The Impact of Acute Exercise in the Heat on Breast Milk Production and Composition in Lactating Women

Launched by PROVIDENCE COLLEGE · Jun 16, 2025

Keywords

ClinConnect Summary

This clinical trial is studying how exercising in hot conditions might affect breast milk production and its nutritional content in women who are currently breastfeeding. Researchers want to find out if heat makes a difference in the amount of milk produced over a 24-hour period and whether the energy and nutrients in the milk change after a 60-minute exercise session in a hot environment compared to a comfortable, cooler temperature.

Women between 18 and 45 years old who are breastfeeding babies between 6 weeks and 24 months old may be eligible to join, as long as they had a full-term single baby without pregnancy complications and don’t have certain health issues like diabetes or recent heat illness. Participants will visit the study site four times, including one visit for initial testing and two separate exercise sessions—one in a hot room and one in a cooler room. During these sessions, they will walk on a treadmill for an hour while researchers monitor heart rate, body temperature, and fluid loss. Breast milk will be collected right after exercise and 24 hours later, and mothers will track how much milk their baby consumes over a full day using a scale. This study helps us understand how heat and exercise might impact breastfeeding, which could be important for mothers who are active or live in hot climates.

Gender

FEMALE

Eligibility criteria

• Inclusion Criteria:
• • Currently breastfeeding or pumping expressed breastmilk for their 6-week to 24-month infants
• • Aged 18-45 years old
• • Delivered their infants between 37-42 weeks of gestational age
• Exclusion Criteria:
• • Obsterical complications during pregnancy
• • multiple gestation
• • Chronic disease (i.e., diabetes, hypertension, metabolic disease)
• • Heat illnness in the last 3 month