Physical activity level (PAL) is associated with all-cause mortality in the elderly. However, few studies have attempted to clarify the relationship between lifestyle and PAL in the elderly. This study aimed to examine the determinants of PAL in the elderly in terms of behavioral patterns and exercise intensity, and to validate the simplified physical activity record (sPAR).

This study evaluated the validity of the total energy expenditure (TEE) estimated using uniaxial (ACCuni) and triaxial (ACCtri) accelerometers in the elderly. Thirty-two healthy elderly (64–87 years) participated in this study. TEE was measured using the doubly labeled water (DLW) method (TEEDLW). TEEACCuni (6.79 ± 1.08 MJ day−1) was significantly lower than TEEDLW (7.85 ± 1.54 MJ day−1) and showed wider limits of agreement (−3.15 to 1.12 MJ day−1) with a smaller correlation coefficient (r = 0.703). TEEACCtri (7.88 ± 1.27 MJ day−1) did not differ from TEEDLW and showed narrower limits of agreement (−1.64 to 1.72 MJ day−1) with a larger correlation coefficient (r = 0.835, P < 0.001). The estimated intensities of light activities were significantly lower with ACCuni. Greater mediolateral acceleration was observed during 6-min walk tests. The results suggest that ACCtri is a better choice than ACCuni for assessing TEE in the elderly.

Some researchers have reported that long-range correlations in the fluctuations of gait cycle duration brake down in the elderly gait, and functional impairment of the central nervous system (CNS) has been thought to be responsible for the reduced long-range correlations. PURPOSE: To reveal the origin of deteriorated long-range correlations, we hypothesized that declines in physical ability as well as alterations in CNS were responsible for altered long-range correlations of gait in the elderly. METHODS: 15 healthy old adults aged 64–79 yr were recruited. The subjects walked around a 34.2 m oval walkway in ‘fast’ speed for six minutes. Heel contact timing of each stride was obtained from foot switches attached to the insole in both shoes. The subjects stepped on the same spot for six minutes on force platforms. Foot contact timing was measured from vertical force on the platforms. Fractal scaling exponents (?) which evaluate long-range correlations in gait and stepping were calculated with a fractal analysis method, detrended fluctuation analysis (DFA). Range of motion (ROM) of neck, waist, hip, knee, and ankle joints were measured. Isokinetic joint torque of hip, knee, and ankle joints were measured with Cybex Dynamometer. Flection and extension torques of each joint were measured. Functional reach test was used for measuring subjects' ability to maintain balance. RESULTS: Reduced α in gait was significantly (p < 0.05) correlated with reduced ROM in hip extension, knee extension, ankle external and internal rotation, and marginally correlated with reduced ROM in waist rotation (p = 0.056). Reduced α in stepping was significantly correlated with reduced ROM in neck lateroflection, hip external and internal rotation, abduction, and flection. It also significantly correlated with joint torque in knee flection and extention, and ankle dorsiflection. Reduced functional reach range was significantly correlated with reduced α in both gait and stepping. CONCLUSIONS: Deteriorated long-range correlations in both gait and stepping were correlated with declined physical abilities, and additionally, each correlated with different items of physical ability decline. The result implies a strong relationship existing between declined physical ability and deteriorated long-range correlations of gait and stepping cycle.

Physical activity level (PAL) can be measured by using doubly labeled water (DLW) with measurement of basal metabolic rate (BMR). PAL is strongly associated with lower risk of mortality in healthy older adults (Manini et al, 2006). The cost of the aerobic training program is offset by a compensatory decline in non-exercise-associated thermogenesis (NEAT) in the elderly. NEAT may be the major determinant of body composition and nutrition status as well as PAL. PURPOSE: To examine the relationship between PAL, lifestyle, nutrition and body composition in the healthy community-dwelling elderly and in the frail elderly in the care house. METHODS: Thirty-two healthy elderly (14 men and 18 women, 64-87yr) and 16 frail elderly (8 men and 8 women, 67–96 yr) were participated in this study. Total energy expenditure (TEE) was measured by using DLW with intercept and multipoint method for 14 days. BMR was measured by using an indirect calorimeter in the morning after 10 h fasting with overnight staying. PAL was calculated as TEE divided by BMR. A tri-axial accelerometer (Matsushita Electric Works Ltd.) attached to an elastic belt was worn at the back of the waist. Daily activities during 24 hours were recorded by using simplified physical activity record. Each activity was divided by modality and intensity of the activities. Body composition was measured by using segmental bioelectrical impedance analysis. Diet was recorded with notes, cameras and scales. RESULTS: PAL was not significantly related to age and maintained until 80 years old. The inverse correlation between PAL estimated by tri-axial accelerometer and percent body fat was observed. The fraction of daytime on the activities of 2–4 METs exercise intensity was significantly correlated with PAL. The fraction of daytime on the exercise was not significantly correlated with PAL, and the fraction on the light-intensity daily activities was significantly correlated with PAL. The resting time was significantly and inversely correlated with PAL. CONCLUSIONS: Non-exercise daily activities with 2–4 METs intensity, such as housekeeping, gardening and several hobbies, are the major determinant PAL in the elderly.