24/7 heart rate monitoring

Why do we measure heart rate?

The heart rate is the number of times the heart beats per minute. With each beat, an amount of blood is pumped from the heart into the aorta and pulmonary artery. This results in a wave motion that can be felt further down the vessels. The blood flows through the aorta into the following arteries. This wave can be felt in places where these arteries lie relatively close to the skin. One of these places is the wrist, but the heartbeat can also be felt in the groin, in the back of the knee, on the foot, in the neck and on the temples, for example.
The pulse rate is the number of times per minute that such a wave can be felt in the wrist. The pulse rate is affected by the pumping power of the arteries and veins. The pulse rate is therefore not exactly the same as the heart rate. But for most people the measurements are similar and often these terms are used interchangeably.

High heart rate and tachycardia

For an adult at rest, the heart rate is between 60 and 100 beats per minute. A higher heart rate is not always a bad thing. The heart rate differs per person and per moment.

During exercise, the body needs more oxygen, so the heart beats faster. During exercise, the heart rate can reach 180 or more beats per minute. The heart rate during exercise also differs per person. It is important that the heart rate does not increase too quickly and gradually decreases again when resting.
With a very high heart rate, the heart does not have enough time to fill itself completely with blood. It then pumps out less blood than normal per heartbeat. This can cause complaints such as dizziness, palpitations, inability to exercise or fainting.

At rest, the heart rate can also exceed 100 beats per minute, for example due to fever, anxiety, stress, anger or excitement. A high heart rate can also be caused by alcohol, drugs, smoking or medication.

If the resting heart rate (for a long period of time) exceeds 100 beats per minute, we speak of tachycardia. A consistently high resting heart rate may indicate a cardiac arrhythmia.

Low heart rate and bradycardia

For an adult at rest, the heart rate is between 60 and 100 beats per minute. A lower heart rate is not always a bad thing. Sometimes the heart rate is naturally lower or the heart has adapted through many sports. For example, the heart rate differs per person and per moment.

During sleep, the heart rate is lowest. It can then drop to less than 50 beats per minute. This is because the organs and muscles consume little oxygen.
Exercise makes the heart more muscular and allows it to pump more powerfully. The heart then works more efficiently and therefore has to pump less often. A heart rate below 60 is common in athletes in good shape; this is also called 'athlete's heart'.

A low heart rate is usually not dangerous. A prolonged low heart rate (less than 50 beats per minute) is called bradycardia. Most people with a low heart rate have no complaints. If it is no longer possible to pump enough blood, the brain receives too little blood and oxygen and complaints such as fatigue, dizziness, fainting, concentration or memory problems can arise.

Medical causes for a low heart rate can include:

• A slow thyroid gland
• Medications that lower the heart rate, such as beta-blockers
• Problems with the electrical stimulation of the heart (sinus node or AV node not working properly)
• A heart disease, such as inflammation of the heart, myocardial infarction or heart valve disease
• A complication after heart surgery

Irregular heartbeat

The heart rate adjusts at rest and during exercise. If this adjustment is abnormal, there is an irregular heartbeat and possibly a heart rhythm disorder.

There are several factors that can cause an irregular heartbeat, such as:

• Age: heart rhythm disorders are more common in old age
• Heredity: cardiac arrhythmias are more common in families than in others
• Heart disease: Some heart diseases can cause an irregular heartbeat, such as heart failure or heart valve disease
• Other diseases: for example, an overactive thyroid gland can cause an irregular heartbeat
• Medication or drug use: certain medications and drugs can cause an abnormal heart rhythm

If the heart rhythm is irregular, the heart may be pumping too little blood through the body. The organs then receive too little oxygen. This can make you dizzy or short of breath.

Heart rate measurement via viQtor

viQtor, our 24-hour monitoring solution, is worn on the upper arm. viQtor measures vital values with optical sensors. Heart rate (PR) is measured 24 hours a day using photoplethysmography (PPG), a technique that uses the absorption of light. Light of two different wavelengths is used for this: red (660nm) and infrared (940nm). The light is emitted by LED in the upper arm. Part of the light is absorbed, part is reflected on the vasculature and is then received by a photodiode sensor. The heart rate is then calculated using smart algorithms.
viQtor also measures activity level. On the viQtor platform, the measured heart rate values are related to the activity level. A normal increase in heart rate with an increase in activity level therefore does not lead to alerts or (unjustified) action.

Monitor heart rate remotely

viQtor performs a measurement every minute. Every 5 minutes, the saturation values are sent directly via Vodafone's secure NB-IoT/LTE Cat M1 network to our platform in the cloud. The measurements are analyzed on this platform and then stored securely and pseudonymised. The platform is linked to an online dashboard and an app. Healthcare professionals and informal carers can consult the information there.