Work Ability, Physical Activity, and Cardiorespiratory Fitness: 2-year Results From Project Active

• Published in: Journal of occupational and environmental medicine 2000-09, Vol.42 (9), p.906-910
• Main Authors: Smolander, Juhani, Blair, Steven N., Kohl, Harold W.
• Format: Article
• Language: English
• Subjects: Adult; Aging; Biological and medical sciences; Body Weight; Counseling; Energy Metabolism; Exercise; Female; Health Promotion - methods; Humans; Life Style; Lifestyles; Male; Medical sciences; Middle Aged; ORIGINAL ARTICLES; Oxygen Consumption; Physical Fitness; Prevention and actions; Public health. Hygiene; Public health. Hygiene-occupational medicine; Specific populations (family, woman, child, elderly...); Work Capacity Evaluation; Workers
• ISSN: 1076-2752; 1536-5948
• DOI: 10.1097/00043764-200009000-00012

An adequate level of physical activity may maintain or promote work ability in aging workers. Project Active is a randomized trial comparing a Lifestyle physical activity program with a Structured exercise program in sedentary but healthy adults aged 35 to 60 years. Subjects in both groups received 6 months of intensive intervention followed by 18 months of active follow-up. The total number of subjects was 235, from which 80 subjects participated in the work ability assessment. Primary outcome measures were energy expenditure (kcal · kg⁻¹ · day⁻¹), cardiorespiratory fitness (peak oxygen uptake in ml· min⁻¹ · kg⁻¹), and the Work Ability Index. At 6 months, daily energy expenditure had increased significantly over baseline (mean ± SD, from 33.0 ± 0.9 to 34.4 ± 1.8 kcal · kg⁻¹ · day⁻¹) and was maintained over baseline at 24 months (34.0 ± 2.5 kcal · kg⁻¹ · day⁻¹). The significant increase in energy expenditure was observed particularly in moderate levels of activity. The average percentage of body fat was significantly higher a baseline compared with 6 months and 24 months. Peak oxygen uptake increased from baseline significantly during the first 6 months (from 29.6 ± 5.7 to 30.6 ± 6.3 ml · min⁻¹ · kg⁻¹) and decreased to the baseline level (29.1 ± 5.5 ml · min⁻¹ · kg⁻¹) at 24 months. At baseline, the average Work Ability Index was 44.2 ± 4.0, and it remained unchanged at 6 months (44.4 ± 3.9) and at 24 months (44.2 ± 3.1). In conclusion, a 2-year physical activity intervention increased daily energy expenditure, reduced body fat, and maintained peak oxygen uptake in healthy, middle-aged, sedentary subjects. The average Work Ability Index score at baseline was excellent and did not change during the 2-year physical activity interventions.