Bodybuilding.com - How To Calculate Your Heart Rate!

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Did you know?
When doing cardio to burn fat, you want to stay in the range of 65%-70%!

This new formula should apply to all healthy men and women between 18 to 81 years of age. The old formula has a 8 % difference than the new and improved one! Learn why!

By: Matt Danielsson

When you're doing cardio to burn fat, you want to stay in the range of 65%-70% of your maximum heart rate. If the goal is to increase stamina and aerobic capacity, you aim for 85%. Piece of cake, everyone knows that. But how do you determine your maximum heart rate? For decades, the formula has been pretty simple: 220 minus your age = max heart rate.

However, there are some wrinkles to that formula when you consider guys like president Bush. At 55 years of age should have 220 - 55 = 165 as his maximum heart rate. Problem is, the guy is closer to a heart rate of 180 when doing his annual, widely published checkups. How can this be? And if Bush's real max heart rate is about 8% off from the standard formula, doesn't that mean that your so-called 70% or 85% could be equally skewed?

Harvard's Men's Health Watch published an explanation last year that sheds some new light on this matter. A couple of Colorado scientists did some exercise test reality checking and reviewed the results of 18,712 men and women of all ages. Based on the this real-life data they came up with a new formula:

Maximum heart rate

This should apply to all healthy men and women between 18 to 81 years of age. Now, president Bush is in exceptionally good health for his age and still exceeds his predicted maximum. Nonetheless, it appears the new formula is more accurate.

Simple Target Heart Rate Calculator
Using the 208 - (0.7 x age in years) formula.

The Karvonnen formula is more advanced since it also takes into account your resting heart rate. This is your heart rate at complete rest. To determine this, take your pulse for 60 seconds just before you get out of bed... or take it for 30 seconds and multiply by 2.

Advanced Target Heart Rate Calculator
Using the Karvonen Formula.

For your age, use a whole year. (Between 0 and 100)
Put your Resting Heart Rate in the next box. (Between 30 and 100)
In the % box, use a number between 50 and 85. Do not include the %.
Click on the Calculate button, and it will calculate your target heart rate or that percentage.

So, in practicality, what does this mean? The difference is the greatest for young and elderly people; people in the mid-forties will get the same numbers as with the old formula. However, if you're 20, your max heart rate is 194 instead of 200, meaning 70% of max = 136 instead of 140 and 85% of max = 165 instead of 170. That makes a difference when you're setting up the treadmill next time you're doing cardio. For a 65-year old, the max heart rate is 163 instead of 153, with 70% of max = 114 instead of 107 and 85% of max = 139 instead of 130.

Age	Old Max	New Max	70%	85%
20	200	194	136	165
25	195	191	134	162
30	190	187	131	159
35	185	184	129	156
40	180	180	129	156
45	175	177	124	150
50	170	173	121	147
55	165	170	119	145
60	160	166	116	141
65	155	163	114	139
70	150	159	111	135