Had an echo-stress test.i'm 54woman.was told i had to reach target ht rate of 142.is it correct?per my calculation,210-54 is 156. 85% of 156 is 132.6.

Statistical error: That formula is for the entire population and underestimates older people. Adjust for age and 85% of your max HR is 145. The third formula in the graphic is usually used for women (yours is 135) and a formula for women over 40 with mean of 55 (you're 54) puts 85% of your max HR at 131. At a sustained HR above 125 your heart was sufficiently stressed for the test which is reliable in 4 out of 5.