Maximum Heart Rate.
Maximum heart rate (HRmax or MHR) is the highest heart rate a person can achieve with physical stress while staying within safe limits – that is without causing harm to the heart. It varies significantly from person to person and depends on age. Even within one athlete team in their 20’s, MHR can vary from 160 to 220.
How to Calculate Maximum Heart Rate.
Maximum heart rate can be most accurately determined using the cardiac stress test. In this test, the person is put through a physical exercise and at the same time, his heart is monitored by an ECG (electrocardiogram). More commonly a treadmill is used for this purpose. The exertion of the person is gradually increased by increasing the speed or slope of the treadmill.
This is continued until some changes in ECG denote changes in heart function. The treadmill is then stopped. The duration of such a test can be ten to twenty minutes and is advised only under medical supervision. The ECG consists of a P wave, QRS complex and a T wave ( and sometimes a U wave is seen in 50% to 75% of the cases). The interval in seconds, millimeters and large squares between two successive R waves is used to calculate the heart rate achieved via the stress test.
The ECG helps to calculate the heart rate (HR) as follows:
- HR = 1500/RR interval in millimeters.
- HR = 60/RR interval in seconds.
- HR = 300/ number of large squares between two successive R waves.
Al these cases indicate the heart rate at that instant given that subsequent RR intervals are constant.
Generally, people use certain formulae which help to predict your maximum heart rate.
Formulae to Predict Maximum Heart Rate.
Maximum heart rate (MHR) can be predicted or estimated using the following formulae. However variations in the result using the formula and the actual MHR were up to 20 beats per minute in 95% of the individuals of a given age.
1)MHR = 220 minus your age.
It has accepted since long that the maximun heart rate starts out at 220 bpm and falls by one beat every year. So if your age is 45 years, your predicted MHR will be 220 – 45 = 175.
This formula is commonly used because it is simple and easy to calculate the MHR with it. However it does not carry weight with the sports health professionals. This is because it was not developed from research but from data of certain references. Subsequent studies have indicated its inaccuracy. It is a traditionally male based calculation and gives an overestimated result for women.
2) Maximum Heart Rate for women = 206 minus (0.88 x age).
This formula was proposed by Dr Martha Gulati et al in 2010 for women athletes, after investigating the association between heart rate, exercise and age in more than 5000 women.
3) MHR = 206.3 minus (0.711 x age).
Londeree and Moeshberger from the University of Missourie in Columbia suggested another formula in 1982, which is shown above. They indicated that MHR varies with age but not in a linear fashion.
4) MHR = 217 minus (0.85 x age)
This formula was proposed by Miller et al in 1993.
5) MHR = 206. 9 minus (0.67 x age).
USA researchers Jackson et al in 2007 revealed this formula and claimed it to depict a more accurate connection between age and maximum heart rate.
6) White et al, UK researchers, introduced the following formula in 2008 with variation for men and women endurance and anaerobically trained athletes.
- For Male Athletes:- MHR = 202 minus (0.55 x age).
- For Female Athletes:- MHR = 216 minus (1.09 x age).
7) Combination of Miller, Londeree and Moeshberger.
MHR can be predicted using the combination of the Miller formula with the research done by Londeree and Moeshberger.
With the Miller formula calculate MHR, using the formula MHR = 217 – (0.85 × age).
- Reduce 3 beats for elite athletes under 30 years of age.
- Add 2 beats for 50 year old elite athletes
- Add 4 beats for 55+ year old elite athletes
- Use this MHR value for running training athletes
- Subtract 3 beats for rowing training athletes
- Subtract 5 beats for bicycle training athletes
There are more than 40 formulae proposed to predict maximum heart rate, like the ones mentioned above. The least objected of formula is the following.
Max. HR = 205.8 minus (0.685 x age).
Max Heart Rate Calculator.
You could use the heart rate calculator which will give you your MHR instantaneously. It is available here.
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