Physical Activity

Exposure Definition

Bodily movement produced by skeletal muscles that requires energy expenditure. Includes occupational, transport, household, and leisure-time activity. Measured by duration, intensity (e.g., METs), and frequency. Physical activity improves cardiorespiratory fitness, insulin sensitivity, and mental health; reduces risk of obesity, type 2 diabetes, cardiovascular disease, and some cancers. Sedentary behavior is a related but distinct exposure. Genetic variation in fitness and motivation may modify response to activity interventions.

Proxies

NameUnitMeasurementData source
Self-reported leisure-time activityminutes/week or MET-min/weekQuestionnaires (e.g., IPAQ)Surveys
Accelerometrycounts/min or mgWearable devicesCohort studies

Biological Systems Affected

cardiovascular

Improves endothelial function, blood pressure, lipid profile; reduces CAD and stroke risk

metabolic

Enhances insulin sensitivity; reduces T2D and obesity risk

musculoskeletal

Maintains bone density and muscle mass

Sensitive Developmental Windows

childhood and adolescence (5-24)

Establishes lifelong habits; bone and muscle development

GxE Highlights

GeneDiseaseDirectionEvidence type
ftoobesitybufferintervention
tcf7l2type-2-diabetesbufferliterature

Tissue-Specific Notes

skeletal muscle— glucose uptake; insulin sensitivity
adipose tissue— lipolysis; metabolic health

References

  1. 1.Warburton DER, Bredin SSD (2017). Physical activity and health. Lancet. doi:10.1016/S0140-6736(16)30570-8
  2. 2.Loos RJF, Kilpeläinen TO (2018). Gene–physical activity interactions in obesity and type 2 diabetes. Progress in Molecular Biology and Translational Science. doi:10.1016/bs.pmbts.2018.01.004