To investigate the link between serum vaspin levels and physical activity and/or physical fitness in Japanese.

A total of 156 subjects (81 men and 75 women) was enrolled in this cross-sectional study. Serum vaspin levels, physical activity by uniaxial accelerometers, peak oxygen uptake, and metabolic risk parameters were evaluated. We also assessed anthropometric and body composition parameters.

Serum vaspin levels were over the level of 10 ng/mL in 15 subjects (9.6 %: Vaspin High group). In Vaspin Low group (<5 ng/mL: 74 men and 67 women), serum vaspin levels were 0.12 ± 0.18 ng/mL in men and 0.39 ± 0.70 ng/mL in women. Peak oxygen uptake was significantly and positively correlated with serum vaspin levels even after adjusting for age, physical activity evaluated by Σ[metabolic equivalents × h per week (METs⋅h/w)], BMI, and other confounding factors in men. In turn, physical activity was significantly and positively correlated with serum vaspin levels even after adjusting for confounding factors in women.

Serum vaspin levels were closely associated with physical fitness in men and physical activity in women independent of body composition in this Japanese cohort.