Exercise releases a signalling molecule into the bloodstream that boosts metabolism, improves heart health, and regulates weight, scientists have discovered.
The “lipokine” is released by brown fat – the “good” type of fat that generates heat rather than stores calories.
US researchers conducted blood tests on 56 study participants, split into two groups, who were put through sessions of moderate-intensity exercise.
One group rode a stationary bike for 40 minutes while the other ran on a treadmill for 45 minutes.
“One lipokine just shot right up to the top,” said researcher Dr Kristin Stanford, from Ohio State University.
The lipokine was identified as a molecule called 12,13-diHOME that had previously been linked to exposure to cold temperatures.
Other studies have not shown that exercise causes brown fat to burn up more calories.
Instead, when exercising, the lipokine signalling molecule released by brown fat helps muscles to work more efficiently, the scientists believe.
“It’s fascinating that rather than burning calories during exercise – which is what occurs with cold exposure – brown fat is functioning to signal the muscles to take up more fatty acids to use as fuel,” said Dr Stanford.
“During exercise, all the different metabolic tissues, surprisingly including fat tissues, ‘talk’ to each other, which enables the muscles to use energy, contract and perform.”
The discovery was confirmed by studying mice, which also showed increased levels of the lipokine in their blood during exercise.
After surgical removal of brown fat stores from the mice, levels of the molecule were no longer boosted by exercise.
The research appears in the journal Cell Metabolism.
