The Effect of a 12 Week Mixed-Modality Training Intervention on the Cardio-Metabolic Health of Rotational Shift Workers

Abstract

Purpose To assess the effect of a 12 week resistance or aerobic training intervention on markers of cardio-metabolic function and sleep among male rotational shift workers. Method Thirty-eight sedentary, apparently healthy, male rotational shift workers were recruited and randomly allocated to a non-exercise control (CON) group, 3 sessions/week of moderate intensity continuous (MICT), or resistance training (RT) for 12 weeks in a semi-supervised setting. Pre- and post-testing assessed markers of cardio-metabolic function including peak oxygen uptake (VO 2peak ), glucose metabolism, insulin sensitivity, body composition, inflammatory markers, and 14 day actigraphy sleep assessment. Results Mean session attendance across the intervention was 25 (± 7) of a possible 36 sessions. A significant group by time interaction was observed for MICT, with lower c-reactive protein (CRP) values observed post-training ( P = 0.049). A significant effect for time was observed for both MICT ( n = 9; P = 0.04) and RT ( n = 10; P = 0.021), increasing total sleep time (TST) following a night shift post-intervention. Data redistribution regarding exercise adherence: < 24 (N-ADHERE) or ≥ 24 (ADHERE) resulted in significant pre-to-post reduction in body fat ( P = 0.024) and fat mass percentage ( P = 0.014) among ADHERE. No differences were observed for any intervention group on insulin sensitivity, glucose metabolism or oxygen uptake. Conclusion The results of the current study support exercise as a valid intervention to improve the cardio-metabolic health of rotational shift workers. Average sessional attendance suggests shift workers face barriers to exercise that may need to be addressed to improve health outcomes.

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