If your answer is ‘because we sweat’ then think again.
The body as a complete system of detoxification all on it’s own. When you breathe, your lungs detoxify the air for you. The lymph nodes flow through the blood and soak up toxins in our system. Not to mention the heroic liver and it’s detoxification process, and of course the kidneys…
What exercise does is rev up these processes, so that they work harder and faster for a period of time. A good analogy is a toilet flush, the stronger the mechanism, the more effective the flush.
Which reminds us to drink more water during exercise to help move the detox along even more, so the skin can sweat and the kidneys can effectively filter toxins. More water plus an increased heart and breathing rate means your body is flushing, flushing, gone. What’s not to love !