Should you monitor your heart rate when exercising and what will happen if you don’t?
Should you monitor your heart rate when exercising and what will happen if you don’t? We asked a sports medicine doctor and a cardiologist.
Why Monitor Your Heart Rate During Exercise
When you are at rest, your pulse, or heart rate (HR), is between 60 and 100 beats per minute.
When you move, your heart has to beat faster to more efficiently supply your working muscles with oxygen and nutrients. And the harder the load, the faster your pulse. So, first and foremost, your heart rate helps determine how hard you are working.
Find the right workout intensity
People tolerate physical activity differently. For example, a sedentary, overweight person’s heart rate can jump to 120 beats per minute during a walk , while a trained athlete will run at this heart rate at a speed of 9 km/h. By measuring the heart rate, you can determine the appropriate load for both.
Pulse is a fairly objective marker of the intensity of the load. You can also focus on subjective fatigue, that is, how hard it is for a person during the activity. But many people, especially beginners, find it difficult to objectively assess their efforts, and in this case, the pulse can be a good clue.
As a rule, the pulse is taken into account when planning training for cyclic cardio load : running or cycling. In such sports, you can easily adjust the intensity taking into account the heart rate.
For example, you went for a run and noticed that your pulse is 105-110 beats per minute and does not rise after a few kilometers. If you are training for health or planning to develop endurance, this intensity is not enough. So, you can run faster. If you speed up and your pulse is 120-130 beats per minute, you can maintain the chosen pace. Such training will already develop endurance, respiratory and cardiovascular systems.
Of course, you can track your heart rate during strength training, but there is little point in this. When you work with heavy equipment, your heart rate increases, but during rest periods between sets, it slows down again. In strength training, the intensity of the load is calculated differently: taking into account the sets, repetitions, and weight of the equipment you will be working with, and no one usually looks at your heart rate.
Track your progress
Over time, the cardiovascular system adapts to the stress. For example, cardiac output—the amount of blood the heart can pump in one beat— increases .
Thanks to adaptation, the heart no longer needs to contract as often during exercise to provide the tissues and organs with the necessary amount of oxygen, and the pulse at rest and during activity begins to decrease.
We can look at the pulse as an indirect marker of the level of physical fitness. The lower it is under load, the higher the training. For example, a person used to run 5 km at a pace of 6 minutes per kilometer and his average pulse was 149 beats per minute. And after a few months of training, he runs his 5 km at his usual pace and sees that his pulse is now 141 beats per minute. His body now works more efficiently, he has become more resilient.
But here we must take into account that heart rate is affected not only by the level of training, but also by many other factors: ambient temperature, the effects of stimulants such as caffeine, psychological stress and fatigue of the body, and taking medications to lower blood pressure.
For example, if a person did not get enough sleep and drank a glass of coffee before jogging , his pulse may rise significantly higher than usual.
Reduce health risks
Ideally, before you start exercising, you should undergo an examination to find out if your heart is healthy.
The minimum screening for sports is an ECG. It is better to have the test done by a doctor who works with athletes and knows what to exclude and how to conduct a screening survey. Amateurs only need to take it once and, if everything is in order, they can safely play sports. Semi-professionals and professionals should undergo an examination once a year, as well as after an illness.
Unfortunately, few people go to the doctor before buying a gym membership or going for their first run after a 10-year break . And in such a case, your pulse can tell you that something is wrong with you.
For example, if you are not out of breath and feel acceptable, and the fitness watch consistently shows a pulse of 170-180 bpm, there is reason to doubt the health of your heart and still go to a cardiologist. This can be observed with arrhythmia, and this is definitely harmful to the heart.
In addition, a sharp increase in heart rate in response to a usual load may show that something is wrong in your body. For example, if you recently had an acute respiratory viral infection and you see that your heart rate increases more than usual during training, you should postpone intensive training until you recover.
Also, a high heart rate may indicate too much training volume .
If your heart rate is higher than normal both at rest and during training, this may indicate overtraining – a condition in which your body does not have time to recover. In this case, you need to reduce the volume of loads so as not to harm your health.
How to determine the heart rate at which to train
The easiest way is to buy a fitness watch or bracelet and wear it all the time. The gadget will measure your heart rate at rest and during activity and, using its algorithms, will calculate zones for medium and high intensity.
If you don’t trust the devices, you can define the zones yourself.
Use the formula
This method takes into account not only your maximum heart rate, but also your resting heart rate. Use the following calculations:
- Calculate your maximum heart rate. Try Tanaka’s formula: 208 − (age × 0.7).
- Calculate your resting heart rate. It is best to do this in the morning, immediately after waking up.
- Calculate the reserve heart rate: maximum heart rate – resting heart rate.
- Determine the lower and upper limits of the zone: percentage x reserve HR + resting HR.
The average intensity will be 50-70% of the reserve heart rate, and the high intensity will be 70-85% of it. For example, for a 30-year-old person, the maximum heart rate will be 185 beats per minute. If his resting pulse is 60 beats per minute, then the reserve heart rate will be 185 − 60 = 125 beats per minute.
The average intensity corridor for this person will be from 122 (0.5 × 125 + 60) to 147 (0.7 × 125 + 60) bpm, and high intensity – from 147 to 166 (0.85 × 125 + 60) bpm. However, if his resting pulse is, for example, 70 or 80 bpm, the corridor will shift a little.
However, any calculations do not give an accurate picture and, on the contrary, can even mislead you.
In fact, the maximum heart rate does not decrease with age. If a healthy person constantly accelerates the pulse to submaximum values, his heart, blood vessels and nervous system will be ready for an increase in heart rate and age will not affect this in any way. If you use formulas, every year a person will need to train less intensively, while in fact his fitness and capabilities will grow.
For example, I know a 30-year-old man whose pulse never rises above 165 bpm. His easy zone is up to 125 bpm, and then he can no longer breathe through his nose. And there is a 55-year-old man who runs a 3.5-hour marathon with a pulse of 165 bpm, and his maximum pulse is 190 bpm.
Yuri Sdobnikov does not recommend using formulas, so as not to mislead yourself. Instead, you can use a physical test with maximum effort. However, you will have to prepare for this.
Conduct a physical test
This is the most difficult option. It is suitable for those who do not mind working to the maximum and finding out their ceiling not with the help of calculations, but right during training.
This test should not be taken if you are unsure about your heart health or are just starting out.
Start by running at a casual pace for 3-4 weeks, and when you feel ready to push yourself, put on a fitness gadget that tracks your pace and heart rate and go for a run.
Work at a conversational pace for the first 15 minutes. Then turn on the workout recording on your fitness gadget and run for 30 minutes at the fastest speed possible for you.
The last 20 minutes of your test are considered your Lactate Threshold (LT) heart rate. If you calculate 60–70% of that, that will be your most useful, easy intensity heart rate, which will best train your cardiovascular endurance.
Over time, as your endurance develops, your numbers may change. It’s a good idea to repeat these tests periodically. For example, if you notice that your heart rate is lower when you jog at your usual pace, or that you can move faster without getting out of breath.
What heart rate should you exercise with?
It depends on what your goal is.
For health and endurance
According to the World Health Organization, to maintain health, you need to do at least 150-300 minutes a week of moderate intensity or 75-150 minutes of vigorous intensity work. You can also combine them in any suitable combination.
Of course, you can do only gentle exercises, they will also be beneficial . But it is better to include high-intensity loads in the plan, as they provide more benefits for endurance and heart health.
The authors of a systematic review and meta-analysis of 11 studies found that high-intensity interval training was more effective at increasing maximal oxygen consumption, improving the contractility of heart cells (cardiomyocytes), and lowering cholesterol than more relaxed cardio.
Interval training is beneficial for the cardiovascular system because it has a preconditioning effect. That is, the heart trains in conditions of reduced oxygen consumption and blood supply and develops resistance to stress factors.
Incorporate one or two intense workouts into your plan, and you’ll reap even more health benefits. For example, you could plan two 40-60 minute, low-intensity workouts per week at 60-70% of your maximum heart rate, and one interval workout with short sprints during which your heart rate can jump to 85% of your maximum. Just be sure to consider your condition and avoid including HIIT in your plan after an illness. You shouldn’t do such workouts for two weeks after an acute respiratory viral infection .
For weight loss
Many people start cardio workouts to lose weight. First of all, it should be noted that a calorie deficit is necessary for weight loss, and physical activity will not have much effect if you compensate for the energy expended with increased portions.
As for the load itself, for weight loss, the “fat-burning” zone is often chosen – the range from 60 to 70% of the maximum heart rate. Indeed, the intensity of the workout affects what fuel the body will primarily use.
For one study, scientists recruited 36 runners of both sexes and tested at what heart rate they would burn primarily fat and at what heart rate their bodies would switch to carbohydrates.
It turned out that women have the highest consumption of fat reserves at a pulse of 58-74% of the maximum heart rate, and men – at 60-78%. At the same time, the upper and lower boundaries of the zone do not differ in the number of fat calories burned per minute. But when the pulse exceeds these values, the body switches to using carbohydrates.
But whether this will make a difference in terms of weight loss is a big question. For example, one study involving 48 overweight people found that cardio at 70–80% of HRRB helped shed more weight and fat than the same workouts at 50–70 or 40–50% of HRRB.
Any moderate-intensity activity that you can maintain for a long time and do regularly is suitable for weight loss. The main thing is that your pulse is not lower than 60% of your maximum heart rate.
Is it necessary to monitor your heart rate during physical activity?
If you are an amateur athlete, it is not necessary to monitor your heart rate vigilantly. You can roughly determine the intensity of your workout by how you feel.
When you exercise at a moderate intensity, your breathing quickens, but you don’t become out of breath . You can hold a conversation without ceasing the activity, which is why this type of work is sometimes called conversational pace.
At high intensity, you won’t be able to communicate calmly without becoming out of breath – you’ll only be able to say a few words before you’re gasping for air.
If you’re running alone and not going to talk, use your ability to breathe through your nose as a guide to test your intensity.
By focusing on your breathing, you can regulate your load. For example, you started running. At first, you can only breathe through your nose, but then there is not enough air. This means it is too hard. Switch to walking and, as soon as your pulse drops, start running again.
Don’t ignore other factors either. If you’re feeling very short of breath and sore and can’t continue training for as long as you planned, you’ve probably overdone it. Slow down and gradually increase the intensity.
Dizziness during and after exercise can also indicate that you’re working too hard . This is a sign that you need to take a break and perhaps see a doctor .
Is it possible to harm your health if you don’t monitor your pulse?
For healthy people, moderate-intensity exercise will not cause harm, even if you do it every day . High-intensity exercise should be limited to one or two sessions per week, and in this case it will also be beneficial for health and will not harm the heart.
Again, you don’t need to monitor your heart rate to know if you’re pushing yourself too hard. If you’re approaching your limit, your body will tell you to stop.
In most cases, a healthy person simply won’t be able to continue intense exercise long enough to cause harm. The only exception is pre-existing chronic conditions. For example, having inherited cardiomyopathies can lead to sudden cardiac death during high-intensity exercise. Or, if a person with severe coronary atherosclerosis starts to accelerate, they may have a heart attack.
Two studies of more than 1,000 myocardial infarctions found that 4 to 7 percent of patients had been engaged in vigorous physical activity shortly before the event. And it is not known how many of them were aware of their cardiovascular problems.
In general, people without diagnosed cardiovascular disease, diabetes, kidney disease, or osteoarthritis do not need to see a doctor before starting exercise. If you do not experience chest pain, pressure, excessive shortness of breath, dizziness, or joint pain during exercise, you can safely exercise.
If you experience any alarming symptoms during your activity, you should stop it immediately and consult a cardiologist or therapist.
Even if you are diagnosed with some pathology, it does not mean that you will have to give up cardio. Intensive training is not only possible, but also recommended for some cardiovascular diseases.
For example, the authors of a meta-analysis of 17 scientific studies found that HIIT is effective and safe for people undergoing rehabilitation after myocardial infarction and coronary artery disease.
But it is important to note here that in the case of such health problems, a doctor should be the one to allow training, as well as choose its intensity and type.
There are heart diseases and periods of illness, during which it is impossible to perform high-intensity loads. Most often, these are cardiomyopathies, unstable course of a chronic disease or recently suffered acute conditions. In all other cases, HIIT will be useful, even for patients who cannot walk 10 m without shortness of breath. True, their load will be different. For example, the patient will pedal in a lying position and the upper limit of the pulse will be 120 or even 100 beats per minute. And this will lead to an improvement in the quality of life and will help him better tolerate the loads. Everyone can do sports, the only question is how and under what supervision.
So, if you have heart problems, do not try to build safe heart rate workouts on your own. Go to a cardiologist and ask how you should exercise.