Oral Presentation The Annual Scientific Meeting of the Endocrine Society of Australia and the Society for Reproductive Biology 2012

Salivary alpha amylase (sAA) response to psychological stress in lean and overweight/obese men (#62)

Sisitha U Jayasinghe 1 , Susan J Torres 1 , Emma Townsin 1 , Caryl A Nowson 1 , Alan J Tilbrook 2 , Anne I Turner 1
  1. Centre for Physical Activity and Nutrition, Deakin University, Burwood, VIC, Australia
  2. Livestock and Farming Systems, University of Adelaide, Roseworthy, SA, Australia

We have shown in humans that overweight/obesity does not affect salivary cortisol responses to psychological stress(1). Nevertheless, it is unknown if there are differences between lean and overweight/obese men in the activity of the sympatho-adrenal medullary system in response to psychological stress. The activity of the sympatho-adrenal medullary system can be ascertained by measuring salivary alpha amylase (sAA)(2). We tested the hypothesis that overweight/obese men will have a greater sAA response to psychological stress compared to lean men.

Lean (BMI=20-25kgm-2; n=19) and overweight/obese (BMI=27-35kgm-2; n=17) men (50-70 years) were subjected to a well characterised psychological stress (Trier Social Stress Test; TSST) at 3pm. Saliva samples were collected every 7-15min from 2pm-5pm.  Concentrations of sAA were determined by a kinetic assay and were compared within and between groups using repeated measures ANOVA.

BMI, body weight, percentage body fat, resting systolic and diastolic blood pressures were significantly (p<0.05) higherin overweight/obese men compared to lean men. Both groups responded to the TSST with a significant(p<0.05) elevation of sAA (overweight/obese=111% increase, lean=138% increase) but this response did not differ significantly between lean and overweight/obese men (time*treatment, p=0.261). There were no significant differences between lean and overweight/obese men in pre-treatment sAA concentrations (112.1±16.1vs140.8±16.5U/ml, respectively), delta sAA (155.1±51.2vs156.9±31.0U/ml, respectively), peak sAA concentration during stress (267.3±55.5vs297.7±41.0U/ml, respectively) or area under the curve (5220.5±2735.1vs3130.7±1525.4U/ml/min, respectively) (p>0.05 for all).

Both groups had a substantial but similar sAA response to psychological stress. The results did not support the hypothesis that overweight/obese men will have a greater sAA response to psychological stress compared to lean men. Our data suggest that elevated sympatho-adrenal medullary system responses to acute psychological stress (measured by sAA) may not be a major mechanism that increases the risk of overweight/obese men developing stress-related disease. Further research is required to verify this.1 2 

  1. Jayasinghe SU, Torres SJ, Townsin E, Nowson CA, Tilbrook AJ, Turner AI (2010) Salivary cortisol responses to acute psychological stress in lean and overweight/obese men Proceedings of the Australian Health and Medical Research Congress 5: 507
  2. Nater UM, La Marca R, Florin L, Moses A, Langhans W, Koller MM & Ehlert U (2006) Stress-induced changes in human salivary alpha-amylase activity-associations with adrenergic activity, Psychoneuroendocrinology 31: 49-58