The capacity and hypoxic response of blood flow in human subcutaneous adipose tissue remains incompletely understood. In the present study we therefore measured adipose blood flow in nine healthy young men by positron emission tomography using radiowater tracer. Subcutaneous adipose blood flow was determined in adjacent to knee extensors at rest and during dynamic knee extensor exercise, and two physiological perturbations: while breathing moderate systemic hypoxia (14 O2) at rest and during exercise, and during intra-femoral infusion of adenosine, with a dose which has previously been shown to induce maximal thigh blood flow. Adipose tissue blood flow was 1.3 ± 0.6 ml/100g/min at rest and increased by exercise (8.0 ± 3.0 ml/100g/min, p < 0.001) and adenosine infusion (10.5 ± 4.9 ml/100g/min, p = 0.001), but not by breathing of moderate systemic hypoxic air at rest (1.5 ± 0.4 ml/100g/min, p = 0.16). Adipose blood flow was similar during exercise and adenosine infusion (p = 0.23), but vascular conductance was higher during adenosine. Finally, adipose blood flow during exercise in moderate systemic hypoxia was reduced (6.3 ± 2.2 ml/100g/min) compared to normoxic exercise (p = 0.004). In conclusion, the vasodilatation capacity of human subcutaneous adipose blood flow appears to be comparable at least to that induced by moderate intensity exercise. In addition, reduced blood flow in adipose tissue during systemic hypoxia is likely a result of sympathetic nervous activation that works to redistribute blood flow to exercising muscle in a condition of reduced oxygen availability.