ARS | Publication request: Effects of exercise on mobility limitation in obese and non-obese older adults

Submitted to: Obesity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 6, 2009
Publication Date: April 20, 2010
Citation: Manini, T.M., Newman, A.B., Fielding, R.A., Blair, S.N., Perri, M.G., Anton, S.A., Goodpaster, B.H., Katula, J., Rejeski, W., Kritchevsky, S., Hsu, F., Pahor, M. 2010. Effects of exercise on mobility limitation in obese and non-obese older adults. Obesity. 18(6):1168-1175.

Interpretive Summary: As the life expectancy in the United States has continued to rise, the maintenance of physical and cognitive independence of older Americans has emerged as a major clinical and public health priority. A critical factor in an older person’s ability to function independently is mobility, or the ability to move without assistance. Several studies suggest that regular physical activity may improve physical performance, but definitive evidence showing that mobility disability can be prevented is lacking. We conducted "Lifestyle Interventions and Independence For Elders-LIFE" pilot study. We examined how obesity (BMI greater than or equal to 30) influenced the response to this physical activity intervention. We assessed the effect of a comprehensive physical activity (PA) intervention on the short physical performance battery (SPPB) and other physical performance measures in obese and non-obese individuals. A total of 424 sedentary persons at risk of disability and in the age range of 70-89 years were followed for an average of 1.2 years. Participants were assigned to a Moderate intensity PA intervention compared to a successful aging (SA) health education intervention. Non-obese participants in the PA group had significant increases in 400 meter walking speed (+1.5%), while their counterparts in the SA group declined (-4.3%). Obese individuals declined regardless of their assigned intervention group (PA: -3.1%; SA: -4.9%). SPPB scores increased following PA in obese (PA: +13.5%; SA: +2.5%) and non-obese older adults (PA: +18.6%; SA: +6.1%), but this increase was less in the obese. This study shows that a PA intervention improved the SPPB score and other measures of physical performance in obese and non-obese older individuals but that these positive benefits were reduced by excess body weight.

Technical Abstract: Background: Coupled with an aging society, the rising obesity prevalence is likely to increase the future rates of physical disability. We set out to determine whether the effects of a physical activity intervention aimed to improve mobility function in older adults is modified by obesity. Methods: Older adults at risk for disability (N = 424, age range: 70-88 years) were randomized to a 12 month physical activity (PA) group involving moderate intensity aerobic, strength, balance and flexibility exercise (150 min per week) or a successful aging (SA) group who attended weekly educational workshops. Groups were further stratified by obesity levels using a body mass index ' 30 (n = 179). Mobility function was assessed as usual walking speed over 400 meters and scores on a short physical performance battery (SPPB), which includes short distance walking, balance tests and chair rises. Results: Over 12 months of supervised training, the attendance and total amount of walking time was similar between obese and non-obese subjects and no weight change was observed. Non-obese participants in the PA group had significant increases in 400 meter walking speed (+1.5%), while their counterparts in the SA group declined (-4.3%). Obese individuals declined regardless of their assigned intervention group (PA: -3.1%; SA: -4.9%). SPPB scores increased following PA in obese (PA: +13.5%; SA: +2.5%) and non-obese older adults (PA: +18.6%; SA: +6.1%), but this increase was attenuated in the obese. Conclusion: A moderate intensity PA intervention improves physical function in obese and non-obese older adults, but these positive benefits are attenuated by excess body mass.