The effect of physical activity on psychological distress, cortisol and obesity: results of the farming fit intervention program

BACKGROUND Rural and regional Australians have a higher likelihood of mental illness throughout their lifetime than people living in major cities, although the underlying reasons are not yet well defined. Additionally, rural populations experience more lifestyle associated co-morbidities including obesity, diabetes and cardiovascular disease. Research conducted by the National Centre for Farmer Health between 2004 and 2009 revealed a positive correlation between obesity and psychological distress among the farming community. Chronic stress is known to overstimulate the regulation of the hypothalamic-pituitary-adrenal (HPA) axis and cortisol secretion which are associated with abdominal adiposity. Increasing physical activity may normalise cortisol secretion and thereby positively impact both physical and mental health. This paper assesses the effects of increasing physical activity on obesity, health behaviors and mental health in Victorian farming men and women. METHODS Farming Fit was a six month quasi-experimental (convenience sample) longitudinal design control-intervention study. Overweight or obese (BMI ≥25 kg/m2) farm men (n = 43) and women (n = 29) were recruited with demographic, health behaviors, anthropometric, blood pressure and biochemistry data collected at baseline and at a six months. Salivary cortisol and depression anxiety stress scale results were collected at baseline, three and six months. The intervention group (n = 37) received a personalized exercise program and regular phone coaching to promote physical activity. RESULTS The intervention group showed significant reductions in body weight and waist circumference. Results indicated that following the six month exercise program, the intervention group were 2.64 ± 0.65 kg lighter (p < 0.001), had reduced waist circumference by 2.01 ± 0.86 cm (p = 0.02) and BMI by 0.97 ± 0.22 kg/m2 (p < 0.001) relative to the control group. CONCLUSION Increasing physical activity altered measures of obesity in farm men and women but did not affect mental health measures or cortisol secretion levels. TRIAL REGISTRATION ACTRN12610000827033.