Physical activity tied to greater odds of objective, subjective hot flashes

Key takeaways:

• Acute increases in physical activity were tied to greater odds of objective and subjective waking and sleeping hot flashes.
• Temperature increases were tied to greater odds of subjective sleeping hot flashes.

Acute increases in physical activity were associated with greater odds of objective and subjective hot flashes during waking and sleeping periods, according to findings published in Menopause.

“Due to the changes in body temperature at night and different aspects of temperature regulation that may be in effect during the day vs. night, the relationship between temperature and hot flashes may be different between sleep and wake periods,” Sarah Witkowski, PhD, associate professor of exercise and sport studies at Smith College, and colleagues wrote. “Measures of external temperature and humidity can help us better understand the relationships between hot flashes and physical activity as the hot flash response to physical activity may change based on ambient conditions.”

Witkowski and colleagues analyzed data from 188 midlife women aged 45 to 55 years in western Massachusetts who wore ambulatory monitors to continuously measure hot flashes, physical activity, temperature and humidity for 24 hours from October to April from 2019 and 2023. Researchers assessed objective hot flashes by sternal skin conductance and subjective hot flashes by women pressing an event marker and data logging. Researchers measured physical activity and defined sleep and wake periods with wrist-worn accelerometers.

Following acute physical activity increases, researchers observed greater odds of objective (OR = 1.31; 95% CI, 1.17-1.47; P < .001) and subjective (OR = 1.16; 95% CI, 1-1.33; P = .03) waking hot flashes. In addition, acute increases in physical activity were also tied to greater odds of objective (OR = 1.17; 95% CI, 1.03-1.35; P < .01) and subjective (OR = 1.72; 95% CI, 1.52-2.01; P < .001) sleeping hot flashes.

Temperature increases were tied to greater odds of subjective sleeping hot flashes only (OR = 1.38; 95% CI, 1.15-1.62; P < .001) and not objective sleeping hot flashes.

Researchers observed no evidence for a relationship between humidity and odds of experiencing any hot flashes.

“These results can be used to inform patients that acute increases in physical activity during the day may be followed by hot flashes; however, physical activity has numerous benefits to health and women should not be discouraged from physical movement at midlife,” the researchers wrote. “Further, restlessness and increased microclimate temperature at night may precede hot flashes, therefore environmental and behavioral measures ... may provide benefit.”