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

Consistent sleep patterns are associated with better cardiovascular health, while 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-hour total sleep deprivation. Sixteen healthy adults (10 females, 6 males; 34 ± 9 years; 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 1-2-week 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 to habitual sleep (0.96 ± 0.24 to 0.51 ± 0.24 hours, p<0.0001). Peak RH was unaltered by consistent sleep (main effect for condition: 27 ± 9 to 28 ± 5 mL/100mL/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.