Exercise increases methionine metabolism, which also increases its amino acid metabolic intermediate, homocysteine (Hcy). High Hcy levels increase cardiovascular disease (CVD) risk, whereas B-vitamins (folate, vitamins B6, and B12) can reduce Hcy. Research exploring the relationship between exercise and Hcy is equivocal.
Purpose: To determine whether plasma Hcy values, independent of plasma B-vitamin concentrations, are higher in active (HighPA; >420 min·wk−1) than less active (LowPA; ≤420 min·wk−1) males (M = 38) and females (F = 38).
Methods: Subjects were healthy, young (26 ± 5 yr), used no B-vitamin supplements in last 30 d, and reported being physically active for the last 5 yr. Physical activity (PA) groups were based on moderate- to high-intensity PA (min·wk−1) using 7-d PA records. Dietary intakes of B-vitamins were assessed using 7-d weighed food records. The differences of Hcy between PA and gender were examined using ANCOVA, with plasma B-vitamins as covariates.
Results: Mean PA was 220 min·wk−1 for LowPA (n = 36; V˙O2max = 42.8 ± 8.8 mL·kg−1·min−1) and 652 min·wk−1 for HighPA (n = 40; V˙O2max = 54.2 ± 9.7 mL·kg−1·min−1). Hcy (μmol·L−1) was not different between PA levels (LowPA = 7.5 ± 1.6; HighPA = 7.7 ± 1.6, P = 0.36) or sex (M = 7.8 ± 1.7; F = 7.4 ± 1.1; P = 0.13). Plasma folate was the only significant covariate (P<0.001). However, secondary analysis revealed that Hcy levels were significantly higher in the most active and fit (ExHighPA; range = 758-1085 min·wk−1; n = 11; >90% V˙O2max) compared with the sedentary ones (ExLowPA; range = 9-130 min·wk−1; n = 9; <70% V˙O2max; 8.6 ± 1.8 vs 6.7 ± 1.5 μmol·L−1; P = 0.007, respectively).
Conclusion: Hcy, independent of plasma B-vitamin levels, was not different between PA levels in nonsupplementing young adults, unless PA was high (>758 min·wk−1).
Department of Nutrition and Exercise Sciences, Oregon State University, Corvallis, OR
Address for correspondence: Lanae M. Joubert, Ph.D., Department of Nutrition and Exercise Sciences, Oregon State University, 103 Milam Hall Corvallis, OR 97331; E-mail: email@example.com.
Submitted for publication October 2007.
Accepted for publication May 2008.