What do you mean by that? It does or it does not?
Swimming because it uses all body strength! they actually use it for physical therapy too!
<span>Heart Rate Reserve, HRR. Heart rate reserve (HRR) is the difference between resting heart rate (HR<span>rest) and maximum heart rate</span> (HRmax). Heart rate reserve is used when determining exercise heart rates. The Karvonen formula is used to calculate exercise heart rate at a given percentage training intensity.</span>
D. Smallpox is your answer
