Use of the Karvonen formula for a 20-year-old man (average shape; resting heart rate = 70 bpm). bpm, beats per minute; HRR, heart-rate reserve; MHR, maximum heart rate; RHR, resting heart rate. Source: Cardiorespiratory Training, Exercise Physiology Citation: Porcari JP, Bryant CX, Comana F. Exercise Physiology; 2015 Available at: http://fadavispt.mhmedical.com/DownloadImage.aspx?image=/data/books/2182/exercphys_ch15_f005-1.png&sec=165658050&BookID=2182&ChapterSecID=165657979&imagename= Accessed: November 06, 2017 Copyright © 2017 McGraw-Hill Education. All rights reserved