ORLANDO, Fla. — A few minutes of light activity for people who sit most of the day may lower blood pressure in patients with type 2 diabetes, according to a new study.
Sitting for long stretches of time is known to raise risks for heart attacks, stroke, and diabetes. This current study suggests even light activity breaks may be an easy, practical way to cut down on the health risks related to long periods of sitting among patients with type 2 diabetes, researchers reported at the American Heart Association Scientific Sessions.
“Adults in industrialized countries like the United States and Australia are ‘sitters’ at home, at work, and in the car. Most do not exercise, nor do they participate in sports. Time spent sitting, particularly at work, has increased greatly over the last 50 years. A significantly higher proportion of jobs are now desk-bound and screen-bound jobs. Prolonged sitting is associated with poor control of blood glucose and insulin. Breaking up prolonged periods of sitting can have beneficial effects on important health-related aspects of our metabolism,” said co-author Bronwyn Kingwell, PhD, who is the head of metabolic and vascular physiology at the Baker IDI Heart and Diabetes in Melbourne, Australia.
Dr Kingwell, who presented the data at the meeting, and colleagues tracked blood pressure levels in 24 overweight and obese adults with type 2 diabetes as they sat for 8 hours. Participants either took 3-minute walking breaks averaging a speed of about 2 miles per hour or did 3 minutes of simple resistance exercises every half hour.
Compared with uninterrupted sitting, the researchers found that light walking was linked to an average 10-point drop in systolic blood pressure, and simple resistance activities were associated with an average 12-point drop in systolic blood pressure.
“This is the first study to test this question in individuals with type 2 diabetes, who are at increased risk of cardiovascular disease. It is also the first to explore whether incorporating simple body weight resistance activity bouts as well as light-walking bouts are beneficial for blood pressure,” Dr Kingwell told Endocrinology Advisor.
The study also demonstrated marked blood pressure reductions over trial days when people did the equivalent of walking to the water cooler or some simple body weight movements on the spot.
Previous research has shown that sitting for long periods of time has detrimental effects on metabolic health and that short bouts of physical activity can lower blood pressure in overweight patients without diabetes. Dr Kingwell noted, however, that this is the first study to examine the effects of short, intermittent bouts of light physical activity in patients with type 2 diabetes in a controlled laboratory setting.
In this randomized crossover trial, patients’ mean age was 62 years and mean BMI was 33. About two-thirds of the participants were on antihypertensive medications during the study.
For 8 hours daily on 3 separate days, the individuals ate breakfast and lunch based on their calculated energy requirements. Researchers checked blood pressure and blood norepinephrine levels at regular intervals throughout the day. For light intensity walking, the volunteers took a slow, easy stroll on a treadmill. For simple resistance activities, they did half-squats, calf raises, knee raises, or gluteal muscle squeezes.
“When men and women with type 2 diabetes remained seated for 7 hours, eating breakfast and lunch and only rising for toilet breaks, there was a slow and steady increase in their resting blood pressure across the day. The mean reductions in blood pressure for the activity bouts (mean systolic blood pressure reduction, 14-16 mm Hg; mean diastolic blood pressure reduction, 8-10 mmHg) over the day were clinically meaningful reductions, particularly given many of the patients in this study were already taking medications to lower their blood pressure,” explained Dr Kingwell.
“The reductions in norepinephrine concentrations paralleled these decreases in blood pressure, providing further insights into potential candidate mechanisms such as reduced vasoconstrictor tone, which may be contributing to the hypotensive effect. However, it is likely that there are additional mechanisms at play,” she added.
Dr Kingwell noted that muscles activated when moving increase blood sugar uptake, which is especially important among people with type 2 diabetes. For most people, the American Heart Association recommends at least 150 minutes of moderate exercise each week, such as walking around 3 miles per hour or at least 75 minutes of vigorous exercise each week, such as running at around 5 miles per hour, or a combination of both.
“This is a big public health problem. Humans are designed to move. Our biological systems function optimally when we are regularly physically active. The prolonged periods of sitting that now characterize much of our lives these days, especially our working lives, are missed opportunities for healthy movement. There may be untapped preventive health and clinical management potential through shifting the high volume of time spent sedentary to light-intensity physical activity interspersed throughout the day,” said Dr Kingwell.
- Dempsey PC, Sacre JW, Straznicky NE, et al. Abstract 712 – Interrupting Prolonged Sitting Reduces Resting Blood Pressure and Plasma Norepinephrine in Adults with Type 2 Diabetes. Presented at the American Heart Association Scientific Sessions; November 7-11, 2015; Orlando, FL.