To increase their muscle mass and strength. The main anabolic steroid hormone produced by your body is testosterone. Testosterone has two main effects on your body: Anabolic effects promote muscle building.
Your heart rate is -high- or it is beating faster, meaning it’s working more and pumping more blood.
Health insurance offers a way to reduce such costs to more reasonable, affordable amounts. The way it typically works is that the consumer pays an up front premium to a health insurance company and that payment allows you to share "risk" with lots of other people who are making similar payments.
You should wear tight compression outfits to decrease the possibility of drag, especially in an olympic race. You could even wear a swim hat to lower drag from your hair.