Have you ever been sitting quietly, watching television or working at your desk, when suddenly you notice your heart beating faster than usual? Sometimes, you may even feel your heart pounding in your chest without doing any physical activity.
As a physician, I recommend paying attention to these episodes, especially if they happen repeatedly. A fast heartbeat at rest can have several causes, ranging from stress and caffeine to anaemia, thyroid problems or an abnormal heart rhythm.
The important thing is to understand when it may be harmless and when it needs medical evaluation.
1. Stress and Anxiety
Stress can activate your body’s fight-or-flight response, releasing hormones that increase your heart rate. You may notice a racing heartbeat even while sitting still.
If episodes occur during stressful situations, anxiety may be a contributing factor. However, do not automatically assume anxiety is the cause, particularly if the symptoms are new or recurrent.
2. Too Much Caffeine
Coffee, energy drinks, strong tea and certain stimulant-containing products can make your heart beat faster or feel as though it is pounding.
If you experience a racing heartbeat after consuming these drinks, try reducing your caffeine intake and observe whether the episodes improve.
3. Dehydration
When your body lacks adequate fluids, your heart may need to beat faster to maintain circulation. Dehydration can be more likely during hot weather, fever, vomiting or diarrhoea.
Drink fluids regularly unless your doctor has advised you to restrict them.
4. Anaemia or Low Haemoglobin
When haemoglobin levels are low, your blood carries less oxygen than usual. Your heart may compensate by beating faster.
Other symptoms can include fatigue, weakness, breathlessness during activity, dizziness and pale skin. A doctor may recommend a complete blood count (CBC) when anaemia is suspected.
5. Thyroid Problems
An overactive thyroid can increase your heart rate, sometimes even when you are resting. You might also experience excessive sweating, trembling, difficulty sleeping, unexplained weight loss or heat intolerance.
A physician may recommend thyroid function tests based on your symptoms and examination.
6. Low Blood Sugar
Low blood glucose can sometimes trigger a racing heartbeat, sweating, shakiness, hunger or dizziness. This is particularly important for people with diabetes who use insulin or certain glucose-lowering medicines.
If you have diabetes and experience these symptoms, check your glucose level when possible and follow your prescribed hypoglycaemia treatment plan. Do not assume every episode of a fast heartbeat is caused by low blood sugar.
7. An Abnormal Heart Rhythm
Sometimes, a fast heartbeat at rest is caused by an electrical problem in the heart, such as an arrhythmia. You may feel sudden racing, fluttering, pounding or skipped beats.
Episodes that begin and stop abruptly, happen repeatedly or occur alongside dizziness or breathlessness deserve medical assessment. An ECG and, in some cases, a heart rhythm monitor may help identify the cause.
When Should You See a Doctor?
If your heart frequently beats fast while you are sitting or resting, arrange a medical evaluation. Your doctor may review your medications, caffeine intake and medical history and recommend tests such as an ECG, CBC, thyroid function tests or blood glucose testing, depending on your symptoms.
Seek emergency medical care if a racing heartbeat is accompanied by chest pain, significant shortness of breath, fainting or feeling as though you are about to faint.
For additional information, read the NHS guide to heart palpitations and the MedlinePlus overview of heart palpitations.
My Advice as a Physician
A fast heartbeat while sitting still should not be ignored if it is new, persistent or recurring. At the same time, it does not automatically mean you have heart disease.
Pay attention to when episodes happen, how long they last, whether your heartbeat feels regular and whether you have other symptoms. Avoid excessive caffeine and maintain adequate hydration, but do not start heart medicines or stop prescribed medication without medical advice.
If you are also experiencing persistent fatigue, you may find it helpful to read about common medical causes of feeling tired all the time. If you have diabetes or other blood sugar concerns, learn about the effects of high blood sugar on the body.
An accurate diagnosis depends on your symptoms, examination and appropriate investigations. Getting assessed is the safest way to understand why your heart is racing.
Author: Dr. Dileep Verma Diabetologist & Physician | Safal Clinic & Wellness Center, Lucknow
