Background and aims South Asian people are at increased risk of type-2 diabetes (T2DM) compared to Europeans. Further, the health risks associated with T2DM are elevated in South Asians, and this may adversely influence exercise capacity. T2DM is associated with reduced exercise capacity and metabolic disturbances to skeletal muscle. We hypothesised that, in South Asian people, poor exercise capacity is associated with impaired skeletal muscle oxidative capacity. Materials and methods Participants in the Southall and Brent Revisited Study, a population-based cohort resident in UK comprised of Europeans and first generation South Asian and African-Caribbean migrants undertook a 6-minute stepper test. Near Infrared Spectroscopy (NIRS) was used to non-invasively assess skeletal muscle oxidative capacity using changes in oxygenated and deoxygenated haemoglobin concentrations during arterial occlusions at rest and post-exercise. Recovery time constants (Τ) were calculated; longer Τ represents poorer muscle oxidative capacity. Analysis was by multiple linear regression adjusted for age, gender and ethnicity. Results 183 participants (mean age=72±6 years, male=137) undertook the test. In multivariable models age, sex, T2DM and South Asian ethnicity were independent predictors of fewer steps. Participants with T2DM (n=34) completed fewer steps than people without (-48 steps, 95%CI=-72, -24, p<0.001). Compared to Europeans, South Asians achieved fewer steps (-32.4 steps, 95%CI=-53, -12, p=0.002) whereas African-Caribbeans achieved a similar number (-5.6 steps, 95%CI=-33, 22, p=0.7) after adjustment for presence of T2DM. In multivariable models only South Asian ethnicity was independently associated with Τ (Δ=10.1s, 95%CI=2.3, 17.9, p= 0.011 after adjustment). Differences in exercise capacity associated with T2DM and ethnicity were not attenuated when muscle oxidative capacity was included in models. Conclusion Exercise capacity is impaired in South Asian people independently of T2DM. Skeletal muscle oxidative capacity is impaired in South Asian people but this does not explain the reduction in exercise capacity.