The effects of a graduated aerobic exercise programme on cardiovascular disease risk factors in the NHS workplace: a randomised controlled trial

BACKGROUND: Sufficient levels of physical activity provide cardio-protective benefit. However within developed society sedentary work and inflexible working hours promotes physical inactivity. Consequently to ensure a healthy workforce there is a requirement for exercise strategies adaptable to occupational time constraint. This study examined the effect of a 12 week aerobic exercise training intervention programme implemented during working hours on the cardiovascular profile of a sedentary hospital workforce. METHODS: Twenty healthy, sedentary full-time staff members of the North West London Hospital Trust cytology unit were randomly assigned to an exercise (n = 12; mean ± SD age 41 ± 8 years, body mass 69 ± 12 kg) or control (n = 8; mean ± SD age 42 ± 8 years, body mass 69 ± 12 kg) group. The exercise group was prescribed a progressive aerobic exercise-training programme to be performed 4 times a week for 8 weeks (initial intensity 65% peak oxygen consumption (VO(2 peak))) and to be conducted without further advice for another 4 weeks. The control was instructed to maintain their current physical activity level. Oxygen economy at 2 minutes (2minVO(2)), 4 minutes (4minVO(2)), VO(2 peak), systolic blood pressure (SBP), diastolic blood pressure (DBP), BMI, C-reactive protein (CRP), fasting glucose (GLU) and total cholesterol (TC) were determined in both groups pre-intervention and at 4 week intervals. Both groups completed a weekly Leisure Time Questionnaire to quantify additional exercise load. RESULTS: The exercise group demonstrated an increase from baseline for VO(2 peak )at week 4 (5.8 ± 6.3 %) and 8 (5.0 ± 8.7 %) (P < 0.05). 2minVO(2 )was reduced from baseline at week 4 (-10.2 ± 10.3 %), 8 (-16.8 ± 10.6 %) and 12 (-15.1 ± 8.7 %), and 4minVO(2 )at week 8 (-10.7 ± 7.9 %) and 12 (-6.8 ± 9.2) (P < 0.05). There was also a reduction from baseline in CRP at week 4 (-0.4 ± 0.6 mg·L(-1)) and 8 (-0.9 ± 0.8 mg·L(-1)) (P < 0.05). The control group showed no such improvements. CONCLUSION: This is the first objectively monitored RCT to show that moderate exercise can be successfully incorporated into working hours, to significantly improve physical capacity and cardiovascular health.