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Switching the Wall
14 June 2017

Switching the Wall

Have you ever been exercising and suddenly felt as if you can’t carry on? This phenomenon known as ‘hitting the wall’ occurs when our muscles can no longer use the usual supply of glucose for their energy source. It’s known that endurance training causes muscles to switch to ‘burning’ fat rather than glucose, but new research shows that this change is stimulated by and is also dependent on a molecule called PPARδ. Pictured are types of muscle fibres that use glucose differently, stained blue, green and red. Using a drug to activate PPARδ in the muscles of inactive mice, researchers found that there was an increase in fat being used as an energy source and that inactive mice were able to exercise for longer, without the need for training. This insight could be used to help people unable to exercise because of health problems.

Written by Katie Panteli

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BPoD stands for Biomedical Picture of the Day. Managed by the MRC Laboratory of Medical Sciences until Jul 2023, it is now run independently by a dedicated team of scientists and writers. The website aims to engage everyone, young and old, in the wonders of biology, and its influence on medicine. The ever-growing archive of more than 4000 research images documents over a decade of progress. Explore the collection and see what you discover. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.

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