Cortisol, alpha amylase, blood pressure and heart rate responses to food intake in men aged 50–70 years: importance of adiposity

Background: Increased adiposity is often associated with over activation of the hypothalamo-pituitary adrenal axis (HPA axis) and the sympatho-adrenal medullary system (SAM system) and excessive activation of these pathways in response to physiological challenges may be linked with the development of diseases. We tested the hypothesis that overweight/obese men aged 50–70 years will have greater HPA axis and SAM system responses to food intake compared with age matched lean men.

Lean (Body Mass Index; BMI = 20-25 kg/m2; n = 19) and overweight/obese (BMI = 27-35 kg/m2; n = 17) men (50–70 years) made their own lunch using standardised ingredients at 1200 h. Concentrations of cortisol and alpha amylase were measured in saliva samples collected every 15 min from 1145 h-1400 h with the exception of during lunch (1215 h) where no sample was collected. Blood pressures and heart rate were measured at 1145 h and every 15 minutes between 1245 h and 1400 h.

Results: Overweight/obese men had significantly higher body weight, BMI, percentage body fat and waist and hip circumferences compared to lean men (p < 0.001 for all). The meal consumed by the participants consisted of 22% protein, 53% carbohydrates and 25% fat. Overweight/obese men responded to lunch with a significant increase in cortisol whereas lean men did not show such an increase (time*treatment p = 0.008). There were no significant differences between the groups in the salivary alpha amylase response to the meal (time*treatment p = 0.195) or in SBP, DBP, MAP or HR responses (time*treatment p = 0.726, 0.898, 0.713, 0.620, respectively).

Conclusions: While men with a moderate level of overweight/obesity had a significant HPA axis response (as measured by salivary cortisol) to a standardised lunch, lean men had no HPA axis response. Lean and overweight/obese men had similar increases in SAM system activity (as measured by salivary alpha amylase) in response to the meal.