Relationships between older adults' use of time and cardio-respiratory fitness, obesity and cardio-metabolic risk: A compositional isotemporal substitution analysis.

Older adults' health has been linked with time in moderate-to-vigorous physical activity (MVPA), and recent studies suggest time in sedentary behaviour may also be important. Time-use behaviours (MVPA, light physical activity, sedentary time and sleep) are co-dependent, and therefore their associations with health should be examined in an integrated manner. This is the first study to investigate the relationship between older adults' reallocation of time among these time-use behaviours and markers of cardio-respiratory fitness, obesity and cardio-metabolic risk. Cross-sectional study of 122 Australians (65 ± 3 y, 61% female). Daily time use: average daily minutes spent in MVPA, light physical activity, sedentary time and sleep derived from 24-h, 7-day accelerometry, were conceptualised as a time-use composition. Cardio-respiratory fitness: graded submaximal cycle ergometer test. Obesity: objectively measured body mass index (BMI) and waist-to-hip ratio (WHR). Cardio-metabolic risk: sphygmomanometer-measured resting blood pressure and fingertip blood sampling for fasting total cholesterol and glucose. Time-use composition was significantly associated with obesity markers (BMI, p = 0.001; WHR, p < 0.001). The reallocation of 15 min to MVPA from any of the other behaviours was associated with approximately +1.1 (95% confidence interval 0.2; 1.9) ml/kg-1 min-1 VO2max, -0.7 (-1.0; -0.3) BMI units and -1.2 (-1.8; -0.7) WHR percentage points, while the opposite reallocation (15 min from MVPA to other behaviours) was associated with larger difference estimates of -1.8 (-3.2; -0.4) ml/kg-1 min-1 VO2max, +1.2 (0.5; 1.9) BMI units and +2.1 (1.2; 3.1) WHR percentage points. These findings reinforce the importance of MVPA for health among older adults. Interventions to maintain MVPA, even without increasing it, may be valuable.

Dumuid D ，Lewis LK ，Olds TS ，Maher C ，Bondarenko C ，Norton L ... -  《-》

Moderate activity and fitness, not sedentary time, are independently associated with cardio-metabolic risk in U.S. adults aged 18-49.

van der Velde JH ，Savelberg HH ，Schaper NC ，Koster A ... -  《-》

Health outcomes associated with reallocations of time between sleep, sedentary behaviour, and physical activity: a systematic scoping review of isotemporal substitution studies.

Grgic J ，Dumuid D ，Bengoechea EG ，Shrestha N ，Bauman A ，Olds T ，Pedisic Z ... -  《International Journal of Behavioral Nutrition and Physical Activity》

Associations between sleep duration, sedentary time, physical activity, and health indicators among Canadian children and youth using compositional analyses.

Carson V ，Tremblay MS ，Chaput JP ，Chastin SF ... -  《-》

Compositional analysis of the associations between 24-h movement behaviours and cardio-metabolic risk factors in overweight and obese adults with pre-diabetes from the PREVIEW study: cross-sectional baseline analysis.

Swindell N ，Rees P ，Fogelholm M ，Drummen M ，MacDonald I ，Martinez JA ，Navas-Carretero S ，Handjieva-Darlenska T ，Boyadjieva N ，Bogdanov G ，Poppitt SD ，Gant N ，Silvestre MP ，Brand-Miller J ，Schlicht W ，Muirhead R ，Brodie S ，Tikkanen H ，Jalo E ，Westerterp-Plantenga M ，Adam T ，Vestentoft PS ，Larsen TM ，Raben A ，Stratton G ... -  《International Journal of Behavioral Nutrition and Physical Activity》