High levels of cardiorespiratory fitness and/or habitual physical activity are associated with reduced risk of cardiovascular disease. The responsible mechanisms are multifarious, but effects on insulin sensitivity are likely to play an important role. The purpose of this review is to highlight some recent evidence on the interrelationships between physical activity, fitness, obesity, genotype and insulin resistance.
Effects on cardiorespiratory fitness and abdominal obesity are both likely to contribute to the insulin-sensitizing effects of regular physical activity. Recent data suggest that at least in older adults, the intensity of an exercise intervention may influence the magnitude of changes in insulin sensitivity, and emerging data suggest that individual changes in insulin sensitivity following an exercise programme may, in part, be influenced by genotype.
Increasing physical activity reduces insulin resistance. As both intensity of exercise and genetic factors may modulate the magnitude of this effect, current physical activity for health guidelines that emphasize engagement in moderate-intensity physical activity in a ‘one-size-fits-all’ approach may need revision in the future to optimize the potential benefits accrued from individuals becoming more active.
Institute of Diet, Exercise and Lifestyle (IDEAL), Institute of Biomedical and Life Sciences, University of Glasgow, UK
Correspondence to Dr Jason M.R. Gill, Institute of Diet, Exercise and Lifestyle (IDEAL), Institute of Biomedical and Life Sciences, West Medical Building, University of Glasgow, Glasgow, G12 8QQ, UK Tel: +44 141 3302916; fax: +44 141 3302923; e-mail: firstname.lastname@example.org