The discomfort of hot flashes can be eased through exercise.
Hot flashes are the most common symptom of a woman's menopause. They are characterized by feelings of intense heat, reddening of the skin caused by increased blood flow, sweating and reduced brain blood flow.
A hot flash lasting 2-3 minutes can increase cutaneous vasodilation, or surface blood flow, by around 80%; and sweating can be five times more than usual. This is comparable to changes brought about by 30 minutes of moderate-intensity cycling, which tends to raise core body temperature by around 0.4-0.6° Celsius.
This puts hot flashes in the category of moderate-to-severe thermoregulatory events.
What causes them is not entirely understood, but they have been linked to raised blood lipids and insulin resistance, which are also potential risk factors for cardiovascular diseases.
A 16-week exercise program
To measure the characteristics of hot flashes and the impact of exercise, researchers, led by Dr. Helen Jones from the Research Institute for Sport and Exercise Sciences at Liverpool John Moores University, recruited 21 healthy symptomatic post-menopausal women.
One group of 14 women undertook a gym-based exercise program for 16 weeks, while the others made no changes to their daily routine.
Participants completed a self-assessment questionnaire about the frequency and intensity of their hot flashes.
Researchers also assessed the women's hot flashes by placing the women in a hot water suit to induce a hot flash and recording their physiological reactions. These included sweating and skin and brain blood flow, which match the descriptions of sweating, flushing and faintness on the self-report questionnaire about hot flashes.
The exercise group worked out in the gym on a treadmill, bike, rower and cross trainer. They increased their breathing and blood flow and they sweated, but they were still able to talk.
They progressed from three 30-minute sessions a week to five 45-minute sessions a week.
Significant reduction in symptoms
After 4 months, the team measured the number and severity of hot flashes again using the same measurements.
In the exercise group, when hot flashes occurred, the amount of sweating was significantly reduced. Blood flow to the skin decreased by 9% at the chest and 7% on the forearms. Blood flow in the brain was minimized. The hot flashes increased heart rate, skin blood flow and sweating, but reduced mean arterial pressure and blood flow in the brain.
In contrast, the women who remained sedentary reported very little difference in hot flash severity.
One limitation of the study was that participants only rated weekly self-reported severity and did not also rate severity during the acute hot flashes assessed in the laboratory. Nevertheless, a reduction in weekly severity was reported, which supports the data collected in the laboratory and the theory that exercise training reduces the severity of post-menopausal hot flashes.
Dr. Jones comments:
"Previous studies have only investigated if post-menopausal women could improve the number and severity of hot flashes using a questionnaire that described symptoms. We have provided direct evidence that the physiological reactions during a hot flash can be improved with regular exercise that makes you fitter."
The findings, say the team, can now be used to promote exercise as a treatment in the management of menopausal hot flashes.
Future research plans include investigating the impact of exercise training on hot flashes related to breast cancer, which can be even more severe.
Medical News Today recently reported that fluctuations in estrogen may lead to depression in women undergoing menopause.