Endothelial Nitric Oxide Synthase (NOS3) +894 G>T Associates with Physical Activity and Muscle Performance among Young Adults

Objective . We examined the influence of missense polymorphism, endothelial nitric oxide synthase ( NOS3 ) +894 G>T (rs1799983), on habitual physical activity (PA) and the muscle strength response to resistance training (RT). Methods . Men ( n = 354 ) and women ( n = 424 ; 24.3 ± 8.0  yr) were genotyped. Subjects reported hr/wk in vigorous and light intensity PA and sitting on the Paffenbarger PA questionnaire. One repetition maximum assessed muscle strength. Multivariable and repeated measures ANCOVA tested differences among NOS3 +894 G>T and PA and RT phenotypes by gender. Results . hr/wk in vigorous intensity PA ( 5.4 ± 1.2 versus 8.3 ± 0.4 ; P = 0.019 ), more hr/wk in light intensity PA ( 42.1 ± 2.4 versus 35.8 ± 0.7 ; P = 0.011 ), and less hr/wk sitting ( 37.6 ± 2.8 versus 45.8 ± 0.9 ; P = 0.006 ) than those with the G allele. Women with NOS3 +894 TT gained more absolute ( 4.4 ± 0.3 versus 3.7 ± 0.8  kg; P = 0.013 ) and relative ( 78.3 ± 5.8 versus 61.9 ± 1.8 %; P = 0.007 ) strength than those with the G allele. Conclusions . NOS3 +894 G>T associated with PA among men and women and the muscle strength response to RT among women only. Our findings indicate the need for prospective studies examining the influence of NOS3 variants on PA and the muscle response to RT as well as elucidating underlying mechanistic pathways for the associations observed.