A pilot study : high intensity intermittent training to combat chronic stress in the New Zealand Police : a Master's thesis presented in partial fulfilment of the requirements for the degree of Masters of Sport and Exercise at Massey University, Wellington, New Zealand

Abstract

Background: Stress is increasingly being reported to be associated with immunosuppression, disease progression and psychological illness (Sergerstrom & Miller, 2004). Police are considered to be employed in a highly stressful occupation and due to this are at a heightened risk for developing negative chronic stress related disorders (de Terte & Stephens, 2014). There are known strategies to combat stress such as exercise. However, in moderately active individuals a more vigorous exercise programme is needed to reduce the effects of stress. High intensity intermittent training (HIIT) could be a potential stress reducing mechanism especially due to its success in treating obesity, weight loss and cardiac issues (Gibala, Little, MacDonald, & Hawley, 2012; Schoenfeld & Dawes, 2009). Aim: To see the effects of HIIT on chronic stress indices in the New Zealand Police. Method: Using three single case studies, this study employed a 10-week HIIT intervention measuring markers of stress such as Perceived Stress Scale scores, cortisol levels and associated blood immune markers at baseline and postintervention. Results: Chronically stressed police officers displayed high perceived stress scale scores and compromised immune functioning due to decreased cortisol secretion and increased eosinophil count. Post-intervention decreased perceived stress, normalised cortisol levels and reduced immune inflammation markers. Conclusion: High Intensity intermittent training decreases perceived chronic stress while also providing further evidence for the relationship between systemic inflammation and mental disease.