THURSDAY, April 16, 2026 (HealthDay News) -- Working double shifts is associated with alterations in normal cortisol patterns, according to a study published online April 8 in Nursing Open.
Fadime Ulupınar, R.N., from Erzurum Technical University in Turkey, and colleagues examined the effects of single- versus double-shift work schedules on salivary cortisol concentrations among nurses. The analysis included 52 female nurses, with saliva cortisol samples collected before, after, and at midnight for both a single and a double shift.
The researchers found significant effects for both time and shift type. Salivary cortisol concentrations were highest between 7:30 and 8:30 a.m., with trough levels recorded at midnight. Double-shift workers showed higher mean cortisol concentrations, with cortisol levels nearly twofold higher at midnight in double-shift workers than single-shift workers. There was also a significant interaction effect between time and shift type.
"Our findings indicate that extended shift schedules may be associated with alterations in the circadian pattern of cortisol, reflecting increased physiological strain in nurses working prolonged hours," Ulupınar said in a statement.