If you’ve just started a new training program and are wondering what an MHR is, you’re not alone. Fitness gurus love jargon, which can cause plenty of confusion among athletes.

MHR, or “maximum heart rate,” is a tool used to calculate different target heart rates for a zone-based training program. There are multiple ways to calculate an MHR, but most of them use a simple age-based formula.

To help you better understand what a maximum heart rate is, we’ve put together this guide to all the ins and outs of HR zones. Here’s what you need to know.

Maximum Heart Rate Definition

Your maximum heart rate is simply a tool that you can use to determine your different heart rate zones for specific training programs. Once you know what your maximum heart rate is, you can then figure out how much effort you should put into a given exercise for your training goals.

How To Calculate Your Maximum Heart Rate

There are quite a few different ways to calculate your maximum heart rate. However, unless you have access to high-end laboratory equipment, it’s essential to keep in mind that most HMR calculations are an educated guess.

For those of us at home that don’t happen to have multi-million dollar machines, the most common way to estimate your MHR is through the “Astrand Method,” also known as the age-based method.

The standard formula for MHR using your age is the following:

  • MHR = 220 – Age

This formula has been around for years, and it’s still widely used in the fitness world. However, a 2007 study from Oakland University suggested a new, perhaps more accurate way to estimate one’s MHR:

  • MHR = 207 – (Age x 0.7)

According to the study, this new model is much more precise; however, for most people, it provides an MHR that’s just 2-8 bpm off from what you’d get from using the standard formula.

If you want more precision in your MHR calculation, the second formula is your best bet. Otherwise, the standard formula provides a quick and easy way to estimate your MHR.

What’s The Difference Between THR And MHR?

A THR, or a target heart rate, is the range that your heart rate should be in during a given exercise. Your THR is expressed as a percentage of your MHR, and it is an important thing to know when following a heart rate zone-based training program.

How To Use MHR For Training

So, in some exercise programs, you might be asked to run at an exertion level of about 50%. If you’re 50 years old and your MHR is 170, your 50% THR would be 85 beats per minute. Alternatively, for the same 50-year-old athlete, a 75% THR would be about 128 beats per minute.

Here’s a sample zone training table for different target heart rates for a 25-year-old athlete:

Zone Target HR
30% 59
35% 69
40% 78
45% 88
50% 98
55% 108
60% 117
65% 127
70% 137
75% 147
80% 156
85% 166
90% 176
95% 185
100% 195

To determine your own personal THR zones, use the following formula:

  • THR = MHR x Target Zone %

Then, when following a training plan that tells you to bike at 75% of your MHR, you need to pace yourself so that your heart rate stays around this level. Alternatively, some training programs will outline specific heart rate “zones” that you should aim to achieve different fitness outcomes. These include the following:

Healthy THR Zone: 50-60% MHR

Your “healthy” THR zone is usually quite a comfortable zone to exercise in and is normally used for light to moderate exercise. Most people should be able to have a full conversation in this zone.

However, exercise at this level doesn’t provide much in the way of cardiovascular performance benefits. That being said, studies show that even light exercise at this level can help reduce body fat, cholesterol levels, and blood pressure.

 Fitness THR Zone: 60-70% MHR

In the fitness THR zone, most people will breathe heavily, but should still be able to say short sentences. This zone provides slightly more intense exercise and generally involves brisk walking or something similar. Like the healthy THR zone, the fitness THR zone can help burn calories.

Aerobic THR Zone: 70-80% MHR

The anaerobic THR zone is commonly reached during vigorous exercises, such as running or cycling, and often limits speaking to just short phrases. This is the ideal zone to be in for endurance training as it helps to improve circulation and lung capacity. In general, the body burns equal amounts of fat and carbohydrates in this zone.

Anaerobic THR Zone: 80-90% MHR

Interval training workouts and similar high-intensity exercises often bring athletes to the anaerobic THR zone or “anaerobic threshold.” At this stage, you generally can’t speak beyond a single word because your body is working too hard.

Training at the Anaerobic THR zone helps improve one’s VO2 maximum. It is crucial for building up overall speed and power, so you’ll often see sprinters training at this level to improve their performance.

Red Line THR Zone: 90-100% MHR

The red line THR zone is generally reserved for just short bursts of effort during interval training to build power. Anyone looking to train at this level should consult their doctor, particularly if they have a history of heart problems or high blood pressure.

Proceed With Caution

If you’re new to exercising, it’s important to note that your THR zones are just a guide. Listening to your body is the essential thing. If you’re not sure that you’re exercising at the right THR or what your MHR should be, consult your doctor.

Frequently Asked Questions About Maximum Heart Rates

Here are our answers to some of your most commonly asked questions about MHRs:

Is it bad to exercise at your maximum heart rate?

Most people will not be able to exercise at their MHR for more than a minute at a time. In reality, unless you’re a professional athlete, you’re unlikely to train above your anaerobic threshold for any considerable period.

While exercising intermittently at your MHR isn’t necessarily “bad” for you if you’re otherwise healthy, one study from Dalhousie University did find that recreational hockey players who frequently exceeded their MHR took longer to recover after exercise.

So, if you do want to train above your MHR, it’s best to consult your doctor first.

What happens if you go above your maximum heart rate?

For people who are otherwise healthy and don’t have coronary artery disease (nor any of the major risk factors of a heart attack), going above one’s MHR is not inherently dangerous. However, it can increase your risk of injury and overtraining, especially if done regularly.

How long should you stay at your maximum heart rate?

The question of how long you “should” stay at your maximum heart rate is really more one of how long you “can.” Most people would not be able to sustain the effort necessary to stay at their MHR for more than a minute or so. Thus, even if you tried to stay above your MHR for a long time, you’re unlikely to do so.

Can your heart rate go above 220?

One’s heart rate can technically go above 220, but this isn’t as simple as it sounds. Most humans would have a hard time getting their HR above 200, even with strenuous exercise.

That being said, there have been rare instances where someone’s heart rate has well exceeded this 220 bpm threshold. A cool 2012 study from the University of Massachusets did document a case where an individual’s heart rate was around 600 bpm.

They also referenced a few other studies where patients had heart rates between 300 and 500 bpm that lasted upwards of two days. However, this is not normal nor likely for most people.

At what heart rate should you go to the hospital?

Most adults that are sitting down and resting will have a resting heart rate between 60-100bpm. MedStar Washington Hospital Center recommends that anyone experiencing a heart rate that’s consistently above 100bpm while sitting down should see a doctor for an evaluation.