Abstract
The purpose of this study was to observe the influence of the fullness of breast milk
in the breasts prior to exercise on the concentration of lactic acid in breast milk
following exercise. Twenty-three lactating women were randomly assigned to Group E
(n = 11), which nursed and/or collected as much of the breast milk as possible prior
to maximal exercise, and Group F (n = 12), which did not nurse or collect milk at
least two hours prior to maximal exercise. Milk was collected at rest preexercise
and 10, 30, 60 and 90 minutes postexercise and was analyzed for concentrations of
lactic acid. ANOVA demonstrated 1) a significant increase in lactic acid in the milk
at all postexercise collections for both groups and 2) a significant group vs postexercise
time interaction for lactic acid concentration in milk. These differences represented
differences in 1) time to peak lactic acid concentrations in milk (Group F = 10 min;
Group E = 30 min) and 2) time for postexercise decreases in lactic acid concentrations
in milk. Thus, the state of fullness of milk in the breasts is a factor which affects
the concentration of lactic acid in breast milk following maximal exercise.
Key words
Lactic acid and breast milk - exercise in lactation
