Women with difficulty falling, staying asleep at risk of hypertension

Symptoms of insomnia may be associated with an elevated risk of hypertension in women.

In a large study, women with shorter sleep duration were more likely to have incident hypertension compared with those who slept 7–8 hours (≤5 hours: hazard ratio [HR], 1.10, 95 percent confidence interval [CI], 1.05–1.16; 6 hours: HR, 1.07, 95 percent CI, 1.03–1.10). But this risk increase was not seen for women with longer sleep duration (9 hours: HR, 1.03, 95 percent CI, 0.97–1.10; >9 hours: HR, 1.08, 95 percent CI, 0.94–1.23). [Hypertension 2023;doi:10.1161/HYPERTENSIONAHA.123.21350]

Women who sometimes or usually had difficulty falling or staying asleep were also at increased risk of developing hypertension compared with those who rarely had these sleep difficulties (HR, 1.14, 95 percent CI, 1.11–1.17 and HR, 1.28, 95 percent CI, 1.22–1.35, respectively; p<0.001 for trend).

Waking up early in the morning was not a risk factor for hypertension (p=0.722 for trend). Of note, the association of short sleep duration and sleeping difficulties with hypertension remained significant despite adjustments for shift work schedules (night vs day shifts) and chronotype (morningness vs eveningness).

The analysis was based on data from 66,122 Nurses’ Health Study 2 participants who were free of hypertension at baseline. A total of 25,987 incident cases of hypertension were documented over 16 years of follow-up.

“These findings suggest that individuals who struggle with symptoms of insomnia may be at risk of hypertension and could benefit from pre-emptive screening,” according to lead study author Dr Shahab Haghayegh, a research fellow at the Brigham and Harvard Medical School in Boston, Massachusetts, US.

How symptoms of insomnia contribute to an increased risk of hypertension is unknown. But Haghayegh pointed out that when people have trouble sleeping, it can set off a series of changes in their bodies such as increased sodium retention, arterial stiffness, and cardiac output, potentially leading to hypertension. Sleep disruptions can also affect blood vessel constriction/relaxation activity as well as the function of cells that regulate the vascular tone.

“Hypertension is associated with many other physical and mental health complications. The sooner we can identify individuals with high blood pressure and treat them for it, the better we can mitigate future health issues,” Haghayegh said.

The findings of the study do not establish causality but rather draw attention to the crucial role of quality sleep in people’s overall wellbeing, according to Haghayegh. “The American Academy of Sleep Medicine recommends sleeping 7 or more hours a night, and if you cannot fall or stay asleep, it might be worth exploring why that is.”

The next step in the study is to establish the mechanisms underlying the association exists and if sleep medications could have a beneficial effect on blood pressure, he said.

The study had several limitations. For the most part, the study population exclusively comprised women. Also, data on sleep quality were collected only at select time points throughout the study.