A recent, small study suggested that perimenopausal women experience a greater burden of nocturnal hot flashes during the second half of the night, potentially contributing to a higher risk of cardiovascular disease.

The study involved 60 healthy perimenopausal women aged 43 to 54 years who were free of heart disease and not taking hormone therapy or medications that influence hot flashes. The analysis focused on comparing hot flash frequency between the first and second halves of the night. Findings were presented at the 2024 Annual Meeting of The Menopause Society in Chicago.

Researchers found that 59% of objectively measured hot flashes occurred in the second half of the night, coinciding with periods of rapid eye movement (REM) sleep; 41% of total hot flashes occurred during the first half of the night. Hot flashes were objectively measured via sternal skin conductance. 

The researchers hypothesized that more frequent hot flashes during the second half of the night may be associated with cardiovascular risk due to REM sleep disruptions, but they emphasized that further research is necessary to fully understand this connection.

"This is preliminary data and on a small sample. More research is needed to evaluate the association of hot flashes with sleep disruptions and how they may impact subclinical cardiovascular risk around the transition to menopause," study lead Sarah Witkowski, PhD, said.

The timing of the study is significant, as perimenopause is a period when the risk for cardiovascular disease increases, potentially due to fluctuating hormone levels; particularly, the decline in estrogen. Estrogen helps keep blood vessels open, controls cholesterol levels, and reduces plaque buildup in arteries. As estrogen levels drop, the inner lining of blood vessels may become more vulnerable, raising the risk of heart disease.

"The results of this small study are interesting, as hot flashes are one of the most common symptoms of menopause. Further research into the potential association between sleep disruption and an increased risk of developing cardiovascular disease will be important to women and their healthcare professionals," noted Stephanie Faubion, MD, medical director for The Menopause Society.

The results were presented under the title "Potential Implications for Cardiovascular Disease in Perimenopausal People: Investigating Differences in Nocturnal Hot Flashes in the First vs. Second Half of the Night."

Conflict of interest disclosures were not made available at the time of publishing.