Sleep duration regularity, but not sleep duration, is associated with microvascular function in college students

Abstract

Study Objectives Vascular dysfunction is a hypothesized mechanism linking poor sleep habits to an increased incidence of cardiovascular diseases. However, the vascular profile associated with free-living sleep duration and sleep regularity has not been well elucidated, particularly in young adults. Thus, this study aimed to evaluate the associations between mean sleep duration, regularity in sleep duration, and peripheral vascular function in young adult college students. Methods Fifty-one healthy undergraduate students (20±1 years) completed 14 days of 24-hour wrist actigraphy and subsequent vascular assessments. Macrovascular function was measured using brachial artery flow-mediated dilation (FMD) while microvascular function was measured via passive leg movement (PLM). Results Mean sleep duration was unrelated to FMD and PLM. Conversely, more irregular sleep duration (14-day sleep duration standard deviation [SD]) was unfavorably associated with all three measures of PLM-induced hyperemia (peak leg blood flow [LBF], p=0.01; change in LBF from baseline to peak, p<0.01; LBF area under the curve, p<0.01), and remained significant in regression models which adjusted for sex, body mass index, blood pressure, physical activity, alcohol and caffeine consumption, and sleep duration (all p<0.05). When using a median split to dichotomize “low” and “high” sleep duration SD groups, those demonstrating high variability in sleep duration exhibited ~45% lower PLM responses compared to those demonstrating low variability. Conclusions Irregular sleep duration is associated with poorer microvascular function as early as young adulthood. These findings support the growing body of evidence that irregular sleep patterns may be an independent and modifiable risk factor for cardiovascular disease.

Sleep variability and regularity as contributors to obesity and cardiometabolic health in adolescence

“…Although the emerging evidence collected in this review shows an association between intraindividual day-to-day deviations in the dura- [26]. On a positive note, most studies reviewed herein did record actigraphy data for 7 [32, 33, 46-49, 62, 69, 71, 73, 75, 77, 84, 87, 90] to 14 [85] days, as suggested by Fischer and colleagues [26]. Future studies should analyze their parameters and select the most accurate generalizable metric (or metrics) to understand which is most predictive for obesity, cardiovascular, and metabolic outcomes.…”

“…Evidence also suggests that sleep variability directly affects the vascular system, as Hoopes and colleagues examined the association between sleep variability on peripheral vascular function in 51 healthy young adults [85]. Their research showed that sleep variability is associated with poorer microvascular function, even after adjusting for sex, BMI, blood pressure, physical activity, average sleep duration, and alcohol and caffeine use [85]. More specifically, those individuals who were categorized as having high sleep variability (after researchers conducted a median split) experienced 45% less robust passive leg movement (which is a marker of resistance artery microvascular function) compared with those with low sleep variability [85].…”

“…Their research showed that sleep variability is associated with poorer microvascular function, even after adjusting for sex, BMI, blood pressure, physical activity, average sleep duration, and alcohol and caffeine use [85]. More specifically, those individuals who were categorized as having high sleep variability (after researchers conducted a median split) experienced 45% less robust passive leg movement (which is a marker of resistance artery microvascular function) compared with those with low sleep variability [85]. Additionally, Rodríguez-Col on and colleagues found that each hour increase in sleep variability was associated with a À 0.14, À0.12, and À 0.16-millisecond 2 decrease in power in the total, daytime, and nighttime highfrequency range in the electrocardiogram (ECG), respectively, an indication of impaired heart rate variability in adolescents [49]; decreased heart rate variability is a marker of cardiac autonomic balance and a risk factor for CVD that is suggestive of a dysregulation in the balance between the sympathetic and parasympathetic nervous system [86].…”

The association between electronic cigarettes, sleep duration, and the adverse cardiovascular outcomes: Findings from behavioral risk factor surveillance system, 2020

“…A recent mendelian randomization analysis indicated that there is a U-shaped effect of sleep duration on CVD based on data collected from 404,044 UK Biobank participants ( 33 ). Another US study showed that irregular sleep duration is associated with poorer microvascular health in young college students ( 34 ). It should be noted that inappropriate sleep patterns can also elevate the risk of CVD among young adults, which should have the lowest risk for CVD.…”

Consistency where it counts: Sleep regularity is associated with circulating white blood cell count in young adults

“…Indeed, irregular sleep-wake patterns have been independently linked to cardiometabolic morbidities and risk factors including metabolic syndrome ( Huang and Redline, 2019 ), hypertension ( Brindle et al., 2019 ), adiposity ( Ogilvie et al., 2016 ), and insulin resistance ( Taylor et al., 2016 ) in midlife or later. Albeit less frequently examined, youth and young adults with irregular sleep patterns also tend to have poorer cardiometabolic health, such as increased adiposity ( Nicholson et al., 2020 ; He et al., 2015 ), impaired microvascular function, ( Hoopes et al., 2021 ) and poorer diet ( Ogilvie et al., 2018 ) when compared to those with regular sleep patterns. Our findings also parallel two studies reporting independent associations between sleep duration SD and elevated C-reactive protein in children ( Nielsen et al., 2016 ) and adolescents ( Park et al., 2016 ).…”