What Controls Your Heart Rate: What You Need to Know

  • 1st Revision: Wasi Karim
  • 2nd Revision: Lucy Walker
  • 3rd Revision: Sheza Asim

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Your heart is a muscular pump, located in your chest, that pumps oxygen-rich blood around your body. It continues to beat till your last breath. However, the speed or rate with which it beats is constantly varying under the influence of different stimuli.  

What is Heart Rate?

Your heart rate is the number of times your heart beats in a minute. According to the British Heart Foundation, as an adult, your heart rate should be between 60 and 100 beats per minute (bpm) at rest. In children, resting heart rate is much higher; at 6-12 months it is 80-140 bpm, while at 3-5 years it is 80-120 bpm.

Resting heart rate (RHR) generally tends to increase with age once you reach adulthood. If you work out, your RHR will tend to get lower as aerobic fitness increases. 

According to MedicineNet, a good RHR for an athlete aged 26-35 is 44-50bpm, while an average person of the same age has a RHR of 71-74bpm. A consistently high RHR is associated with an increased risk of heart disease and premature death.¹,

Measuring Your Heart Rate 

The heart rate is relatively simple to measure with a variety of methods available. It can be done by checking the pulse at one of the pulse points, typically located at the wrist. 

You can feel your heart rate by putting your index and middle fingers on the inside of your wrist (see the picture below). Once you find your pulse, count how many beats you feel in 30 seconds, and multiply that number by 2. Do not use your thumb as this has its own pulse point and it will throw you off.

However, this is often a difficult skill to master without proper training. Heart rate monitors are commercially available from many pharmacies and include everything from dedicated sensors (that are strapped to your chest) such as those by Polar or MyZone, to smart watches and wrist-worn fitness trackers, such as Fitbit or Garmin

Dedicated sensors are generally the most accurate way to measure your heart rate, but convenience and usability will sometimes demand another format. The best sensors for different applications are reviewed here.  

What Controls the Heart Rate?

Your heart rate is set by the sino-atrial node (SAN), the pacemaker of the cardiac muscle. The SAN is a bundle of nerve tissue located at the top of the heart where it joins the superior vena cava (SVC), which is the main vein that carries blood to the upper body.

Heart rate is controlled by the two opposing branches of the autonomic nervous system which influence the SAN. The sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS) work together to maintain balance.

The PNS is connected to the heart via the vagus nerve from the medulla oblongata, which connects the brain stem to the spine and central nervous system. The PNS nerves release the hormone acetylcholine (ACh) to slow the heart rat, also known as a negative chronotropic effect. At rest, the PNS input to the SAN is dominant, therefore holding the RHR at the low rate of approximately 60 bpm.

The SNS is connected to the SAN and the atrioventricular node (AVN) of the heart via the sympathetic cardiac nerve trunk, originating in the brain stem. The SNS nerves release the catecholamine hormone ‘noradrenaline’ to accelerate the heart rate and to increase the force of heart contraction. 

The other catecholamine hormone, adrenaline, is also released from the adrenal glands near the kidneys in response to sympathetic stimulation and this acts, via the bloodstream, to accelerate the heart (these hormones are also called positive chronotropic factors).

You may also hear the terms positive and negative inotropic factors. These affect the strength of the heart’s contraction and the force with which it pumps blood, acting primarily through the AVN. Adrenaline and noradrenaline are also positive inotropic factors. Many heart drugs are designed to mimic the body’s natural chronotropic and inotropic factors.

The SNS and PNS effects on the heart rate are further controlled by a clever feedback mechanism called the baroreceptor (pressure receptor) reflex. Baroreceptors measure blood pressure in the arteries leaving the heart by sensing stretching of the artery walls, and communicate changes in arterial pressure to the medulla oblongata.

This activates either the PNS to slow heart rate if arterial pressure rises too high, or the SNS to increase heart rate and contraction force if the arterial pressure falls. These changes act to restore blood pressure to normal levels.

Factors that Increase Heart Rate

According to OnHealth, The Mayo Clinic and MedicineNet, elevated RHR, also known as tachycardia, can be caused by a range of factors:

  • Age. RHR can change with age, according to some studies, being slightly higher in older people.
  • Gender. On average, the RHR of people assigned female at birth (AFAB)tends to be 2-7 bpm higher than the RHR of people assigned male at birth (AMAB).
  • Overweight and Obesity. As body mass index gets higher, so does RHR. ³ 
  • Drinking coffee. The caffeine in coffee, tea or energy drinks causes a release of adrenaline and leads to a rapid and long-lasting elevation of heart rate (several hours) (Sutter Health, EverydayHealth). 
  • Smoking. Smokers have a higher RHR, smaller heart rate rise during exercise and a much slower recovery of heart rate to RHR after exercise ⁵.  Nicotine in tobacco smoke induces the release of noradrenaline in the heart and thus accelerates heart rate via the SNS ³.
  • Frequent binge drinking. Alcohol causes temporary mild tachycardia but prolonged alcohol use can increase RHR long term, increasing the risk of cardiovascular disease (Alcohol Think Again). 
  • Air temperature and humidity. RHR can increase during hot weather, but usually not more than 10 bpm.
  • Stress and Emotions. Strong feelings of stress, anxiety, or even happiness can raise the RHR. The “fight or flight” response to stress releases adrenaline that elevates the heart rate.
  • Body position. RHR can be 3 bpm higher when sitting versus lying down. Similarly, RHR tends to increase a bit upon standing.
  • Medication: According to WebMD, prescription drugs, such as antidepressants (SSRI, SNRI, tricyclics), antibiotics (azithromycin, levofloxacin, amoxicillin, and ciprofloxacin), decongestants (pseudoephedrine, phenylephrine), thyroid medication and asthma medications (e.g. albuterol, corticosteroid inhalers) can cause elevated heart rate and/or palpitations.  Ask your doctor if you're concerned.
  • Chronic sleep deprivation. According to the NHS, long term sleep deficit raises RHR and is generally very bad news for the heart.  Science Daily reported that even short bursts of sleep deprivation can have a similar effect.
  • Overactive thyroid (hyperthyroidism). With excess thyroid hormones in the bloodstream, tachycardia of 90 bpm or more is common (Medicinenet.com).
  • Anaemia. Your heart pumps more rapidly to compensate for the lower oxygen-carrying capacity of anaemic blood cells.
  • Electrolyte imbalance. Blood electrolytes such as potassium, sodium, calcium and magnesium help trigger and send electrical impulses in the heart. An imbalance in electrolytes can interfere with heart signalling and lead to abnormal heartbeats.

It is well known that exercise increases the heart rate. The fitter you are, the more rapidly your heart rate accelerates and recovers during and after exercise.  In general, regular exercise and increased aerobic fitness should result in a substantially lower RHR for your age.

Implications of a Sustained High Heart Rate

When your heart rate is too high, the heart may not be able to pump enough blood to the rest of your body. This can result in oxygen starvation of your organs and tissues and can lead to the following tachycardia-related symptoms:

  • Shortness of breath
  • Lightheadedness
  • Rapid pulse rate
  • Heart palpitations
  • Chest pain
  • Fainting (syncope).

Complications of elevated RHR depend on the type of tachycardia, how high the heart rate is, how long the tachycardia lasts and if you have any other heart conditions. Types of tachycardia are grouped by the part of the heart originating the problem. They include:

  • Atrial fibrillation. Atrial fibrillation is a rapid, irregular heartbeat starting in the upper chambers of the heart (atria). This is the most common type of tachycardia.
  • Atrial flutter. Here the heart's atria beat very fast but at a regular rate, resulting in weakened contractions of the atria.
  • Supraventricular tachycardia (SVT). This is a fast heartbeat that starts somewhere above the lower chambers of the heart (ventricles). Its cause is faulty circuitry in the heart, usually present from birth.
  • Ventricular tachycardia. A rapid heartbeat starts in the lower chambers of the heart (ventricles). The rapid heart rate doesn't allow time for the ventricles to fill and contract efficiently to pump enough blood to the body. 
  • Ventricular fibrillation. This potentially deadly tachycardia occurs when rapid, chaotic electrical impulses cause the ventricles to “quiver” instead of pumping blood to the body. 

The seriousness of each condition depends on whether or not other heart problems are present. Possible tachycardia complications include:

  • Blood clots, which can cause a stroke or heart attack
  • Inability of the heart to pump enough blood (heart failure)
  • Frequent fainting spells (syncope) or unconsciousness
  • Sudden death, usually only in cases of ventricular tachycardia or ventricular fibrillation

Source: Mayo Clinic.

Reducing Your Heart Rate

Moderate exercise strengthens the heart, making it more efficient so that it does not have to work as hard or beat as fast to accomplish its role of distributing oxygenated blood throughout the body.  

As is the case with most health issues, a healthy heart can be encouraged by a healthy diet and lifestyle (British Heart Foundation). Alongside  an abundance of fresh fruit and vegetables, wholegrains and unsaturated fat, consider adding  regular helpings of fish, which can help lower heart rate. This is possibly because the omega and n-3 fatty acids in fish help to stabilise the electrical activity of heart cells¹ ⁷. On the other hand, it is recommended to avoid fatty or sugary foods, such as processed foods, if at all possible.

Relaxation is an important countermeasure to stress because it activates the “rest and digest” response, which counteracts the “fight or flight” response, which as we’ve seen can elevate heart rate. There are many ways to relax but some of the most popular include meditation, yoga and breathing exercises. Types of meditation include mindfulness, transcendental meditation and Tai Chi (PennHealth).  All require practice and some require training.

Breathing exercises are a great place to start, and some are described by Livestrong and UofM Health including:

  • Belly breathing (a.k.a. diaphragmatic breathing)
  • Box breathing
  • Cleansing breath
  • 4-7-8 breathing
  • Roll breathing
  • Morning breathing

Lastly, you should be limiting your intake of alcohol, nicotine (from tobacco) and caffeine. All three of these boost heart rate as we’ve shown, and cutting them out or at least cutting down will lessen this effect.

Summary

Long term elevation of the resting heart rate can lead to severe complications such as heart disease and even sudden death.  Factors which raise heart rate include stress, diet, medication and smoking. The resting heart rate can be lowered by eating healthily, exercising moderately and managing stress.

References:

  1. Dallongeville, J,, Yarnell, J,, Ducimetière, P,, Arveiler, D,, Ferrières, J,, Montaye, M,, Luc, G,, Evans, A,, Bingham, A,, Hass, B,, Ruidavets, J.B. and Amouyel, P. (2003) Fish consumption is associated with lower heart rates. Circulation. 108(7), pp. 820-5.
  2. Haass M and Kübler W. (1997) Nicotine and sympathetic neurotransmission. Cardiovasc Drugs Ther. 10(6), pp. 657-65.
  3. Kang, S.J., Ha, G.C. and Ko, K.J. (2017) Association between resting heart rate, metabolic syndrome and cardiorespiratory fitness in Korean male adults. J Exerc Sci Fit. 15(1), pp. 27-31.
  4. Lindgren M, Robertson J, Adiels M, Schaufelberger M, Åberg M, Torén K, Waern M, Åberg ND and Rosengren A. (2020) Elevated resting heart rate in adolescent men and risk of heart failure and cardiomyopathy. ESC Heart Fail. 7(3), pp.1178-1185.
  5. Papathanasiou G, Georgakopoulos D, Papageorgiou E, Zerva E, Michalis L, Kalfakakou V and Evangelou A. (2013) Effects of smoking on heart rate at rest and during exercise, and on heart rate recovery, in young adults. Hellenic J Cardiol.54(3), pp. 168-77.
  6. Saxena A, Minton D, Lee DC, Sui X, Fayad R, Lavie CJ and Blair SN. (2013) Protective role of resting heart rate on all-cause and cardiovascular disease mortality. Mayo Clin Proc. 88(12), pp.1420-6.
  7. Streppel, M.T., Ocké, M.C., Boshuizen, H.C., Kok, F.J. and Kromhout, D. (2008) Long-term fish consumption and n-3 fatty acid intake in relation to (sudden) coronary heart disease death: the Zutphen study. Eur Heart J. 29(16), pp. 2024-30.

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This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Dr. Richard Stephens

Doctor of Philosophy (PhD), Physiology/Child Health
St George's, University of London


Richard has an extensive background in bioscience and bioinformatics with a PhD in membrane transport physiology and 28 years of experience in scientific publishing, bioscience research and computational biology.
On moving to Cambridge, UK, in 2015, Richard took the opportunity to broaden the application of his scientific background as well as to explore new avenues of interest. Among other things he mentored students at the Disability Resource Centre at the University of Cambridge and is currently working as an educator, pro bono for the Illuminate charity whilst further developing his writing and presentation skills.

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