Heart Rate: Definition, Bradycardia, Tachycardia

Edited By Irshad Anwar | Updated on Jul 02, 2025 06:43 PM IST

What Is Heart Rate?

Heart rate is the clinical measure of heart health, denoting the proper functioning of your heart. Knowing what constitutes a normal heart rate and understanding conditions like bradycardia and tachycardia will help you maintain better cardiovascular health.

Basic Concepts Of Heart Rate

Heart Rate: Definition, Bradycardia, Tachycardia

Heart rate is an expression of how often your heart beats. It can be measured as the:_pulse at the wrist or the neck; numerous types of devices such as ECGs and heart rate monitors.

Normal Heart Rates

Heart rate is influenced by age. In adults, it ranges from 60 to 100 beats per minute. In kids, heart rates tend to be higher, which can be attributed to a faster metabolic rate and a smaller size of the heart.

Physiological Factors Establishing Normal Heart Rate

Some of the other factors that account for abnormal rates of heartbeats include physical condition, age, drug, and the amount, and level of stress. Due to the athletic heart, elite athletes have a lower resting heart rate.

Bradycardia

This is called bradycardia when the rate is normally below 60 beats per minute in a resting heart.

Symptoms Of Bradycardia

The common symptoms of bradycardia are fatigue, dizziness, dyspnoea, and fainting spells.

Causes Of Bradycardia

Damage to the heart muscle, congenital defects in the heart, hypothyroidism, and certain medications such as beta blockers and digoxin are among the main causes of bradycardia.

Diagnosis Of Bradycardia

This is diagnosed through tests such as an electrocardiogram, Holter monitor, and exercise stress tests.

Management Of Bradycardia

Treatment options include bradycardia medications, pacemakers, and lifestyle modifications.

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Tachycardia

The normal resting heart rate is above 100 bpm for adults; thus, tachycardia is considered any heart rate that is more rapid than usual.

Symptoms Of Tachycardia

The common symptoms in people experiencing tachycardia are palpitations, rapid pulse, dizziness, shortness of breath, and chest pain.

Causes Of Tachycardia

Tachycardia may be triggered by heart disease, high blood pressure, smoking, fever, and other stress conditions.

Diagnosis Of Tachycardia

Diagnostic tests will be performed to rule out tachycardia, including ECGs, Holter monitors, and blood tests.

How Is Tachycardia Treated?

Tachycardia is treated with medications, cardioversion, catheter ablation, and lifestyle modifications.

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Bradycardia Vs. Tachycardia

There are different symptoms and causes between bradycardia and tachycardia.
With bradycardia, the heart rate is slow, and with tachycardia, the heart rate is fast.
Heart rate is controlled by the autonomic nervous system and hormones. A high heart rate is achieved by the sympathetic nervous system and a low rate by the parasympathetic system.

Why It's Important To Check Your Heart Rate

Checking heart rate will enable one to establish any likely looming health complications quite early in advance. Tools to trace or monitor heart rate include wearable gadgets and smartphone apps that make it easier to keep a tab on heart conditions.

Recommended video on Heart Rate

Frequently Asked Questions (FAQs)

1. What is the normal resting heart rate of an adult?

A normal rate for a resting heart of any adult is anywhere between 60 and 100 beats per minute.

2. What are the complications of untreated bradycardia?

Major complications of untreated bradycardia include heart failure, low blood pressure, and fainting.

3. Are there lifestyle changes that can control tachycardia?

Lifestyle changes, including stress reduction, quitting smoking, and regular physical activity, can, of course, help in controlling tachycardia.

4. How can bradycardia be diagnosed?

Bradycardia can be diagnosed by tests like ECGs, Holter monitors, and stress tests.

5. What are the common symptoms of tachycardia?

Common symptoms of tachycardia include palpitations, dizziness, shortness of breath, and chest pain.

6. How does the body regulate heart rate?

Heart rate is regulated by the autonomic nervous system, specifically through the balance between sympathetic (fight-or-flight) and parasympathetic (rest-and-digest) signals. The sinoatrial (SA) node in the heart, often called the natural pacemaker, receives these signals and adjusts the heart rate accordingly.

7. What's the difference between heart rate and pulse rate?

Heart rate and pulse rate are often used interchangeably, but there's a subtle difference. Heart rate is the number of times the heart beats per minute, while pulse rate is the number of times blood pressure increases in an artery per minute. In healthy individuals, these are usually the same, but in some heart conditions, they may differ.

8. What is the "lub-dub" sound of the heartbeat?

The "lub-dub" sound is created by the closing of heart valves. The "lub" is the closure of the mitral and tricuspid valves at the start of systole, while the "dub" is the closure of the aortic and pulmonary valves at the start of diastole. These sounds ensure blood flows in the correct direction through the heart.

9. What is the relationship between heart rate and cardiac output?

Cardiac output is the volume of blood pumped by the heart per minute. It's calculated by multiplying heart rate by stroke volume. While increasing heart rate can increase cardiac output, the relationship isn't always linear, as very high heart rates can reduce the time for the heart to fill with blood, potentially decreasing stroke volume.

10. How does emotional state affect heart rate?

Emotions can significantly impact heart rate. Stress, anxiety, or excitement can activate the sympathetic nervous system, increasing heart rate. Conversely, relaxation and positive emotions can activate the parasympathetic system, lowering heart rate. This is why heart rate is often used as a measure of emotional state.

11. What is bradycardia and when is it concerning?

Bradycardia is an abnormally slow heart rate, typically defined as below 60 beats per minute in adults. While it can be normal in athletes or during sleep, it may be concerning if accompanied by symptoms like dizziness, fatigue, or fainting, as it could indicate an underlying heart problem.

12. How do endurance athletes' hearts differ from those of non-athletes?

Endurance athletes often develop larger, more efficient hearts due to regular training. This adaptation, known as "athlete's heart," allows them to pump more blood per beat, resulting in a lower resting heart rate (sometimes below 60 bpm). Their hearts can also increase output more effectively during exercise.

13. What is the relationship between oxygen levels and heart rate?

Low oxygen levels (hypoxia) typically cause an increase in heart rate. This is the body's attempt to deliver more oxygen to tissues by increasing blood flow. However, severe hypoxia can eventually lead to a decreased heart rate as the heart muscle itself becomes oxygen-deprived.

14. How does the thyroid gland influence heart rate?

The thyroid gland produces hormones that affect metabolism and heart function. Hyperthyroidism (overactive thyroid) can cause tachycardia, while hypothyroidism (underactive thyroid) can lead to bradycardia. This is why thyroid function is often checked in patients with unexplained heart rate abnormalities.

15. What is the role of baroreceptors in regulating heart rate?

Baroreceptors are pressure sensors located in the carotid arteries and aortic arch. They detect changes in blood pressure and send signals to the brain, which then adjusts heart rate and blood vessel constriction to maintain stable blood pressure. This is part of the baroreceptor reflex.

16. What is the difference between sinus tachycardia and other forms of tachycardia?

Sinus tachycardia is a normal increase in heart rate (over 100 bpm) originating from the sinoatrial node, often due to exercise or stress. Other forms of tachycardia, like atrial fibrillation or ventricular tachycardia, involve abnormal electrical pathways in the heart and can be more serious.

17. What is the role of the vagus nerve in controlling heart rate?

The vagus nerve is a key part of the parasympathetic nervous system. It slows the heart rate by releasing acetylcholine, which reduces the firing rate of the sinoatrial node. This "vagal tone" is important for maintaining a lower resting heart rate and allowing the heart to rest between periods of activity.

18. How does the body maintain heart rate during blood loss?

During blood loss, the body tries to maintain adequate blood flow by increasing heart rate. This compensatory mechanism, part of the baroreceptor reflex, aims to maintain blood pressure despite the reduced blood volume. However, if blood loss is severe, this mechanism may eventually fail.

19. How do beta-blockers affect heart rate?

Beta-blockers are medications that block the effects of epinephrine and norepinephrine on beta receptors in the heart. This reduces the influence of the sympathetic nervous system, resulting in a lower heart rate. They're often used to treat conditions like hypertension and certain arrhythmias.

20. What is the difference between intrinsic and extrinsic regulation of heart rate?

Intrinsic regulation refers to the heart's ability to beat on its own, controlled by the sinoatrial node. Extrinsic regulation involves external factors like nervous system input and hormones that can modify the heart rate. Both systems work together to fine-tune heart rate based on the body's needs.

21. How does age affect normal heart rate?

As we age, the range for normal resting heart rate changes. Newborns typically have a heart rate of 70-190 beats per minute, which decreases to 60-100 beats per minute in adults. Older adults may have slightly lower heart rates due to decreased physical activity and changes in the heart's electrical system.

22. How does the body adjust heart rate during sleep?

During sleep, especially in deep sleep stages, heart rate typically decreases due to increased parasympathetic activity and decreased sympathetic activity. This allows the heart to rest and recover. However, during REM sleep, heart rate can become more variable and may occasionally increase.

23. How does the menstrual cycle affect heart rate in females?

Heart rate can vary slightly throughout the menstrual cycle due to hormonal changes. It tends to be lowest during menstruation and highest in the luteal phase. These changes are usually subtle and within normal ranges but can be more pronounced in some individuals.

24. What is the effect of altitude on heart rate?

At high altitudes, where oxygen levels are lower, the heart rate typically increases to compensate for the reduced oxygen availability. This is part of the body's acclimatization process. Over time, as the body adapts to the altitude, heart rate may return closer to normal.

25. How does body temperature affect heart rate?

Increased body temperature typically leads to an increased heart rate. For every degree Celsius rise in body temperature, heart rate can increase by about 10 beats per minute. This is part of the body's attempt to dissipate heat by increasing blood flow to the skin.

26. What is tachycardia and what causes it?

Tachycardia is an abnormally fast heart rate, usually defined as over 100 beats per minute at rest. It can be caused by various factors including exercise, stress, fever, certain medications, thyroid problems, or heart conditions. The underlying cause determines whether it's benign or requires medical attention.

27. How does caffeine affect heart rate?

Caffeine can increase heart rate by blocking adenosine receptors in the brain, which leads to increased neuron firing and release of stimulatory neurotransmitters. It also promotes the release of adrenaline, further increasing heart rate. However, regular caffeine consumers may develop tolerance to these effects.

28. What is the effect of dehydration on heart rate?

Dehydration can lead to an increased heart rate. As blood volume decreases due to fluid loss, the heart must beat faster to maintain adequate blood flow and oxygen delivery to tissues. This is why staying hydrated is important, especially during exercise or in hot environments.

29. What is the relationship between heart rate and stroke volume?

Heart rate and stroke volume are inversely related to some extent. As heart rate increases, there's less time for the ventricles to fill with blood, potentially decreasing stroke volume. However, the body can compensate for this through mechanisms like the Frank-Starling law, which increases the force of contraction when the heart is stretched more.

30. How does chronic stress affect heart rate?

Chronic stress can lead to persistently elevated heart rates due to ongoing activation of the sympathetic nervous system. Over time, this can lead to decreased heart rate variability and may contribute to cardiovascular problems. Managing stress is crucial for maintaining heart health.

31. What is heart rate and how is it measured?

Heart rate is the number of times your heart beats per minute. It's typically measured by feeling your pulse at locations like your wrist or neck, or by using devices such as electrocardiograms (ECGs) or wearable fitness trackers. A normal resting heart rate for adults ranges from 60 to 100 beats per minute.

32. What is heart rate variability and why is it important?

Heart rate variability (HRV) is the variation in time between each heartbeat. High HRV is generally associated with better cardiovascular health and a more responsive autonomic nervous system. It's an important indicator of the body's ability to adapt to stress and recover.

33. How does body position affect heart rate?

Changing body position can affect heart rate due to the influence of gravity on blood flow. For example, standing up from a lying position can cause a temporary increase in heart rate as the body works to maintain blood flow to the brain against gravity. This is part of the orthostatic response.

34. What is the role of potassium in regulating heart rate?

Potassium plays a crucial role in heart function, including regulating heart rate. It's essential for the proper electrical functioning of heart cells. Both high (hyperkalemia) and low (hypokalemia) potassium levels can lead to arrhythmias, affecting heart rate and rhythm.

35. What is the effect of nicotine on heart rate?

Nicotine, found in tobacco products, stimulates the release of adrenaline and noradrenaline, leading to an increase in heart rate. It also constricts blood vessels, which can further increase heart rate as the heart works harder to pump blood through narrowed vessels.

36. Can bradycardia ever be beneficial?

Yes, in some cases. Athletes often have lower resting heart rates due to their efficient cardiovascular systems. This type of bradycardia is considered beneficial as it allows the heart to pump more blood with each beat, improving overall cardiovascular efficiency.

37. How does exercise affect heart rate?

Exercise increases heart rate as the body demands more oxygen and nutrients. During physical activity, the sympathetic nervous system becomes more active, causing the heart to beat faster and stronger. After exercise, heart rate gradually returns to normal as the parasympathetic system takes over.

38. How does the body increase cardiac output during exercise?

The body increases cardiac output during exercise through two main mechanisms: increasing heart rate and increasing stroke volume (the amount of blood pumped per beat). This is achieved through sympathetic nervous system activation, which makes the heart beat faster and more forcefully.

39. What is the relationship between heart rate and blood pressure?

Heart rate and blood pressure are related but distinct. While an increase in heart rate often leads to an increase in blood pressure, this isn't always the case. The body can maintain blood pressure even with changes in heart rate by adjusting factors like blood vessel dilation and constriction.

40. How does the respiratory system interact with heart rate?

The respiratory and cardiovascular systems are closely linked. During inhalation, heart rate slightly increases, and during exhalation, it slightly decreases. This phenomenon, known as respiratory sinus arrhythmia, helps to improve the efficiency of gas exchange in the lungs.

41. How does pregnancy affect a woman's heart rate?

During pregnancy, a woman's heart rate typically increases by 10-20 beats per minute. This is due to the increased blood volume and cardiac output needed to support the growing fetus. The heart rate usually returns to pre-pregnancy levels within a few weeks after delivery.

42. What is the relationship between heart rate and life expectancy?

Some studies suggest that a lower resting heart rate is associated with longer life expectancy. This may be because a lower heart rate often indicates better cardiovascular fitness and less stress on the heart over time. However, many other factors also influence life expectancy.

43. How does the circadian rhythm affect heart rate?

Heart rate follows a circadian rhythm, typically being lower at night and higher during the day. This is due to the body's natural 24-hour cycle and changes in hormones, body temperature, and activity levels throughout the day. Understanding this rhythm is important in interpreting heart rate measurements.

44. What is the effect of music on heart rate?

Music can influence heart rate, often reflecting its tempo and emotional impact. Fast-paced or exciting music tends to increase heart rate, while slow, calming music can decrease it. This effect is part of why music is sometimes used in stress reduction techniques.

45. How does cold exposure affect heart rate?

Cold exposure typically causes an initial increase in heart rate as the body tries to maintain core temperature. However, prolonged exposure can lead to a decrease in heart rate as the body's core temperature drops. This is why hypothermia can be dangerous, as it can severely slow heart rate.

46. What is the relationship between heart rate and metabolism?

Heart rate and metabolism are closely linked. A higher metabolic rate often corresponds to a higher heart rate, as the body requires more oxygen and nutrients to be delivered to tissues. This is why conditions that affect metabolism, like thyroid disorders, can also affect heart rate.

47. How does alcohol consumption affect heart rate?

Alcohol can have varying effects on heart rate depending on the amount consumed and individual factors. In the short term, it can increase heart rate. However, chronic heavy alcohol use can lead to heart damage and arrhythmias, potentially causing irregular heart rates.

48. What is the effect of blood viscosity on heart rate?

Blood viscosity can affect heart rate indirectly. Higher blood viscosity (thicker blood) increases the workload on the heart, which may lead to an increased heart rate to maintain adequate blood flow. Conditions that affect blood viscosity, like dehydration or certain blood disorders, can thus impact heart rate.

49. How does the autonomic nervous system balance affect heart rate variability?

Heart rate variability (HRV) is largely influenced by the balance between the sympathetic and parasympathetic branches of the autonomic nervous system. Higher parasympathetic activity generally leads to greater HRV, which is associated with better cardiovascular health and stress resilience.

50. What is the relationship between heart rate and blood oxygenation?

Heart rate and blood oxygenation are closely related. When blood oxygen levels drop, the heart typically beats faster to circulate more oxygen to tissues. This is why pulse oximeters, which measure blood oxygen saturation, often also display heart rate.

51. How does digestion affect heart rate?

After eating, heart rate often increases slightly as blood flow is directed to the digestive system. This is part of the "digestive phase" where the body allocates resources to process food. The increase is usually mild and temporary in healthy individuals.

52. What is the effect of anemia on heart rate?

Anemia, a condition characterized by low red blood cell count or hemoglobin, often leads to an increased heart rate. The heart beats faster to compensate for the reduced oxygen-carrying capacity of the blood, attempting to deliver adequate oxygen to tissues.

53. How does chronic pain affect heart rate?

Chronic pain can lead to persistently elevated heart rates due to ongoing stress and sympathetic nervous system activation. This constant strain can potentially contribute to cardiovascular issues over time, highlighting the importance of effective pain management.

54. What is the relationship between heart rate and cardiac arrhythmias?

Cardiac arrhythmias are abnormal heart rhythms that can affect heart rate. Some arrhythmias, like atrial fibrillation, can cause the heart to beat too fast (tachycardia), while others, like heart blocks, can cause it to beat too slowly (bradycardia). Understanding normal heart rate is crucial for identifying arrhythmias.

55. How does the brain's limbic system influence heart rate?

The limbic system, involved in emotions and memory, can significantly influence heart rate through its connections with the autonomic nervous system. Emotional responses triggered by the limbic system can lead to rapid changes in heart rate, explaining why our hearts might race when we're excited or scared.