Reduced sleep irregularity does not impact peripheral vascular function before or following total sleep deprivation.

Consistent sleep patterns are associated with better cardiovascular health, whereas sleep loss is known to impair vascular function. This study examined whether consistent sleep could improve vascular function and mitigate the negative effect of 25-h total sleep deprivation. Sixteen healthy adults [10 females, 6 males; 34 ± 9 yr; body mass index (BMI): 25 ± 3 kg/m²] completed a randomized crossover study involving two 12-night sleep conditions, habitual sleep, and a consistent sleep/wake schedule that were separated by a 1- to 2-wk washout. Sleep was tracked via wrist actigraphy. Vascular assessments were conducted after each sleep condition at baseline and after one night of total sleep deprivation. Forearm reactive hyperemia (RH) was measured using venous occlusion plethysmography. Blood pressure responses to static handgrip exercise and postexercise ischemia (PEI) were assessed using finger photoplethysmography. Consistent sleep reduced sleep irregularity (sleep duration standard deviation) as compared with habitual sleep (0.96 ± 0.24 to 0.51 ± 0.24 h, P < 0.0001). Peak RH was unaltered by consistent sleep (main effect for condition: 27 ± 9 to 28 ± 5 mL/100 mL/min, P = 0.53) and sleep deprivation reduced peak RH (main effect for time: 28 ± 7 to 25 ± 8 mL/100 mL/min, P = 0.004) with no interaction present between sleep conditions (P = 0.69). Resting blood pressure and blood pressure reactivity to handgrip exercise and PEI were unchanged by consistent sleep or total sleep deprivation (P > 0.05). These results find that a short-term reduction in sleep irregularity does not improve resting peripheral vascular function or diminish the decrease in peripheral vasodilation following total sleep deprivation.NEW & NOTEWORTHY We examined the effect of a short-term reduction in sleep duration irregularity on peripheral vascular function. Maintaining a consistent sleep schedule reduced sleep duration standard deviation (SD) but had no effect on peak reactive hyperemia in the forearm or blood pressure reactivity to sympathetic stimuli. One night of total sleep deprivation decreased peak reactive hyperemia in the forearm, an impairment that was not mitigated by consistent sleep behavior.