Sustained sleep curtailment disrupts nocturnal vascular responsiveness to spontaneous arousals, more evident in females than in males, providing mechanistic insight into the sex-specific relationship between shortened sleep duration and cardiovascular disease risk in females.
Sleep restriction did not alter heart rate or pulse transit time reactivity in males or females during the early experimental phase.
The heart rate response to spontaneous arousal was altered in a sex-dependent manner following sustained sleep restriction during the late experimental phase.
Continued sleep loss resulted in greater pulse transit time reduction following spontaneous arousals in females but not in males.
The study used overnight polysomnography at multiple timepoints to analyze cardiovascular responses to spontaneous arousals across sleep restriction and normal sleep conditions.
Augmented cardiovascular responses to spontaneous nocturnal arousals following sleep restriction were more evident in females than in males, providing a potential mechanism for sex-specific cardiovascular disease risk.
This research suggests that losing sleep over multiple nights affects the heart and blood vessels differently in women compared to men. The study enrolled 19 healthy young adults (8 women, 11 men) and had them undergo two 16-day stays in a research facility — one where they were restricted to only 4 hours of sleep per night, and one where they were allowed a normal 9 hours. Researchers measured heart rate and pulse transit time (a measure of blood vessel responsiveness) whenever participants had brief, spontaneous awakenings during the night. After about 5 days of sleep restriction there were no notable differences, but after 11 days of restricted sleep, women showed significantly greater changes in both heart rate and blood vessel responses during these nighttime awakenings compared to men. The key finding is that prolonged sleep loss caused women's blood vessels to react more strongly to brief nighttime arousals than men's did. Pulse transit time, which reflects how quickly blood pulses travel through the arteries and can indicate vascular constriction, dropped more and for longer in women after sleep restriction. This type of repeated overnight cardiovascular stress — happening many times each night over weeks or months of short sleep — could contribute to the increased heart disease risk that has been observed in women who habitually sleep fewer hours. This research suggests a biological mechanism that may help explain why women who chronically get too little sleep appear to face a heightened risk of cardiovascular problems compared to men in similar situations. The findings highlight that sleep's relationship with heart health may not be the same for everyone, and that women's cardiovascular systems may be particularly sensitive to the effects of sustained sleep curtailment. These results come from a controlled laboratory study of young healthy adults, so future research will be needed to understand how these findings apply to older populations and to real-world patterns of sleep loss.
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Upload Your LabsGreenlund I, Covassin N, Bukartyk J, St Louis E, Calvin A, Somers V. (2026). Heart rate and vascular responses to spontaneous arousals following experimental sleep restriction.. American journal of physiology. Heart and circulatory physiology. https://doi.org/10.1152/ajpheart.00123.2026