Use of a resting control day in measuring the cortisol response to mental stress: diurnal patterns, time of day, and gender effects.
In laboratory studies of individual differences in stress reactivity, cortisol responses are typically measured by comparing a prestress baseline with values obtained at the end of the stressor. In the present study, we measured cortisol in this manner on a stress day, but we also took samples on a second day when the volunteers rested in the lab at the same time of day and for the same duration. We compared stress responses as the difference from pre- to poststress and also poststress vs. rest day control. The latter method allowed a greater appreciation of how stress perturbed the underlying diurnal baseline. Although the effect of stress was statistically significant when measured as the change from pre- to poststress, the magnitude of the effect was 54% larger when measured against the time-of-day control from the rest day. In particular the diurnal control method provided a wider range of stress values that potentially provide a greater range of response values in carrying out analyses of individual differences.
Behavioral Sciences Laboratories, Veterans Affairs Medical Center, Oklahoma City, OK 73190, USA. bill@mindbody1.org
William R
WR
Lovallo
Noha H
NH
Farag
Andrea S
AS
Vincent
D000222:Adaptation, Physiological / Q000502:physiology; D000293:Adolescent; D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis / Q000378:metabolism*; D008297:Male; D012146:Rest / Q000502:physiology*; D012463:Saliva / Q000737:chemistry / Q000378:metabolism; D012727:Sex Characteristics; D013315:Stress, Psychological / Q000378:metabolism* / Q000503:physiopathology; D013997:Time Factors; D055815:Young Adult
D006854:Hydrocortisone