Effects of 12 months aerobic exercise intervention on work ability, need for recovery, productivity and rating of exertion among cleaners: a worksite RCT

PURPOSE: This study assessed the effects of a worksite aerobic exercise intervention among cleaners on: work ability, need for recovery, productivity, and rating of exertion. METHODS: In a monocentric randomised controlled trial in Denmark, 116, of 250 invited, cleaners were cluster-randomised (work location; sex; age; length of service) to aerobic exercise [N = 57, 44.9 years, 75.4% female, body mass index (BMI) 26.2], receiving 2 weekly aerobic exercise sessions during 12 months, or a reference group (N = 59, 45.7 years, 76.3% female, BMI 27.1), receiving health-promoting lectures. Self-reported data on outcomes and sociodemographic information were collected at baseline, and at 4 and 12 month follow-up. All outcomes were analysed in a linear repeated-measures 2 × 2 mixed-model by an intention-to-treat analysis approach. RESULTS: Drop-out was 26 and 33% at 4 and 12 months, respectively. Aerobic exercise adherence was 51% during the first 4 months. At 4 month follow-up no effects were found. At 12 month follow-up, work ability significantly increased by 0.59 on a 0–10 scale (95% CI 0.05–1.13) and need for recovery significantly decreased by − 11.0 on a 0–100 scale (95% CI − 19.8 to − 2.2) in the aerobic exercise group compared to the reference group. Productivity and rating of exertion were unaltered. Analysis stratified on age showed significant effects only among the participants aged ≤ 45 years. CONCLUSIONS: After 12 months work ability improved and need for recovery decreased. A period of 4 months was insufficient to affect these outcomes emphasising that longer interventions may be needed to induce effects on work ability and need for recovery.