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Heart rate – the essentials

Understanding these essentials helps you get more out of your training. You’ll develop a better grasp on how your body works when you combine knowledge with listening to your own feelings during training.

Resting heart rate

Resting heart rate (HR rest) stands for the lowest heart rate when awake and at rest.

It's a good indicator of the development of your aerobic fitness. When your resting heart rate decreases as a result of training in the long run, it is safe to assume that your aerobic fitness has improved.

Individual metric

The important thing about resting heart rate is to monitor how your own HR rest develops. You should not compare it with someone else. The reason for this is that there might be a difference of up to 20 bpm in the HR rest of two persons and yet the one with the higher resting heart rate might be aerobically more fit of the two.

When and how to measure your resting heart rate

It is recommended to measure your resting heart rate in the morning after a rest day. The measurement should be performed in supine position in the morning immediately after waking up.

1. Put on your heart rate sensor. Lie down on your back. Relax.

2. After about 1 minute, start a training session on your heart rate monitor. Choose any sport profile, for example Other indoor.

3. Lie still and breathe calmly for 3–5 minutes. Don’t look at the monitor.

4. Stop the training session on your watch. Check the summary for your average heart rate: this is your resting heart rate.

5. Repeat the test every 1 to 3 weeks following the original setting as closely as possible.

Factors influencing your resting heart rate

There are a great many factors that can affect your resting heart rate. The following are only a few examples to give you some idea of the subject.


Mental or physical stress increases the activity of the sympathetic nervous branch of the autonomic nervous system and respectively decreases the activity of the parasympathetic branch. These can be sensed as an increase in the resting heart rate.

State of mind

Different emotions affect the sympathetic and parasympathetic nervous systems. When you're very calm, the activity of the parasympathetic nervous system lowers your heart rate. When you're very excited, for example feeling aggression, your heart rate goes up. So by controlling your emotions you can also control your resting heart rate indirectly.


Your genome is one of the most important factors affecting the resting heart rate. The effect of genes on the resting heart rate can be seen as a difference of more than 20 beats per minute in two persons of the same age and level of fitness.

Training heart rate

Training heart rate describes the heart rate value that you sustain during exercise at a given moment. By training with varying heart rate instead of always with the same heart rate you'll improve your overall fitness much more efficiently. Improving your basic endurance, which is the foundation everything else is built on, requires training on sufficiently low heart rate.

Aerobic fitness

Aerobic fitness is one of the most important components of endurance performance. It’s measured as the amount of oxygen transported in the blood and pumped by the heart to the working muscles and as the efficiency of the muscles to use that oxygen.

Increasing aerobic fitness means increasing the capability of the heart and the rest of the cardiovascular system in their most important task, which is to provide oxygen and supply energy to your body. Measuring your heart rate while training helps you to improve your aerobic fitness because it eliminates the guesswork and shows you exactly what your effort level is.

Insights to your aerobic capacity and performance

Training heart rate can be expressed for example in beats per minute or as a percentage of your individual maximum heart rate. When training with specific goals, the training heart rate should be adjusted to achieve the desired results.

Monitoring your training heart rate in similar, repetitive exercises provides some estimation on where your aerobic fitness is headed. For example if your heart rate is below the usual value for similar exercises and you feel good, it can be assumed that your daily performance is above the basic level or that your aerobic capacity has developed in the long run.

Maximum heart rate

Maximum heart rate describes the highest possible heart rate a person can achieve under physical exertion.

Indicator of your heart's maximum capacity

When you reach your personal maximum heart rate in your workout, it means that your heart is working at its maximum capacity.

The most common formula used to estimate your maximum heart rate is 220 – age. It holds true for a large part of the population. On the individual level, however, the formula may be off by dozens of beats, which is why you should find your maximum heart rate in an actual training situation or by doing a fitness test (a lab test or a field test).

Heart rate variability (HRV)

Hearts don’t function like Swiss clockworks when it comes to regularity of the beat. Heart rate variability means the variation of the intervals between individual heart beats, and it reflects the effect of the autonomic nervous system activity on the heart.

During physical exertion, heart rate increases and heart rate variability decreases. Conversely, as the body relaxes for instance when you’re reading a book in peace and quiet, or when you’re sleeping, heart rate is usually lower, and heart rate variability is higher.

Hard physical training and, for example, a lot of mental stress can lower heart rate variability compared to your usual level at rest. This is a sign of the body being in an overloaded state and in need of recovery.

Maximal oxygen uptake (VO2max)

VO2max stands for maximal oxygen uptake. It is by definition the maximal rate at which oxygen can be used by the body during maximal physical exertion involving large muscle groups.

VO2max is a good index of aerobic fitness and a good predictor of performance capability in aerobic sports such as distance running, cycling, cross-country skiing, and swimming.

How to measure VO2max?

VO2max can be predicted or measured with various tests, of which some are performed with actual exercise and some at rest. To name a few examples, maximal and submaximal tests are often performed on a treadmill or exercise bike. You can also use the Polar Fitness Test, a simple 5-minute test that is performed at rest.

VO2max can be expressed either as milliliters per minute (ml/min) or this value can be divided by the person’s body weight in kilograms (ml/min/kg).

The relationship between oxygen uptake (VO2) and heart rate (HR) is linear within an individual during submaximal dynamic exercise. When your heart rate goes up, your VO2 goes up.

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