More is usually better when it comes to exercise and physical activity. But even a few hours every week can have an impact on your weight, mood and, as new research shows, blood pressure.
A new review by the American Heart Association found that doing more than four hours of physical activity during leisure time could lower the chance of developing hypertension by almost 20 percent. Moderate activity also reduces the risk by more than 10 percent.
The more recreational physical activities people engage in, the greater protection they have from developing high blood pressure, according to researchers of this review.
"Try to get four hours of activity in per week."
Pengcheng Huai, from the Department of Epidemiology and Health Statistics at Shandong University, led a team of researchers in reviewing 13 previously published studies on how physical activity affected the chance of developing hypertension, which is a risk factor for heart disease.
The studies were published through November 2012 and involved about 136,800 people from the US, Europe and East Asia who did not initially have hypertension. Over the course of the included studies, 15,607 participants developed hypertension.
The researchers of the current study tracked participants' level of physical activity in each of the included studies. Activity level was categorized as high, moderate or low based on what was reported in each individual study.
The included studies were required to look at hypertension as affected by participants' level of recreational activity or occupational physical activity done on the job, such as forestry, farm or industrial work.
Recreational activity encompassed running, jogging, swimming, cycling and other forms of exercise that were done voluntarily and purposefully during the participants' free time.
Physical activity done while commuting, such as walking or cycling to work, was also considered.
Compared to doing low levels of physical activity, the researchers found that doing high levels of physical activity, or exercising more than four hours a week during leisure time, decreased the risk of developing hypertension by 19 percent on average.
Doing moderate physical activity, or one to three hours of exercise a week, also decreased the chances of developing hypertension by 11 percent compared to doing low levels of physical activity.
With physical activity done at work, the researchers found that the links between activity done at work was not significantly tied to decreased hypertension risk.
“To try to lower your risk of high blood pressure, you should exercise more in your leisure time," said Wei Ma, MD, PhD, co-author of the study and associate professor in the School of Public Health at Shandong University, in a press release.
The researchers noted that how physical activity was measured varied from study to study, so definitions of what high, moderate and low levels of activity were not necessarily consistent.
In addition, studies that were not written in English and Chinese were excluded from the review. The researchers also could not take patient characteristics that typically affect hypertension risk into account.
"The results of this meta-analysis further support the common contention that exercise like swimming, jogging or other exercises that you do by choice can have positive benefits on your health. In this case, the benefit is on blood pressure levels where moderate or high levels of physical activity can lead to lower blood pressure. This is important because even if you work at a job that requires physical activity, it doesn't mean that you shouldn't try to work in some outside exercise for the health benefits," Massimiliano Vitale, MD, a physician at Cornerstone Internal Medicine, a department of St. John Hospital and Medical Center, told dailyRx News. "If you are unsure about how to get started, talk to your health care provider about exercise regimens and the best one for you."
The study, supported by the Independent Innovation Foundation of Shandong University, the Research Fund for the Doctoral Program of Higher Education of China and the Foundation for Outstanding Young Scientist in Shandong Province, was published online September 30 in the journal Hypertension.
No conflicts of interest were reported.
