When heart rate is too high Going higher than your maximum heart rate for long periods of time could be dangerous for your health. That’s especially true if you’re new to exercise.

Vigorous: 77% to 95% of MHR This is the zone to aim for when training for endurance. It spurs your body to improve your circulatory system by building new blood vessels and increases your heart and lung capacity. Aiming for 20 to 60 minutes in this zone is believed to give the best fitness training benefits.

Aim to be at your THR for at least 15 to 20 minutes workout time, and ideally 35 to 45 minutes. If you’re a beginner, start at 65 percent to 70 percent of your maximum heart rate and gradually increase the intensity.

A typical one-hour session might include 10 minutes in the 50-60% zone warming up and cooling down, 30 minutes at a sustainable pace at 60-70%, 12 minutes pushing a little more at 70-80%, 6 minutes going hard at 80-90% and 2 minutes all-out at 90-100%.

Being aware of your heart rate during exercise means that you’ll look to targeted zones to reach your goal. In fact, weight loss and better fitness are easier to achieve with calculated results in mind. As a result of your efforts, your body responds by using oxygen more efficiently than before.

To determine your maximum heart rate, subtract your age from 220. For example, a 35-year-old woman’s maximum heart rate is 220 minus 35 — or 185 beats per minute. To enter the fat-burning zone, she’d want her heart rate to be 70 percent of 185, which is about 130 beats per minute.

There is nothing inherently wrong about training in zone 3, so long as it is beneficial for your race goals. If you are racing in events that are longer than about 2 or 3 hours and shorter than about 6 or 7 hours, you will spend a lot of time in zone 3.

30 to 45 minutes

A true Zone 4 effort cannot be sustained for much longer than 2-4 minutes, a little longer for elite athletes. You will not want to talk in Zone 4, but can manage 1-2 words if you must speak. Some guidelines, like the General Guidelines below, put Zone 4 and 5 into the same category: a Very Hard Unsustainable effort.

The problem with running in zone 4 or 5 is that you can’t run enough mileage if you are going that hard. Slowing down just a bit allows you to run much farther. If you are not able or willing to run more mileage then there is nothing wrong with running in zone 4 or 5.

Many people find that they have to slow way down or even add walking intervals to keep their heart rate in Zone 2. This can be frustrating but it reflects the state of your aerobic system and the fact that a better endurance base needs to be built. So give it time!

Simply put, the 80/20 rule of running training states that 80% of your weekly training time should be done at an easy effort level, with 20% consisting of harder running. The distinction between easy and hard is based on the athlete’s ventilatory ‘threshold’.

After 30 minutes of running, cardiac drift may cause your heart rate to increase so that you have to slow down to maintain that heart rate window of 160-170 bpm.

Athletes often have a lower resting heart rate than others. If you exercise frequently and are reasonably fit, your heart rate may be lower than other people. This isn’t necessarily a bad thing. A low heart rate means your heart needs fewer beats to deliver the same amount of blood throughout your body.

Heart rates essentially stay elevated for longer after these types of training in order to metabolise the lactate that has accumulated and return the body to homeostasis. There is an added bonus with exercise that causes the heart rate to stay elevated for longer, more calories are burned as a consequence.

You can calculate your maximum heart rate by subtracting your age from 220. For example, if you’re 45 years old, subtract 45 from 220 to get a maximum heart rate of 175. This is the average maximum number of times your heart should beat per minute during exercise.