Abstract 411: Diurnal Variation of Blood Pressure in Medical Residents: MARINE 1 (Measures of Active Residents in Numerous Environments)
Residency training subjects healthy young people to frequent fluctuation in sleep-wake cycles. Although shift work is known to increase cardiovascular risk, little is known about the physiology of phase-shifted sleep in residency. This study uses 24-hr ambulatory blood pressure monitoring to investigate diurnal BP variation in medical residents working alternating day/night periods. We hypothesized that diurnal variation of BP is dependent upon sleep/wake status, not upon day/night hours.
Residents were recruited from the Johns Hopkins Medicine Residency Program during the 2013-2014 academic year. Thirty-six individuals participated while working in three clinical environments (intensive care unit, general medicine wards, outpatient clinic), and during various sleep-wake schedules (night shift, 24-hr overnight call, day shift). BP was measured every 30 min during waking hours and every 2 hr during sleep. Residents self-reported during which hours they slept. Ninety-eight separate 24-hr periods of data were collected (Table 1).
There is no difference in mean 24-hr SBP, awake SBP/DBP, or asleep SBP/DBP between those working different schedules. However, there are statistically significant differences in day SBP/DBP and night SBP/DBP between participants working different schedules. In all schedules, participants showed at least a 9 mmHg drop in SBP between awake and asleep. Diurnal variation of BP in this population is present, and dependent upon sleep/wake status, not day/night hours. Further investigation into the correlation between this reversal of diurnal BP variation and cardiovascular outcomes in shift workers is warranted.
Author Disclosures: L. Brown: None. J. Chaisson: None. H. Cheng: None. W. Labaki: None. O. Cingolani: None. S. Schulman: None. S. Desai: None.
- © 2014 by American Heart Association, Inc.