How your muscles work: The energy systems used during exercise

Thursday, February 11, 2016. Author Dr Pleuni Hooijman

Energy Systems

During your workout you’re gasping for air, and afterwards all you can think about is refuelling on carbs and fats. These two seemingly distinct elementary needs are more intertwined than you might expect.  It is all about producing ATP (adenosine triphosphate) - the only compound which provides energy to your cells.

When exercising, your muscles consume huge amounts of energy to keep them contracting and relaxing.  We know that our food provides us with energy, but the sugars and fats from the muesli bar you just ate are not used immediately by your working muscle fibers.  Via long and complex pathways the energy sources from our food and the body’s reserves are processed into substrates (small molecules which enzymes can act on) that help generate the only true ‘energy’ currency for cellular processes: ATP.  It is ATP that energizes our bodily processes, from cell development to explosive muscle contractions.  The largest volume of ATP is produced in the presence of oxygen, which is why our breathing rate increases dramatically when we exercise.

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