New U.S. research has found that maintaining a healthy weight is one of the most important factors for keeping blood pressure low as we grow older.

Presented on Friday at the American Heart Association (AHA) Council on Hypertension, AHA Council on Kidney in Cardiovascular Disease, American Society of Hypertension Joint Scientific Sessions 2017 in San Francisco, the study looked at the impact of five health behaviors on blood pressure levels over a 25-year period.

These behaviors included a healthy body weight (measured as a body mass index less than 25 kg/m2), never smoking, zero to seven alcoholic drinks weekly for women and zero to 14 for men, 150 minutes or more moderate to vigorous physical activity per week, and eating a healthy diet based on adhering to the Dietary Approaches to Stop Hypertension eating plan.

A total of 4,630 participants from the Coronary Artery Risk Development in Young Adults Study were recruited for the research, with all subjects between 18 to 30 years old in 1985 and 1986 when the study started.

During the following 25 years the researchers measured blood pressure and health behaviors eight times.

The analysis showed that maintaining a healthy body weight appeared to be more important for maintaining a normal blood pressure than the other four behaviors, with participants who kept their weight in check 41 percent less likely to have increasing blood pressure as they grew older.

Never smoking and no or moderate alcohol consumption were also associated with a lower increase in blood pressure by middle age, but the team added that a larger study is needed to confirm these results.

Perhaps surprisingly, no association was found between physical activity or a healthy diet and any changes in blood pressure during the 25-year period.

When looking at the behaviors combined, the team also found that those who maintained at least four of the health behaviors were 27 percent more likely to have a normal blood pressure than an increasing blood pressure as they aged.

"Increasing blood pressure at younger ages is associated with earlier onset of heart disease and stroke, and US high blood pressure treatment guidelines support maintaining healthy behaviors across the lifespan to limit rises in blood pressure as we age," said John N. Booth III, Ph.D., "This data suggests that body weight is very important in terms of maintaining a normal blood pressure from early and into middle adulthood. The other behaviors we studied may play an important role since they can influence body weight."

Booth also stressed that although the other four behaviors included in the study were not as closely linked to maintaining blood pressure as a healthy weight was, they still have clear benefits for health in general.