By GINA KOLATA for NYTIMES
Donald Kirkendall, an exercise physiologist at the University of North Carolina, will never forget the time he put a heart-rate monitor on a member of the United States rowing team and asked the man to row as hard as he could for six minutes.
The standard formula for calculating how fast a human heart can beat calls for subtracting the person’s age from 220. The rower was in his mid-20’s.
Just getting the heart to its actual maximum rate is an immense effort and holding it there for even a minute is so painful that it is all but inconceivable for anyone who is not supremely motivated, Dr. Kirkendall said. But this rower confounded the predictions…..