Effect of the stress of medical residency training on the overnight dexamethasone suppression test

Forty-two medical residents and interns were studied to evaluate the effect of the stress of medical residency training on-call nights on the hypothalamic-pituitary-adrenal axis. Dexamethasone 1 mg was given at 11:00 p.m. on two separate occasions; a control (off-call) night and on on-call night. Plasma cortisol was measured between 8:00-9:00 a.m. the following morning. The number of patient admissions during the on-call night and the number of hours of sleep during both on-call and control nights were recorded. Plasma cortisol decreased to < 138 nmol/l (< 5 micrograms/dl) in 41 out of 42 (97.6%) of the participants following an on-call day and in 40 out of 42 (95.2%) participants after the control day. The number of hours of sleep during the on-call night was 3.9 +/- 0.29 and during the control night 7.0 +/- 0.11 hours and the number of patient admissions was 3.1 +/- 0.3. In conclusion General Internal Medicine on-call experience does not produce significant alteration on the hypothalamic-pituitary-adrenal axis.