts with a single step. There are daily opportunities for people to increase their physical activity level,” you just need to find those that fit your situation and interests best.

The study is published in the American Journal of Preventive Medicine.