Workplace Standing Desks and Arterial Stiffness

Many jobs in today’s society require sitting at a desk with little physical activity. Individuals who engage in ten hours of sedentary behavior per day double their CVD risk. Standing desks are thought to decrease sedentary time and improve cardiovascular health. Acute use of standing desks is shown to lower PWV. However, chronic effects remain unknown. Forty eight participants qualified as seated (19 females, 5 males: age 41 ± 2 years, BMI 25 ± 1 kg/m2) or standing (21 females, 3 males: age 45 ± 2 years, BMI 25 ± 1 kg/m2) groups based on habitual workplace use. Arterial stiffness was assessed as pulse wave velocity (PWV) by using applanation tonometry in conjunction with electrocardiography. No differences were detected in carotid-femoral PWV (cfPWV) between seated and standing groups (p = 0.47). However, age (p \u3c 0.01), aerobic fitness (p \u3c 0.01), and fat percentage (p = 0.02) classifications revealed significant differences between groups. Standing for 50% of a workday does not affect cfPWV. Although, cardiorespiratory fitness and healthy body composition are associated with less arterial stiffness

Sex differences in self-report anxiety and sleep quality during COVID-19 stay-at-home orders

Background: COVID-19 and home isolation has impacted quality of life, but the perceived impact on anxiety and sleep remains equivocal. The purpose of this study was to assess the impact of COVID-19 and stay-at-home orders on self-report anxiety and sleep quality, with a focus on sex differences. We hypothesized that the COVID-19 pandemic would be associated with increased anxiety and decreased sleep quality, with stronger associations in women. Methods: One hundred three participants (61 female, 38 ± 1 years) reported perceived changes in anxiety and sleep quality due to stay-at-home orders during the COVID-19 pandemic and were administered the Spielberger State-Trait Anxiety Inventory (STAI), Pittsburgh Sleep Quality Index (PSQI), and Insomnia Severity Index (ISI). Chi-square and T test analyses were utilized to assess sex differences in reported anxiety and sleep. Analysis of covariance was used to compare the associations between reported impact of COVID-19 and anxiety/sleep parameters. Results: Women (80.3%) reported higher prevalence of increased general anxiety due to COVID-19 when compared to men (50%; p = 0.001) and elevated STAI state anxiety compared to men (43 ± 1 vs. 38 ± 1 a.u., p = 0.007). Despite these differences in anxiety, the perceived impact of COVID-19 on PSQI was not different between sexes. However, when stratified by perceived changes in anxiety due to COVID-19, participants with higher anxiety responses to COVID-19 had higher ISI compared to those with no perceived changes in anxiety (9 ± 1 vs. 5 ± 1 a.u., p = 0.003). Additionally, participants who reported reduced sleep quality due to COVID-19 reported higher state anxiety (45 ± 1 a.u.) compared to those that perceived no change (36 ± 2 a.u., p = 0.002) or increased (36 ± 2 a.u., p \u3c 0.001) sleep quality. Conclusion: COVID-19 and state-ordered home isolation was associated with higher anxiety and reduced sleep quality, with a stronger association in women with respect to anxiety

Sex differences in blood pressure responsiveness to spontaneous K-complexes during stage II sleep

K-complexes are a key marker of nonrapid eye movement sleep, specifically during stages II sleep. Recent evidence suggests the heart rate responses to a K-complexes may differ between men and women. The purpose of this study was to compare beat-to-beat blood pressure responses to K-complexes in men and women. We hypothesized that the pressor response following a spontaneous K-complex would be augmented in men compared with women. Ten men [age: 23 ± 2 yr, body mass index (BMI): 28 ± 4 kg/m ] and ten women (age: 23 ± 5 yr, BMI: 25 ± 4 kg/m ) were equipped with overnight finger plethysmography and standard 10-lead polysomnography. Hemodynamic responses to a spontaneous K-complex during stable stage II sleep were quantified for 10 consecutive cardiac cycles, and measurements included systolic arterial pressure (SAP), diastolic arterial pressure (DAP), and heart rate. K-complex elicited greater pressor responses in men when blood pressures were expressed as SAP (cardiac cycle sex: P = 0.007) and DAP (cardiac cycle sex: P = 0.004). Heart rate trended to be different between men and women (cardiac cycle sex: P = 0.078). These findings suggest a divergent pressor response between men and women following a spontaneous K-complex during normal stage II sleep. These findings could contribute to sex-specific differences in cardiovascular risk that exist between men and women. NEW & NOTEWORTHY K-complexes during stage II sleep have been shown to elicit acute increases in blood pressure and heart rate, but the role of sex (i.e., male vs. female) in this response is unclear. In the present study, we demonstrate that the pressor response following spontaneous K-complexes were augmented in men compared to age-matched women. The augmented blood pressure reactivity to spontaneous K-complexes during stage II sleep in men advance the field of cardiovascular sex differences, with implications for nocturnal blood pressure control

Effects of alcohol on sleep and nocturnal heart rate: Relationships to intoxication and morning-after effects

Background: Alcohol consumption produces feelings of well-being and stimulation, but also impairs psychomotor performance, disturbs cardiovascular function and sleep, and can disrupt next-day mood and behavior. A deeper understanding of how the acute effects of alcohol relate to its sleep and morning-after effects is needed to minimize harm resulting from its use. This study examined relationships between the effects of a high dose of alcohol on subjective and psychomotor measures, nocturnal heart rate, sleep quality, and morning-after mood and behavior. We hypothesized that alcohol would produce disturbances in cardiovascular and sleep regulation during the night, which would predict morning-after mood and behavioral performance. Methods: Thirty-one men and women participated in two overnight laboratory visits during which they consumed either alcohol (1.0 g/kg for men, 0.85 g/kg for women) or placebo (randomized, crossover design). They consumed the beverage from 8 to 9 pm, and remained in the laboratory overnight for polysomnographic sleep recording. Subjective and behavioral measures were obtained during consumption and at 7–8 am the morning after. Results: Alcohol increased both negative and positive arousal, urge to drink and sedation, and it impaired performance on behavioral tasks. During sleep, alcohol produced expected tachycardia and detriments in sleep quality including decreased total sleep time, sleep efficiency, and altered sleep architecture. Only modest effects on mood or performance were detected the following morning. The acute sedative-like effects of alcohol were related to increases in N2 sleep, but not to other disruptions in sleep or nocturnal heart rate, and neither sleep impairments nor nocturnal heart rate were related to mood or task performance the morning after. Conclusions: The effects of alcohol on sleep and nocturnal heart rate were not strongly related to either its acute or morning-after effects. These findings do not provide strong support for the idea that alcohol-induced sleep disruptions underlie morning-after effects.</p

Subjective and objective sleep differ in male and female collegiate athletes.

BACKGROUND/PURPOSE: Despite the importance of sleep for athletic performance, there is a lack of normative sleep data and sex comparisons in collegiate athletes. The primary purpose of our study was to assess the prevalence of insufficient sleep in collegiate athletes, with a secondary aim to compare male and female athletes. PROCEDURES: Participants included 121 collegiate athletes (65 men and 56 women) from six team sports and three individual sports. Subjective assessments of sleep included at-home sleep diary, Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), and Insomnia Severity Index (ISI). Objective assessments of sleep included three consecutive off-season weekdays of wrist actigraphy to assess total sleep time (TST) and sleep efficiency (SE). MAIN FINDINGS: Actigraphy revealed that 94% of student-athletes received/night, while 61% received/night. Subjective assessments revealed that 35% had PSQI \u3e5, 28% had ISI scores \u3e7, and 19% had ESS scores \u3e10. Objective TST was not different between sexes (6.7±0.1 vs. 6.7±0.1 hours, p=0.99), but females demonstrated higher SE (87±1 vs. 82±1%, p CONCLUSIONS: The majority of male and female collegiate athletes received less than age-recommended levels of sleep, and 44% subjectively reported poor sleep quality, mild severity insomnia, and/or excessive daytime sleepiness. Sex differences were observed in male and female collegiate athletes

Effects of alcohol on sleep and nocturnal heart rate: relationships to intoxication and morning-after effects.

BACKGROUND Alcohol consumption produces feelings of well-being and stimulation, but also impairs psychomotor performance, disturbs cardiovascular function and sleep, and can disrupt next-day mood and behavior. A deeper understanding of how the acute effects of alcohol relate to its sleep and morning-after effects is needed to minimize harm resulting from its use. This study examined relationships between the effects of a high dose of alcohol on subjective and psychomotor measures, nocturnal heart rate, sleep quality, and morning-after mood and behavior. We hypothesized that alcohol would produce disturbances in cardiovascular and sleep regulation during the night, which would predict morning-after mood and behavioral performance. METHODS Thirty-one men and women participated in two overnight laboratory visits during which they consumed either alcohol (1.0 g/kg for men, 0.85 g/kg for women) or placebo (randomized, crossover design). They consumed the beverage from 8 to 9 pm, and remained in the laboratory overnight for polysomnographic sleep recording. Subjective and behavioral measures were obtained during consumption and at 7-8 am the morning after. RESULTS Alcohol increased both negative and positive arousal, urge to drink and sedation, and it impaired performance on behavioral tasks. During sleep, alcohol produced expected tachycardia and detriments in sleep quality including decreased total sleep time, sleep efficiency, and altered sleep architecture. Only modest effects on mood or performance were detected the following morning. The acute sedative-like effects of alcohol were related to increases in N2 sleep, but not to other disruptions in sleep or nocturnal heart rate, and neither sleep impairments nor nocturnal heart rate were related to mood or task performance the morning after. CONCLUSIONS The effects of alcohol on sleep and nocturnal heart rate were not strongly related to either its acute or morning-after effects. These findings do not provide strong support for the idea that alcohol-induced sleep disruptions underlie morning-after effects

0223 Total sleep deprivation and pain perception during cold noxious stimuli in older adults

Introduction Our laboratory has previously reported an augmented pain response to 24-hour total sleep deprivation (TSD) in young men and women. Because aging is associated with a greater prevalence of chronic pain and diminished sleep quality, we hypothesized TSD would increase pain perception to the cold pressor test (CPT) in older adults. Furthermore, we hypothesized this relationship would be stronger in postmenopausal women compared to age-matched men. Methods Eighteen participants (9 women) between 55 and 75 years were tested once after 24-hour TSD and once after normal sleep (NS) using a randomized, cross-over design. Following a supine baseline, subjects performed a 2-min CPT by immersing their left hand in water (0-3ºC). Perceived pain was recorded every 15 seconds during simultaneous recordings of muscle sympathetic nerve activity (MSNA; microneurography). Results Age (61±2 vs. 60±1 years) and BMI (26±1 vs. 27±1 kg/m2) were not different between women and men, respectively. CPT elicited a graded increase of perceived pain (time, p0.05). The condition effect was also observed when pain was expressed as mean change from baseline (NS, Δ6.9 ± 2.4 vs. TSD, Δ8.2 ± 2.4 a.u.; p=0.041) and peak change from baseline (NS, Δ8.4 ± 2.7 vs. TSD, Δ9.7 ± 2.5 a.u.; p=0.039). Changes in pain were correlated with changes in MSNA during the initial 30 seconds of CPT during both NS (r=0.513; p =0.025) and TSD (r=0.528; p=0.020). Conclusion TSD significantly augments perceived pain during cold noxious stimuli in older adults. Contrary to our initial hypothesis, this increased pain perception is not significantly different between men and women. Sympathetic reactivity during the initial phase of CPT was associated with changes in pain, but the clinical relevance of this relationship remains unclear. Our findings support the concept of sleep as a cost effective, therapeutic strategy for reducing pain in older men and women

0069 Spectral analyses of slow wave sleep and rapid eye movement sleep are associated with changes in continuous nocturnal blood pressure

Introduction Slow wave (SWS) and rapid eye movement (REM) sleep are both associated with dynamic changes in nocturnal blood pressure (BP). Specifically, SWS is often associated with the greatest reductions of nocturnal BP, while episodic increases of BP are a hallmark of REM sleep. While it is widely assumed that the respective intensities of SWS and REM impact nocturnal BP, definitive studies examining these intensities via spectral analysis during continuously recorded BP are lacking. Moreover, while increases of alpha frequencies (i.e., alpha intrusion) during REM are reported in some pathological conditions, the relation between alpha intrusion and REM BP is unknown. Methods Thirteen participants (6 female, 22±1 years, 28±1 kg/m2) were equipped with overnight finger plethysmography (NOVA, Finapres) and standard 10-lead polysomnography. Central and occipital leads were analyzed using a short-term Fourier transform function to quantify 1) delta density using delta frequencies (0.5-4 Hz) in the first and second SWS cycles and 2) alpha intrusion using alpha frequencies (8-12 Hz) in the final REM episode. Continuous systolic arterial pressure (SAP), diastolic arterial pressure (DAP), and heart rate (HR) were recorded during wake and sleep. Results BP was significantly reduced during the first (SAP, 114±4 to 99±4 mmHg; DAP, 68±3 to 57±3 mmHg; p0.05), cycle of SWS when compared to wake. Changes in delta density across the SWS stages were significantly correlated with changes in SAP (r =-0.69, p=0.03) and DAP (r=-0.71, p=0.02). During REM, acute episodes of alpha intrusion were associated with increases of SAP (119±5 mmHg to 123±5 mmHg; p=0.039) and DAP (69±5 mmHg to 72±5 mmHg; p=0.043), but not HR. Conclusion Our findings suggest that the intensity of SWS is associated with greater reductions in nocturnal BP, and that episodes of alpha intrusion increase REM BP. These findings support growing evidence that both SWS and REM are important to cardiovascular health

Chronic standing desk use and arterial stiffness

Background: Sedentary activity and sitting for at least 10 hours per day can increase the risk for cardiovascular disease by more than 60%. Use of standing desks may decrease sedentary time and improve cardiovascular health. Acute standing lowers pulse wave velocity (PWV), but chronic effects remain unknown. The purpose of this study was to determine the effect of chronic standing desk use on arterial stiffness versus seated controls. Methods: A total of 48 adults participated in this study. Twenty-four participants qualified as seated desk users (age 41 [10] y, body mass index 25 [4] kg/m2) and 24 as standing desk users (age 45 [12] y, body mass index 25 [5] kg/m2). Arterial stiffness was assessed as PWV within the aorta, arm, and leg. Results: Carotid–femoral PWV (cfPWV) was not different between seated (6.6 [1.3] m/s) and standing (6.9 [1.3] m/s) groups (P = .47). Similarly, there were no differences in arm or leg PWV between groups (P = .13 and P = .66, respectively). A secondary analysis of traditional factors of age and aerobic fitness revealed significant differences in cfPWV in seated and standing desk participants. Age also significantly influenced cfPWV across conditions. Conclusions: Standing for \u3e50% of a workday did not affect PWV. Consistent with previous research, fitness and age are important modulators of arterial stiffness

0220 Total sleep deprivation decreases cardiac vagal activity

Introduction Acute 24-hour total sleep deprivation (TSD) elicits a consistent hypertensive response in both men and women. In contrast, divergent sympathetic neural responses to TSD have been reported in men and women, with greater sympathetic predominance in women. Given the previously reported divergence of sympathetic outflow observed between men and women, we hypothesized that TSD would elicit altered cardiac vagal control across sexes. Methods We examined 28 participants (14 men, 22 ± 1 years, 26 ± 1 kg/m2; 14 women, 22 ± 1 years, 23 ± 1 kg/m2) between the ages of 18 to 40 years. Participants were studied twice, once after 24-hour TSD and once after normal sleep (randomized, cross-over design). We recorded heart rate (electrocardiography) and beat-by-beat blood pressure (finger plethysmography) during 5-min supine, awake rest. Vagal-cardiac activity was assessed with a Fourier transform and quantified as normalized high frequency (HF; 0.15-0.4 Hz), and cardiovagal baroreflex sensitivity (BRS) was assessed with up-up (vagal activation) and down-down (vagal withdrawal) sequence analyses. Results TSD decreased normalized HF in men (0.41 ± 0.05 to 0.33 ± 0.05 n.u.) and women (0.53 ± 0.03 to 0.44 ± 0.03 n.u.; condition p\u3c0.01), but these responses were not different between sexes (condition × sex, p\u3e0.05). Secondary analysis of up-up and down-down sequencing revealed no difference in cardiovagal BRS. Conclusion TSD elicits significant reduction of normalized HF in men and women, but these responses were not different between sexes. Our findings provide additional insight into the complex relations between sleep deprivation, autonomic activity, and hypertension