Author(s): SCHWENDINGER, F., INFANGER, D., LICHTENSTEIN, E., HINRICHS, T., KNAIER, R., ROWLANDS, A.V., SCHMIDT-TRUCKSÄSS, A., Institution: UNIVERSITY OF BASEL, Country: SWITZERLAND, Abstract-ID: 1274

INTRODUCTION:
Accelerometer-assessed physical activity (PA) is associated with mortality (Rowlands et al., 2021). Recent developments make it possible to parse the relative contributions of intensity and volume of PA to a given health outcome (Schwendinger et al., 2023). It is currently unclear whether PA intensity, duration, or a combination of both is the driving factor for longevity. This study investigates how intensity, duration, and volume of PA contribute to all-cause and cardiovascular disease mortality in the US adult population.
METHODS:
Adult participants of the 2011–2014 National Health and Nutrition Examination Survey Study (N=7518 in final analyses) wore accelerometers for 7 days on their wrists (Johnson et al., 2014). The volume, intensity distribution, and duration of 24-hour PA behaviour were described by average acceleration (AvAcc), intensity gradient (IG), and daily time spent active, respectively. Weighted Cox proportional hazards models estimated the mortality risk associated with these PA metrics.
RESULTS:
Both IG and AvAcc demonstrated inverse curvilinear dose-response relationships with all-cause mortality, with IG showing a slightly better model fit compared to AvAcc alone, the combination of IG and AvAcc, or when PA duration was included. Desirable values of IG and AvAcc lie approximately between -2.7 to -2.5 and 35-45 mg, respectively as risk reduction plateaued above these ranges. For cardiovascular disease mortality, an inverse curvilinear association was observed with IG, but not with AvAcc. Representative reference values for IG and AvAcc were produced.
CONCLUSION:
The intensity of PA is central to longevity with PA volume playing a secondary role, especially for cardiovascular disease mortality. The established age- and sex-specific reference values for intensity and volume of PA, informed by the dose-response relationship with mortality, provide desirable PA benchmarks.

REFERENCES:
Johnson, C. L., Dohrmann, S. M., Burt, V. L., & Mohadjer, L. K. (2014). National health and nutrition examination survey: sample design, 2011-2014. Vital and Health Statistics, Series 2 (162):1-33.
Rowlands, A., Davies, M., Dempsey, P., Edwardson, C., Razieh, C., & Yates, T. (2021). Wrist-worn accelerometers: recommending ~1.0 mg as the minimum clinically important difference (MCID) in daily average acceleration for inactive adults. Br J Sports Med, 55(14), 814-815. https://doi.org/10.1136/bjsports-2020-102293
Schwendinger F., Wagner J., Knaier R., Infanger D., V. Rowlands A. V., Hinrichs T., & Schmidt-Trucksäss A. (2023). Accelerometer metrics: healthy adult reference values, associations with cardiorespiratory fitness, and clinical implications. Med Sci Sports Exerc, 56(2):170-80. https://doi.org/10.1249/MSS.0000000000003299