The Relationship Between Sleep Duration Standard Deviation and Blood Pressure at Rest and During Exercise in Postmenopausal Females with Hypertension

Background: In healthy populations, increased sleep variability is associated with increased blood pressure (BP) at rest and during submaximal exercise. However, majority of investigations have focused on males and mixed sex-samples potentially complicating the generalizability of these findings to clinical and female populations. The purpose of this investigation was to determine if sleep variability is associated with BP at rest and during submaximal exercise in postmenopausal females with hypertension (HTN). We hypothesize high sleep variability will be associated with higher BP at rest and during exercise in postmenopausal females with HTN. Methods: Forty-two postmenopausal females with HTN, both medicated and non-medicated (68±7yrs), were recruited. HTN was confirmed across two visits scheduled 2-3 hours post-awakening. BP was measured bilaterally after 10-min of seated rest until three readings within 5 mmHg were obtained. Average resting systolic (SBP), diastolic (DBP) and mean arterial pressure (MAP) were calculated from both arms. HTN was defined as a SBP of 130-179 mmHg without medications or 120-179 mmHg with medications and/or a DBP of 80-109 mmHg with or without medications. Participants wore a wrist activity monitor for a minimum of seven consecutive days to determine average sleeping patterns. Participants then completed a clinical exercise stress test utilizing a modified Bruce protocol. Manual BPs were obtained during the last minute of each stage by a trained clinician with submaximal SBPs identified from stage 1. Sleep variability was calculated as the within subject standard deviation (SD) of mean sleep duration from the monitor wear. Normality was checked using a Shapiro-Wilk test. Associations between sleep duration SD and resting SBP, DBP, MAP, and submaximal SBP, were analyzed using general linear models, adjusted for medication status, body mass index (BMI), sleep apnea status, and average sleep duration. Results: 86% of participants were medicated for BP and 17% reported having sleep apnea. Group data are reported as mean±SD. BP (in mmHg) at rest was 137±13 for SBP, 79±10 for DBP, 98±10 for MAP, and 166±18 for submaximal SBP. BMI was 31.3±5.2 kg/m 2 and sleep duration SD was 60±23 min. For BPs, the overall model for resting DBP was significant (R 2 =0.300, F(5,36)=3.082, P =0.020), while SBP or MAP at rest (R 2 =0.081, F(5,36)=0.636, P =0.674; R 2 =0.207, F(5,36)=1.878, P =0.123) and submaximal SBP (R 2 =0.135, F(5,36)=1.123, P =0.366) were not. Sleep duration SD was significantly associated with DBP (β=0.506, P =0.002) with all other covariates nonsignificant ( P >0.05). Conclusion: These findings suggest that greater sleep duration SD is significantly associated with higher DBP at rest in postmenopausal females with HTN, independent of mean sleep duration, BMI, medication status, and sleep apnea. These results highlight the potential impact of sleep variability on resting cardiovascular health in postmenopausal females. Supported by NHLBI grant R56HL164575 This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.