Physical activity level and physical functionality in nonagenarians compared to individuals aged 60-74 years

Background. Functional dependence and the risks of disability increase with age. The loss of independence is thought to be partially due to a decrease in physical activity. However, in populations, accurate measurement of physical activity is challenging and may not provide information on functional impairment. Methods. This study therefore assessed physical functionality and physical activity level in a group of nonagenarians (11 men/11 women; 93 +/- 1 years, 66.6 +/- 2.4 kg, body mass index [BMI] = 24 +/- 1 kg/m(2)) and a group of participants aged 60-74 years (17 men/15 women; 70 +/- 1 years, 83.3 +/- 3.0 kg, BMI = 29 +/- 1 kg/m(2)) from the Louisiana Healthy Aging Study. Physical activity level was calculated from total energy expenditure (TEE) and resting metabolic rate (RMR). Physical functionality was assessed using the Reduced Continuous Scale Physical Functional Performance Test (CS-PFP10). Results. Nonagenarians had lower absolute (p < .001) and adjusted (p < .007) TEE compared to participants aged 60-74 years which was attributed to a reduction in both RMR and physical activity level. Nonagenarians also had reduced functional performance (p < .001) which was correlated with activity level (r = 0.68, p < .001). Conclusions. When compared to individuals aged 60-74 years, 73% of the reduction in TEE in nonagenarians can be attributed to a reduction in physical activity level, the remaining being accounted for by a reduction in RMR. The reduced physical activity in nonagenarians is associated with less physical functionality. This study provides the first objective comparison of physical functionality and actual levels of physical activity in older individuals.