Even mild sleep deprivation can lead to cardiovascular health risks for women
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Healthy women who delayed their normal bedtime by 1.5 hours showed endothelial dysfunction, which increases risk for cardiovascular disease, according to a study published in Annals of the American Thoracic Society.
“Our findings provide first biological evidence that postponing your bedtime by as little as 1 to 2 hours, which is a widespread behavior in this era of social media, damages vascular health,” Sanja Jelic, MD, director of the Center for Sleep Medicine and professor of medicine at Columbia University Medical Center, told Healio. “Over time, such early damage from insufficient sleep may lead to cardiovascular disease.”
In a randomized crossover clinical trial, Jelic and colleagues analyzed 35 healthy women (mean age, 36 ± 14 years; BMI, 25 ± 3 kg/m2; 51% white) who slept for 7 to 9 hours daily to determine if sleep deprivation (SD) causes endothelial dysfunction, which can in turn raise the risk for cardiovascular disease.
Researchers conducted the study in two parts. First, they randomly assigned the women to either a 6-week adequate sleep (AS) phase, which was based on their bedtime and wake time from actigraphy screening results taken 2 weeks prior to randomization, or a 6-week SD phase in which their bedtime was postponed by 1.5 hours, but their wake time remained the same as at baseline. After this study period, there was a 6-week span without intervention followed by another 6-week period in which participants followed the oppositive sleep phase from the one they had before.
Researchers used a linear mixed-effect model to assess differences in brachial artery flow-mediated dilation (FMD) between the groups, which served as the study’s primary outcome. They additionally assessed messenger ribonucleic acid expression of endothelial nitric oxide synthase (eNOS) and inflammation in endothelial cells (ECs).
Of the total cohort, 32 women had data for both the AS and SD study phases; the remaining three women only finished the AS phase.
Following comparable baseline measurements of brachial artery diameter, researchers found that SD lowered brachial artery FMD compared with AS (mean, 7.35% ± 2.15% vs. 8.65% ± 2.42%; P = .02).
In assessing secondary outcomes, researchers observed that SD was linked to a lower rate of the messenger ribonucleic acid expression of eNOS (0.4 ± 0.37 FC vs. 1 ± 1.76 FC).
When evaluating ECs they collected for inflammation, researchers found SD increased endothelial nuclear factor kappa B nuclear florescence area by 87% (mean, 2.04 ± 2.16 m2 vs. 1.09 ± 0.52 m2; P = .01).
“We were surprised at the consistency of detrimental effects on blood vessel (vascular) function after a relatively mild sleep deprivation in completely healthy women,” Jelic told Healio.
Jelic added that sleep needs to be addressed in everyday practice.
“Asking about sleep habits and counseling on the importance of sufficient sleep should be a routine part of health care encounters,” Jelic said.
“In the future, it is important to study the molecular mechanisms mediating these changes so that new therapies could be developed to target vascular damage in the setting of sleep deprivation,” she added.
For more information:
Sanja Jelic, MD, can be reached at sj366@cumc.columbia.edu.