Work

Accelerometer Output and Oxygen Uptake in Adults With and Without Down Syndrome: METs vs. Percent VO2Reserve

Year: 2025

Type: article

Abstract: ABSTRACT Background The estimation of physical activity (PA) and sedentary behaviour with accelerometers is typically based on the relationship between accelerometer output and metabolic equivalents (METs)—an index of PA intensity. But for adults with Down syndrome (DS), PA intensity may be better reflected in the percent oxygen uptake reserve (%VO2Reserve), as it accounts for their lower aerobic fitness. This study examined if the relationship between accelerometer output and METs or %VO2Reserve across various PAs and sedentary behaviours differs between adults with and without DS. Methods Forty‐one adults with DS (age 35 ± 9 years; 18 women) and 41 adults without DS (age 24 ± 5 years; 18 women) performed 17 tasks of varying intensity. We estimated aerobic fitness with a submaximal treadmill test. We measured oxygen uptake with portable calorimetry and expressed it as METs and %VO2Reserve. Output from triaxial accelerometers on the nondominant hip and wrist was determined as Vector Magnitude (VM). We used multilevel modelling to evaluate the relationships of METs or %VO2Reserve with VM, controlling for body mass index (BMI) and age. Results For the hip accelerometer, VM and the group‐by‐VM interaction significantly predicted METs (p < 0.001; conditional R2 = 0.82), but between‐group differences were small. For the wrist accelerometer, VM and age significantly predicted METs (p < 0.035; conditional R2 = 0.76). For both the hip and the wrist accelerometer, VM, the group‐by‐VM interaction and BMI significantly predicted %VO2Reserve (p ≤ 0.047; conditional R2 = 0.82 and 0.74, respectively). Between‐group differences in the response to VM were larger for VO2Reserve than METs models. Conclusion The relationship between accelerometer output and %VO2Reserve across PAs and sedentary behaviours is different between adults with and without DS. Calibrating accelerometer output against %VO2Reserve may be preferable to METs.

Source: Journal of Intellectual Disability Research

DOI: 10.1111/jir.13253

Authors: S. Agiovlasitis, B. K. Ballenger, P. Choi, M. Haider, Q. Du, R. W. Motl

Institutions: Mississippi State University, Transylvania University, Sonoma State University, University of Illinois Chicago

Language: English

Topic: Physical Activity and Health

Subfield: Physiology

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: bronze

Funders: National Institutes of Health, Eunice Kennedy Shriver National Institute of Child Health and Human Development