<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>
Answer:
sexual reproduction , I think
Answer:
If you are caught between a rock and a hard place, you are in a difficult situation where you have to choose between two equally unpleasant courses of action.
