Plasma ADMA concentrations associate with aerobic fitness in postmenopausal women

Aims: Asymmetric dimethylarginine (ADMA) is an endogenous competitive inhibitor of nitric oxide (NO) synthase, an enzyme responsible for the generation of NO. Plasma concentrations of ADMA increase in the elderly and in postmenopausal women. In fact, an elevated ADMA level is a risk factor of cardiovascular disease. Aerobic exercise has a beneficial effect on cardiovascular disease. However, the relationship between ADMA and aerobic fitness is unknown. The aim of this study was to determine whether plasma ADMA concentrations correlate with aerobic fitness levels in postmenopausal women.

Main methods: Thirty healthy postmenopausal women aged 50-76 years participated in this study. We measured plasma concentrations of ADMA and oxygen consumption at the ventilatory threshold (VO2VT) as an index of aerobic fitness. Subjects were divided into the low aerobic fitness (Low fitness) and high aerobic fitness (High fitness) groups, and the dividing line was set at the median VO2VT value.

Key findings: VO2VT was significantly higher in the High fitness group than in the Low fitness group (P<0.01). The plasma ADMA concentrations in the High fitness group were significantly lower than those in the Low fitness group (P<0.05). There was a negative correlation between plasma ADMA concentrations and VO2VT (r=-0.532, P<0.01).

Significance: We found that plasma ADMA concentrations were associated with aerobic fitness in postmenopausal women. The results of this study suggest that habitual aerobic exercise may decrease plasma ADMA concentrations.