Breastfeeding parents often wonder if exercise impacts milk supply. For most, moderate physical activity does not decrease milk production. Research shows moderate exercise is compatible with breastfeeding and does not affect milk supply, its composition, or infant growth.
Understanding Milk Production and Exercise
Milk production operates primarily on a supply-and-demand principle: the more milk removed, the more the body produces. This process is largely regulated by hormones. Prolactin, a key hormone for milk synthesis, increases in response to a baby’s suckling or milk expression. After delivery, the drop in pregnancy hormones like estrogen and progesterone allows prolactin to become more active, initiating significant milk secretion.
Exercise generally does not inhibit milk production hormones. While physical activity requires energy, the body adapts to meet the dual demands of exercise and lactation. Breastfeeding itself expends 300 to 500 calories daily, comparable to moderate exercise. Exclusively breastfeeding women need an additional 400-500 kcal per day for milk production during the first six months. The body can draw upon fat stores accumulated during pregnancy to help cover some of these additional energy needs.
Key Considerations for Exercising While Breastfeeding
Adequate hydration is important for breastfeeding parents who exercise. Water is a primary component of breast milk, so sufficient fluid intake supports milk volume. Drink water before, during, and after workouts, aiming for at least 12-16 glasses daily.
Sufficient caloric intake is also important to support milk production and energy levels. Most breastfeeding parents need 2,300 to 2,800 calories daily, depending on activity level. Rapid weight loss, defined as more than 0.5 kg (1 lb) per week, can signal insufficient calorie intake, which might affect milk supply.
Wear supportive, comfortable clothing, especially a well-fitting nursing sports bra, for comfort during exercise. Breastfeeding before a workout can also reduce breast fullness. Listen to your body, gradually increasing intensity and duration while monitoring for discomfort or fatigue.
Addressing Common Concerns
A common concern involves lactic acid buildup during exercise and its perceived effect on milk taste or infant acceptance. While intense exercise can temporarily increase lactic acid levels in breast milk, moderate activity typically does not. Even if elevated, levels usually return to normal quickly, and there is no evidence this harms the baby. Some infants might show temporary fussiness, often due to sweat’s saltiness rather than taste.
It is common to confuse a perceived decrease in milk supply with an actual physiological reduction. After exercise, some parents might express less milk due to temporary dehydration or changes in blood flow, not a true drop in production. Consistent milk removal through frequent nursing or pumping remains the primary driver of milk supply. Regular, moderate exercise is safe and beneficial for overall well-being, contributing to physical fitness, mood improvement, and reduced stress. Exercise may even increase beneficial hormones in breast milk, such as adiponectin, which could influence infant metabolism.