You hear it everywhere. Exercise more. It's good for you. But why is it good for you? If you're not in any sports competitions, and you don't even like sports, what's the point?
I'm going to skip the parts about heart health, bone density, and that other stuff. In my mind, the single most important purpose of exercise is to clean out your body's sewer system.
Ever hear of lymph nodes? They exist in your neck, under your arms, and numerous other places all over your body. They're part of the lymph system,which carries oxygen from the blood into your cells, and carries away the cell's waste. The waste travels along the lymph vessels (like blood vessels, but for lymph fluid) and eventually gets filtered out by the lymph nodes.
Your blood is pumped around the circulatory system by the heart. The lymph system has no organ responsible for pumping the fluid around. It relies on one-way valves, the squeezing of the muscles around it, and certain other body movements. This means if you spend all day binge-watching your favorite Netflix show, your lymph system experiences hardly any movement at all.
Imagine your toilet backing up. Gross, right? When the cellular waste is not dumped, it sits around your body stinking up the place and causing trouble. This also means your cells aren't being well oxygenated. Such an environment encourages the growth of tumors because the immune system isn't able to properly dump all the garbage.
The immune system is responsible for clearing out malfunctioning cells, so when it can't do that, these malfunctioning cells get to hang around and multiply and basically go crazy. That's how cancer develops.
See why exercise is so important? Move your body! Keep your sewer system clean. You'll live longer.