How exercise in young adulthood affects hypertension: a UCSF study

Keeping your heart healthy through exercise is not something you can simply front-load early in life. Evidence indicates that if you want to reduce the chance of developing high blood pressure in later years, you need to sustain strong activity levels right through middle age.

A large study spanning more than 5,000 people in four US cities also indicates that social circumstances can make it harder for some groups to keep moving than for others.

"Teenagers and those in their early 20s may be physically active but these patterns change with age," epidemiologist Kirsten Bibbins-Domingo from the University of California, San Francisco (UCSF) explained in April 2021, when the research was published.

Why physical activity in young adulthood matters for hypertension

Many past studies have linked exercise with lower blood pressure. This 2021 work adds that "maintaining physical activity during young adulthood – at higher levels than previously recommended – may be particularly important," Bibbins-Domingo said.

Hypertension (high blood pressure) is a major health problem affecting billions of people across the globe. It raises the risk of heart attacks and stroke, and it is also associated with a greater likelihood of developing dementia later in life.

The World Health Organization estimates that more than one in four men and roughly one in five women have hypertension. Even so, many people living with high blood pressure are unaware of it, which is why it is often referred to as the "silent killer".

There are, however, practical ways to improve high blood pressure, and exercise is the central focus of this research.

How the UCSF study measured exercise and blood pressure over decades

The researchers enrolled more than 5,100 adults and followed them for three decades, combining physical examinations with questionnaires covering exercise patterns, smoking status, and alcohol consumption.

At every clinic visit, blood pressure readings were taken three times, with 1 minute between measurements. For the analysis, participants were then classified into four groups based on race and gender.

In all groups-men and women, and across both racial categories-physical activity dropped sharply between the ages of 18 and 40. In the decades that followed, hypertension became more common as activity levels continued to decline.

The authors argue that this points to young adulthood as a key period for prevention, where health promotion programmes aimed at increasing exercise could help reduce hypertension in midlife.

"Nearly half of our participants in young adulthood had suboptimal levels of physical activity, which was significantly associated with the onset of hypertension, indicating that we need to raise the minimum standard for physical activity," said lead author Jason Nagata, a UCSF expert in young adult medicine.

When the team focused on people who completed 5 hours of moderate exercise per week in early adulthood-twice the minimum amount currently advised for adults-they found a markedly lower risk of hypertension. The benefit was greatest for those who kept up those exercise habits through to age 60.

"Achieving at least twice the current minimum adult [physical activity] guidelines may be more beneficial for the prevention of hypertension than simply meeting the minimum guidelines," the researchers write in their paper.

Even so, increasing weekly exercise is not straightforward when people are navigating major life choices and taking on expanding responsibilities.

"This might be especially the case after high school when opportunities for physical activity diminish as young adults transition to college, the workforce, and parenthood, and leisure time is eroded," said Nagata.

Racial disparities and the social factors shaping activity levels

The study also highlighted a stark difference in health pathways for Black participants compared with White participants. By age 40, physical activity levels levelled off among White men and women, while activity among Black participants continued to fall.

At age 45, Black women overtook White men in hypertension rates. Meanwhile, White women recorded the lowest levels of hypertension across midlife.

By age 60, hypertension affected roughly 80 to 90 percent of Black men and Black women. By comparison, the figure was just under 70 percent for White men and about half for White women.

The researchers connected these established racial gaps to a range of social and economic influences. However, those drivers were not directly measured in this study, although educational attainment at high school level was noted.

"Although Black male youth may have high engagement in sports, socioeconomic factors, neighborhood environments, and work or family responsibilities may prevent continued engagement in physical activity through adulthood," Nagata said.

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

An earlier version of this article was published in April 2021.