Objective: To determine the extent to which brown adipose tissue (BAT) heat output is influenced by treadmill exercise.
Design: The aortic blood core and interscapular BAT temperatures were recorded continuously during a short bout of intense exercise (different for each rat stock) in a treadmill and the ensuing 1-h recovery, sampling blood flows at timed intervals.
Subjects: Conscious Wistar, Zucker lean and Zucker obese rats.
Measurements: Aortic and interscapular BAT temperatures and tissue blood flow.
Results: Basal mean temperatures were highest for Wistar. Exercise provoked increases in aortic core temperatures in all three groups, slowly cooling off during recovery. Exercise and/or fatigue induced increases (vs aortic core temperature) of IBAT temperature. The effects were less marked in obese rats.
Conclusion: Increases in BAT temperatures induced by exercise were counteracted by parallel decreases in blood flow, resulting in insignificant losses of heat from intarscapular BAT during exercise and recovery both in lean and obese rats.