Blood Pressure Levels and Pattern of Melatonin Secretion in a Population of Resident Physicians on Duty Niveles de presión arterial y el patrón de secreción de la melatonina en una población de médicos internos residentes de guardia

For a doctor, being on call typically involves stress and fatigue associated with moments of anxiety and sleeplessness. Resident physicians (MIR) are on call more than 4 times per month and during those periods may have to work for 24 h at a stretch. Several studies have associated being on call with increased cardiovascular risk, and alteration in blood pressure (BP) is one of the causal mechanisms. Physiological oscillations of a function over 24 h are known as the circadian rhythm (CR). Blood pressure decreases during night-time resting. 17.0 statistical package (Chicago, Illinois) was used for all statistical analysis. Data with a normal distribution are presented as means standard deviations and nonnormally distributed data as medians. Continuous variables were compared using Student’s t test or Mann-Whitney U. In all tests, P was considered significant at <.05. Residents’ mean age was 28 2.1 years. On a normal working day, systolic and diastolic BP decreased significantly between day and night-time readings (119 10.9 and 77 5.4 vs 108 7.6 mmHg and 67 6.1, P=.003). Furthermore, 6-SO4MEL values showed that CR was maintained during normal working hours, with concentrations being higher in the morning (8.00) than at night (0.00) (48.6 [28.1 to 74.1] vs 12.4 [7.7 to 38.9] ng/ml, P<.023) (Figure). When samples taken when residents were on call for 24 h were analyzed, there were no statistically significant differences between day and night-time values for systolic and diastolic BP (121 9.9 and 81 6.3 vs 116 11.3 and 73 7.3 mmHg, P=.08). Analysis of 6-SO4MEL values showed that CR was lost during the on-call work day, with values of 61.2 [43.7 to 89] at 8:00 am compared to 21.2 [14.4 to 75.2] ng/ml at Scientific letters / Rev Esp Cardiol. 2012;65(6):571–580 576 Document downloaded from http://www.revespcardiol.org, day 23/06/2017. This copy is for personal use. Any transmission of this document by any media or format is strictly prohibited.