Your muscle cells and other cells need energy. One source of that energy is a molecule called ATP. You can think of each ATP molecule as an extremely tiny battery. When the energy in an ATP molecule is used, such as for causing a muscle to contract, the ATP is changed into a molecule called ADP, which you can think of as a battery that’s been drained.
Inside many of your cells are charging stations where energy is put into ADP to change it back to ATP. [1] Those charging stations are microscopically small structures called mitochondria (singular mitochondrion).
Why is this important to know? The more mitochondria there are in a cell, in a muscle, or in your body, and the better those mitochondria function, the more ADP can be changed into ATP, which means that more energy is available for all of the things you might need energy for. And you can influence the quantity and quality of your mitochondria through your nutrition and physical activity choices. [2]
[1] That energy has to come from somewhere, but that’s another story.
[2] How Exercise—Interval Training In Particular—Helps Your Mitochondria Stave Off Old Age, Science Daily
