Plasma nitrite response in older women to a physical function test

Abstract

Background and aims: Nitric oxide (NO) may play a critical role in facilitating the delivery of blood to active skeletal muscle, ultimately impacting functional health in older adults. Plasma nitrite is a useful marker of vascular NO bioavailability. The aim of the current investigation was to examine the effect of a widely used physical function test on plasma nitrite concentrations in older adults.

Methods: Venous blood was drawn before, immediately following, and 10 minutes following the completion of a 400-m walk test. Blood samples were added to heparin and frozen for subsequent analysis of nitrite levels using chemiluminescence.

Results: Twenty six (79±4 yrs) women participated in this study. Plasma nitrite levels decreased approximately 22% from baseline following a 400-m walk. Percent change in plasma nitrite was related to walking speed (r=-0.550, p=0.004).

Conclusions: These data suggest an alteration in plasma nitrite concentration following a functional test which may impact functional health.

Fig. 1

The time course for change in plasma nitrite; prior to (129±16 nM), immediately following (102±13 nM) and 10 minutes following (100±12 nM) the 400-m walk. Data presented as mean±SEM.

Fig. 2

Individual changes in plasma nitrite following a 400-m walk.

Fig. 3

The relationship between change in plasma nitrite concentration following the 400-m walk and walking speed (r=−0.550, p=0.004).