Salivary cortisol, salivary alpha amylase and heart rate responses to psychological stress: Importance of adiposity in men

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 72-87-HPA Axis
Basic
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-82
Sisitha U Jayasinghe*1, Susan J Torres1, Emma Townsin1, Caryl A Nowson1, Alan J Tilbrook2 and Anne I Turner1
1Deakin University, Melbourne, Australia, 2South Australian Research & Deve, Roseworthy, SA, Australia
We have shown in sheep that increased adiposity is associated with increased cortisol reactivity to isolation restraint stress(1).  Nevertheless, it is not clear if increased adiposity is associated with higher hypothalamo-pituitary adrenal axis and sympatho-adrenal medullary system reactivity to psychological stress in humans.  We tested the hypothesis that overweight/obese men of 50-70 years will have a greater salivary cortisol, greater salivary alpha amylase (sAA) and an increased heart rate (HR) response to psychological stress compared with age matched lean men.

Lean (BMI=20-25 kg/m2; n=19) and overweight/obese (BMI=27-35 kg/m2; n=17) men (50-70 years) were subjected to a well characterised psychological stress (Trier Social Stress Test; TSST)(2) at 3pm. Concentrations of cortisol and sAA were measured in saliva samples collected every 7-15min from 2pm-5pm.  HR was measured using ECG around the same time points.  Cortisol and sAA concentrations and HR were compared within and between groups using repeated measures ANOVA.

Mean (±SEM) BMI, body weight, percentage body fat (measured using bio-electrical impedance), resting systolic and diastolic blood pressures were significantly higher (p<0.05) in overweight/obese men compared to lean men (30.6±0.6 vs 23.5±0.3 kg/m2, 93.8±2.3 vs 69.7±1.6 kg, 30.6±0.6 vs 20.2±1.1 %, 129.0±2.8 vs 119.1±3.3 mmHg, 74.5±2.0 vs 67.7±2.1 mmHg, respectively). Both groups responded to the TSST with a substantial elevation of cortisol (406%), sAA (197%) and HR (22%) but this response did not differ significantly between lean and overweight/obese men (time * treatment for cortisol, sAA and HR; p=0.187, p=0.288, p=0.550, respectively). There were no significant differences between lean and overweight/obese men in pre-treatment values, peak height, reactivity or area under the curve for cortisol, sAA or HR (p>0.05 for all).

While both groups had substantial responses to psychological stress, the results did not support the hypothesis that overweight/obese men will have a greater cortisol, sAA and HR responses to psychological stress compared to lean men.  This suggests that elevated hypothalamo-ptuitary adrenal axis (measured by cortisol) and sympatho-adrenal medullary system (measured by sAA and HR) responses to acute psychological stress may not be a major mechanism that increases the risk of overweight/obese men developing stress-related disease.

1.            Tilbrook AJ, Rivalland EAT, Turner AI, Lambert GW, Clarke IJ. Responses of the hypothalamopituitary adrenal axis and the sympathoadrenal system to isolation/restraint stress in sheep of different adiposity. Neuroendocrinology. 2008;87(4):193-205. 2.            Kirschbaum C, Pirke KM, Hellhammer DH. The Trier Social stress test - A tool for investigating psychobiological stress responses in a laboratory setting. Neuropsychobiology. 1993;28(1-2):76-81.

Nothing to Disclose: SUJ, SJT, ET, CAN, AJT, AIT

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: This research was funded by Deakin University.