High-intensity exercise increases breast milk adiponectin concentrations: a randomised cross-over study

Adiponectin plays a role in glucose and fat metabolism and is present in breast milk. Circulating adiponectin increases acutely after endurance exercise. The purpose of this randomised, cross-over study was to determine the acute effects of exercise on adiponectin concentrations in human breast milk. Participants (N = 20) completed three conditions in the lab: 1) Moderate-intensity continuous training (MICT), 2) High-intensity interval training (HIIT), and 3) No activity (REST). At each condition, we collected breastmilk at 07:00 hours (before exercise/rest), 11:00 hours (immediately after exercise/rest), 12:00 hours (1 hour after exercise/rest), and 15:00 (4 hours after exercise/rest) and determined adiponectin concentrations using enzyme-linked immunosorbent assay. We compared changes in adiponectin concentrations after MICT and HIIT, adjusted for the morning concentration on each test day, with those after REST, using paired t-tests. Adiponectin concentrations increased 1 hour after HIIT, from 4.6 (± 2.2) μg/mL in the 07:00 hours sample to 5.6 (± 2.6) μg/mL. This change was 0.9 μg/mL (95% confidence interval 0.3 to 1.5) greater than the change between these two timepoints in the REST condition ( p = .025). There were no other statistically significant changes in adiponectin concentrations. HIIT may increase adiponectin concentrations in breast milk acutely after exercise.