Resting heart rate of 40: when is it normal and when is it concerning?

A heart rate of 40 beats per minute is not automatically dangerous. In well-trained athletes, it is a sign of a strong, efficient heart that pumps more blood per beat. In someone without an athletic background, that same value can indicate bradycardia, the medical term for an excessively slow heart rate. Whether 40 beats per minute is normal for you depends on your fitness level, age and the symptoms you may or may not experience.

Is a heart rate of 40 normal?

What the medical definition says

A normal resting heart rate for adults lies between 60 and 100 beats per minute. That is the benchmark used by doctors and the Dutch Heart Foundation (official). A heart rate below 60 is officially called bradycardia, but that does not automatically mean something is wrong. Context is everything: a well-trained athlete with 40 beats per minute at rest is generally in excellent cardiovascular condition and has no symptoms at all.

When do we speak of bradycardia

Bradycardia becomes concerning only when the low heart rate is accompanied by symptoms such as dizziness, fatigue or fainting. A healthy athlete who wakes up in the morning with 40 beats per minute and feels fine generally has nothing to worry about. During the night, almost everyone’s heart rate drops further, sometimes below 45 beats per minute. That is entirely physiologically normal. However, anyone who barely exercises and is structurally below 50 would be wise to discuss this with their GP.

Why athletes often have a heart rate around 40

Effect of endurance training on the heart

Regular endurance training literally makes your heart stronger. The heart muscle becomes larger and pumps more blood per beat, so the heart needs fewer beats at rest to supply the body. This higher stroke volume is the direct result of years of consistent training.

Examples from top athletes

Top cyclists like Mathieu van der Poel are known for resting heart rates that sometimes lie below 35 beats per minute. This adaptive capacity is not reserved for professional athletes: recreational athletes who train three to four times per week also see their resting heart rate measurably decrease over months at gyms in Dalen.

Measuring a heart rate of 40: how to do it reliably

Pulse measurement versus smartwatch

You measure your resting heart rate by lightly pressing two fingers on the inside of your wrist, just below the base of the thumb. Count the beats for 30 seconds and multiply by two. Smartwatches like the Garmin Forerunner or Apple Watch measure via optical sensors and are handy for daily use. However, they are less accurate in cold temperatures or with a loose-fitting strap. For the most reliable measurement, the manual pulse check remains a solid choice.

Best moment of the day

Always measure your resting heart rate immediately after waking, while you are still lying quietly in bed. Do not get up yet, do not drink coffee, and avoid immediate screen use. This is the moment when your heart rate is lowest and most stable. Anyone who tracks this daily will see over weeks how training, sleep quality and stress influence this number.

Symptoms that indicate an excessively low heart rate

A heart rate of 40 deserves extra attention as soon as you experience symptoms. Dizziness and a light-headed feeling when standing up are common signals. Extreme fatigue without a clear cause, shortness of breath during light exertion or an irregular pulse are warning signs you should not ignore. In severe cases, someone can faint or briefly lose consciousness. If you experience these symptoms in combination with a low heart rate, always contact a GP.

What Gymsearch data shows about athletes and resting heart rate

Cardio versus strength: effect on resting heart rate

In comparing more than 320 Dutch gyms on Gymsearch.nl, we see a consistent pattern: athletes who train at least three times per week structurally report a lower resting heart rate than people who exercise sporadically. Strength training lowers resting blood pressure and reduces the load on the heart, which in the longer term also results in a lower resting heart rate.

Which type of gym suits your goal

If you want to actively lower your resting heart rate, a combination of cardio and strength is most effective. Chains like Basic-Fit, SportCity and Pure Gym offer both disciplines in an affordable membership. Boxing gyms and CrossFit boxes in cities such as gyms in Amsterdam, gyms in Utrecht and gyms in Rotterdam add interval training, which further accelerates cardiac adaptation.

When should you see a GP about a heart rate of 40?

Make an appointment with your GP if you have a heart rate of 40 in combination with dizziness, fainting, extreme fatigue, shortness of breath or an irregular heart rhythm. If you are not an active athlete and are structurally below 50 beats per minute, a check-up is sensible anyway. A low heart rate can sometimes be the result of thyroid problems, certain medications or a conduction disorder in the heart. The WHO (official) provides reliable guidelines on when medical investigation is necessary.

This article is intended solely as general information and does not replace professional medical advice. If in doubt about your heart rate, always consult a doctor.

A heart rate of 40 is a number that should never be assessed in isolation from its context. For the dedicated cyclist or marathon runner, it is evidence of years of efficient training. For someone who barely exercises and experiences symptoms, it is a signal that deserves serious attention. Measure consistently, know your own body, and have yourself checked at the slightest doubt.

Frequently asked questions

Is a heart rate of 40 normal?

A heart rate of 40 is normal for well-trained endurance athletes. Their heart pumps so efficiently that it needs fewer beats per minute. For untrained people, a resting pulse of 40 can indicate bradycardia. If you also have symptoms such as dizziness, fatigue or fainting, a visit to the GP is sensible.

What is an alarming heart rate?

An alarming low heart rate begins below 40 beats per minute, especially if you are not an athlete. It becomes more dangerous if you also have symptoms: fainting, severe fatigue, shortness of breath or chest pain. This can indicate a serious heart problem. With this combination, seek medical help immediately.

What should you do if your heart rate is too low?

If you notice that your resting pulse is structurally around 40 or lower and you have symptoms, see your GP. They can perform an ECG to determine the cause. Never adjust medication yourself. With acute symptoms such as fainting, go directly to the emergency department.

What is the lowest heart rate ever measured in an athlete?

The lowest known resting pulse in a top athlete is 28 beats per minute, measured in cyclist Miguel Indurain. Some sources even mention 27 beats per minute in other athletes. For comparison: an average adult is between 60 and 100 beats per minute. For recreational athletes, 40 to 60 is considered excellent.

Can a heart rate of 40 recover on its own?

A heart rate of 40 rarely recovers on its own if there is an underlying medical cause, such as a conduction disorder or certain medications. In athletes, it is not a problem that needs to recover. Never stop medication on your own without consulting a doctor. An ECG at the GP helps to find the cause.