Sleep variability and cardiovascular health in undergraduate college students
| Author(s) | Katulka, Elissa K. | |
| Date Accessioned | 2020-10-22T12:34:15Z | |
| Date Available | 2020-10-22T12:34:15Z | |
| Publication Date | 2020 | |
| SWORD Update | 2020-09-06T16:03:30Z | |
| Abstract | Assessment of sleep duration has dominated sleep literature to date, providing substantial evidence that habitual insufficient sleep is an independent determinant of cardiometabolic disease risk. However, sleep is a multi-dimensional biological and behavioral construct which can be evaluated using additional metrics beyond habitual sleep duration alone. Additionally, evaluation of habitual sleep duration does not consider the fact that sleep is a human behavior which often varies from one night to the next. Experimental modeling of extreme fluctuations in sleep-wake patterns result in several suboptimal alterations to cardiovascular health and function. Further, emerging evidence in older adults has revealed that mild, free-living fluctuations in sleep timing and/or duration (i.e., sleep variability; SLV) are associated with increased incidence of cardiovascular and metabolic diseases. Importantly, young adults, and particularly college students, tend to display greater SLV when compared to older adults. However, it is currently unknown if associations between free-living SLV and pre-clinical indices of cardiovascular disease risk are apparent in young adults. Purpose: To evaluate the association between SLV metrics and pre-clinical indices of cardiovascular health in a sample of generally healthy, young adult undergraduate college students. Hypotheses: 1) SLV metrics will be directly, independently associated with circulating immune markers; 2) SLV metrics will be inversely, independently associated with nocturnal blood pressure (BP) dipping; and 3) SLV metrics will be inversely, independently associated with peripheral vascular function in undergraduate college students. Methods: SLV metrics (i.e., sleep duration standard deviation, sleep midpoint standard deviation) were objectively estimated using wrist accelerometry for 14 consecutive days and nights during the fall (2018, 2019) and spring (2019, 2020) academic semesters in 51 healthy, full-time undergraduate college students (20 ± 1 years; 20 M, 31 F). Following sleep monitoring, participants returned to the lab for a fasted blood sample and non-invasive evaluation of peripheral vascular function via passive leg movement (PLM). Participants also performed 24-hours of ambulatory BP monitoring following sleep monitoring. Results: Sleep duration variability was significantly associated with total white blood cell count (WBC; R-squared=0.28, p<0.01) and various WBC subtypes in undergraduate students. Sleep duration variability was also significantly, inversely associated with the peak leg blood flow (LBF; R-squared=0.13, p=0.01), change in LBF (R-squared=0.14, p<0.01), and LBF area under the curve during PLM (R-squared=0.14, p<0.01). Most of these associations remained significant after adjustment for appropriate biological and behavioral covariates. Conversely, SLV was not associated with nocturnal BP profile. Conclusion: Consistent with our hypothesis, free-living SLV, particularly sleep duration variability, is significantly associated with several pre-clinical indices of cardiovascular health in a sample of otherwise healthy undergraduate college students. These findings suggest that promotion of consistent sleep durations in young adulthood may be important for maintaining ideal cardiovascular health and could have potential implications for reducing the risk of cardiometabolic diseases that increases with age. | en_US |
| Advisor | Witman, Melissa A. H. | |
| Degree | Ph.D. | |
| Department | University of Delaware, Department of Kinesiology and Applied Physiology | |
| DOI | https://doi.org/10.58088/83me-az82 | |
| Unique Identifier | 1201254768 | |
| URL | https://udspace.udel.edu/handle/19716/27872 | |
| Language | en | |
| Publisher | University of Delaware | en_US |
| URI | https://login.udel.idm.oclc.org/login?url=https://www.proquest.com/docview/2447311187?accountid=10457 | |
| Keywords | cardiovascular health | en_US |
| Keywords | college students | en_US |
| Keywords | immune cell | en_US |
| Keywords | nocturnal blood pressure | en_US |
| Keywords | sleep health | en_US |
| Keywords | vascular function | en_US |
| Title | Sleep variability and cardiovascular health in undergraduate college students | en_US |
| Type | Thesis | en_US |