Important to get the maximum heart rate right

Maximum heart rate (HRmax) is an important tool to uncover cardiovascular disease. During stress testing, age-expected maximum heart rate is used as a guideline for when the test should be concluded. If the test is finished before the load is high enough, you risk not to detect subclinical heart disease. Therefore, it is of great clinical relevance to have a way to accurately estimate HRmax.

The traditional formula for determining HRmax is "220 minus age", but can underestimate HRmax by up to 40 beats per minute in seniors. In fact, the method is inaccurate already at an age of 30–40 years, and gets more inaccurate the older you are.

In The HUNT Fitness Study, we measured accurate maximum heart rate in 3,320 healthy adults aged between 19 and 89. Based on these tests we made a completely new formula which estimates maximum heart rate far more accurately than "220 minus age". The HRmax Calculator is based on this formula: "211 - 0.64*age".

Read the full article:
Age-predicted maximal heart rate in healthy subjects: The HUNT Fitness Study

Maximum heart rate and beta blockers

Our HRmax Calculator asks you to check a box if you use beta blockers. The reason for that is that heart patients and others on beta blockers will have a reduced maximum heart rate.

Beta blockers bind to adrenaline receptors and block access for adrenaline molecules. Adrenaline causes the heart to pump both harder and faster. Hence, beta blockers reduce the maximum heart rate. The magnitude of the reduction depends on the dosage, so we recommend that you test yourself to find an exact HRmax.

Find your exact maximum heart rate

Our research shows that the variation in maximum heart rate within age groups is fairly large. Genetics contribute more to maximum heart rate than physical fitness. Therefore, it's hard to make a calculator that can estimate maximum heart rate precisely, and we recommend all of you who want to find your real HRmax to test yourself by pushing yourself to exhaustion:

1. Warm up thoroughly so you start sweating.
2. Do two intervals, each four minutes long. During the intervals you should be too short of breath to talk. Intersperse each interval with three minutes of active rest.
3. Start the third interval, but two minutes in, increase your speed even further an run until you're too exhausted to continue. Your HRmax will be the highest heart rate you reach. The heart will reach a plateau at which it cannot beat any faster, regardless of how much you increase the workload.

If you don't have a heart rate monitor, you can measure the maximum heart rate by holding two fingers to your neck for 30 seconds right after finishing the test. Double the number you get to find your HRmax.

Maximum heart rate and exercise

During 4x4 interval training, you use your maximum heart rate to give the heart good exercise. Our HRmax Calculator calculates at which heart rate you should exercise when performing this kind of interval training. The 4x4 principle can be used in a variety of activites, including running, biking, swimming and rowing.

1. Start with a ten minute warm-up at approximately 60 % of HRmax to get you sweating.
2. Do four intervals, each four minutes long. The last two minutes of each interval your heart rate should be at 90–95 % of HRmax, so you become short of breath. Use the first two minutes of each interval to reach this heart rate level.
3. Between each interval, your should perform active resting at a heart rate of approximately 70 % of HRmax. This is the zone where the body clears lactic acid most efficiently.
4. End with a ten minute cool-down with lighter activity after the last interval.

Watch our video for further explanation on how to perform effective 4x4 interval training: