Peer-Reviewed
Is the cortisol awaking response associated with psychological stress?
D.B. O'Connor
Colworth Science Park
L. Dye
Colworth Science Park
H. Hendrick
Colworth Science Park
D. Talbot
Colworth Science Park
T. Dadd
Colworth Science Park
A. Mayes
Colworth Science Park
J. Powell
Colworth Science Park
Background
The cortisol awaking response (CAR) is defined as the cortisol secretory activity in the first 45-60 minutes immediately post-awakening. It has been suggested that this response may play a significant role in the regulatory balance of the immune system and that psychological factors may disrupt the normal awakening response. Recent research has shown that psychological stress may influence the magnitude of the CAR, however the findings have been mixed. This study examined the impact of chronic stress on the CAR.
Method
119 healthy female participants were recruited experiencing high or low stress based upon their scores on the perceived stress scale (high >14, n=70/low stress <=14, n=48). Salivary cortisol levels were measured immediately upon awakening (0, 15, 20, & 45 minutes) and at 3, 6, 9 and 12 hours on two consecutive days. Age and waist-hip-ratio were also measured. The area under the curve (AURC) estimate was used as the measure of overall cortisol secretory activity post-awakening.
Results
The findings showed that the magnitude of the CAR was significantly lower in the high stress group compared to the low stress group (p=.023) indicating that participants who experienced high stress exhibited a “blunted” CAR. The diurnal mean was also lower for the high stress than for the low stress group (p=0.056). Age was a significant covariate, no effect of waist-hip-ratio was observed.
Discussion
These results suggest that psychological stress is associated with a “blunted” CAR and a lower diurnal mean in women. These findings may have important broader implications for future health risk, the regulation of the immune system and the development of stress management interventions.
