Middle-aged and older adults with excess weight or obesity can improve their blood pressure (BP), and therefore their cardiovascular health, simply by walking briskly for a half hour in the morning because the benefit is sustained for several hours, a small study suggests.
Moreover, in women only, following the morning walk with regular interruptions in sitting — that is, 3 minutes of less intense walking breaks every half hour — resulted in an even lower average systolic blood pressure during an 8-hour test period.
The study in 67 sedentary adults 55 to 80 years of age, was published online February 20 in the journal Hypertension.
"Traditionally, the health effects of exercise and sedentary behavior have been studied separately," lead author Michael Wheeler, PhD candidate at the University of Western Australia in Perth, who works at the Baker Heart and Diabetes Institute in Melbourne, said in a statement from the American Heart Association (AHA). "We conducted this study because we wanted to know whether there is a combined effect of these behaviors on blood pressure."
"Combining exercise with regular breaks from sitting may be of more benefit for lowering BP in women than in men," the researchers write.
"Although longer-term studies are required to corroborate our findings," they conclude, "this line of evidence may inform clinical and public health discussions around tailored strategies to optimize BP targets in older adults with increased cardiovascular disease risk."
Invited to comment, AHA spokesperson Gina Price Lundberg, MD, clinical director, Emory Women's Heart Center, and associate professor, Emory University School of Medicine in Atlanta, cautioned that this was a very small study, under very controlled conditions, including standardized meals and treadmill walking at a fixed intensity.
Nevertheless, "I think it is one more study that proves exercise is so important," she told theheart.org | Medscape Cardiology.
"Most heart attacks happen in women after 60 and men after 50," Lundberg noted, "and it's an important group to reduce the risk." Taking a walk every morning and then taking breaks from sitting is "just so simple."
It is not necessary to use a treadmill, she added. "You can exercise in your house, outside of your house, anywhere, just simply walk."
Some patients are looking for a quick fix, a special diet, or a new pill, Lundberg added, but this study reinforces "how important consistent, even small amounts of exercise are for their overall health."
It is not known whether the acute BP lowering caused by exercise is attenuated by prolonged sitting or enhanced by subsequent breaks in sitting, Wheeler and colleagues write.
To investigate this, they examined data from a study designed to examine cognitive performance in middle-aged or older overweight or obese patients.
The study recruited 67 sedentary patients (including 35 women) who had a mean age of 67 and a mean BMI of 31 kg/m².
The patients had a mean systolic BP of 125 mm Hg and a mean diastolic BP of 74 mm Hg, and 37% had hypertension, defined as systolic BP of at least 130 mm Hg or diastolic BP of at least 80 mm Hg, according to the most recent American guidelines.
They completed three 8-hour physical-activity conditions in the testing laboratory, separated by 6 days. The three conditions, starting at 8 AM, were:
- Uninterrupted quiet sitting for 8 hours (sedentary condition)
- 1 hour sitting, then 30 minutes of moderate-intensity treadmill walking, then 6.5 hours of sitting
- 1 hour sitting, then 30 minutes of moderate-intensity treadmill walking, then 6.5 hours of sitting interrupted by 3 minutes of light-intensity treadmill walking every 30 minutes
In each condition, the patients received a standard pretest dinner the night before and breakfast and lunch on the test day.
Overall, when they walked for half an hour in the morning and then sat, their 8-hour average systolic and diastolic blood pressures were lower by 3.4 mm Hg and 0.8 mm Hg, respectively, than in the sedentary condition, and when they also interrupted their sitting with brief walking breaks, their average systolic and diastolic blood pressures were lower by 5.1 mm Hg and 1.1 mm Hg, respectively, than in the sedentary condition (P < .05 for all).
A closer look showed that the added systolic BP lowering benefit of sitting breaks was only seen in women.
The researchers note that with pharmacotherapy, a 10 mm Hg drop in systolic BP and a 5 mm Hg drop in diastolic BP is associated with a 22% lower risk for death from coronary heart disease and a 41% lower risk for death from stroke.
The study also showed that epinephrine increased after exercise in men but decreased after exercise in women. The reasons for this are not known.
A much larger study in 1600 patients in their early 60s, published last August, Lundberg noted, showed that exercise was linked with positive changes in biomarkers C-reactive protein, interleukin 6, and leptin, with greater benefits among women.
The research was funded by a grant from the National Health and Medical Research Council of Australia and partly supported by the Victorian Government's Operational Infrastructure Support Program. The authors have no relevant financial disclosures.
Hypertension. Published online February 20, 2019. Abstract