Medical Q&As

Breastfeeding - exercise safe for baby?

My baby is now almost ten months old and is still breastfed. I desperately want to get back into a regular exercise program. Can you tell me if there's any truth in the following rumour I've heard: I've been told that toxins released from the fat cells in your body during exercise, can get into the breast milk, and as a result you shouldn't exercise while breastfeeding?

The rumour you mention is based on the suggestion that breast milk after exercise contains increased amounts of lactic acid, which might be harmful to the baby. This suggestion has been studied scientifically and refuted in the medical literature. One study focussed on breast-feeding mothers and divided the group into three cohorts. One group was put on a weight reduction diet, the second was placed on an exercise and diet programme and the third group acted as controls for the study. The study concluded that the volume and composition of the breast milk did not differ significantly between the three groups and that the infant weight did not differ. Looking at this issue on a purely hypothetical basis it is conceivable that a higher level of lactic acid in the milk might possibly alter the taste of the milk but there is no evidence that this could be harmful. It is perfectly safe for you to resume a regular exercise programme without fearing that it might be harmful to your baby. Such a programme will restore your level of physical fitness and help to restore your weight and figure to normal. A fitter healthier mother is a very good outcome for your baby. You can safely ignore the rumour.