Palpitations Causes Symptoms and When to Seek Help
A sudden flutter in the chest can stop you in your tracks. One moment you feel normal, the next your heart seems to race, thump, skip, or flip. For many people, palpitations are brief and harmless. For others, they can be a sign that the heart’s rhythm, or something else in the body, needs attention.
Palpitations are not a diagnosis by themselves. They are a sensation. The key question is what is causing that sensation, how often it happens, and whether it comes with warning signs such as chest pain, fainting, or shortness of breath.
This guide explains common causes, what palpitations can feel like, what to track, and when to seek urgent medical help. It is for general information only and does not replace advice from a doctor, pharmacist, or qualified health professional.
What palpitations feel like
Palpitations can feel different from person to person. Some people notice a fast heartbeat. Others feel a single heavy thud, a flutter, or a pause followed by a stronger beat.
Common descriptions include:
A racing heart
A pounding feeling in the chest, throat, or neck
A fluttering or trembling sensation
Missed beats or skipped beats
A sudden “flip” in the chest
A heartbeat that feels irregular
A sensation that the heart is beating too hard, even at rest
Palpitations may last a few seconds, several minutes, or longer. They may happen once and not return, or they may come and go over days or weeks.
They can occur while resting, lying down, exercising, after eating, during stress, or when waking from sleep. Some people feel them more at night because there are fewer distractions and the body is still.
Common causes of palpitations
Many palpitations are linked to everyday triggers. Others happen because of a medical condition or a problem with the heart’s electrical system.
Stress, anxiety, and panic
Stress can make the body release adrenaline. This prepares the body for action and can make the heart beat faster or harder. Anxiety and panic attacks can also cause palpitations, often with sweating, trembling, chest tightness, nausea, or a feeling of fear.
This does not mean the symptoms are “in your head”. The physical sensations are real. The challenge is telling whether the palpitations are mainly stress-related or whether another cause needs checking.
Caffeine, alcohol, nicotine, and recreational drugs
Stimulants can trigger palpitations in some people. These may include:
Coffee, tea, cola, and energy drinks
Nicotine from smoking or vaping
Some recreational drugs, including cocaine and amphetamines
Alcohol, especially larger amounts or binge drinking
The effect varies. One person may tolerate several coffees without symptoms, while another gets palpitations after one strong drink.
Exercise and physical effort
A faster heartbeat during exercise is normal. The heart pumps more blood to supply working muscles. Palpitations during or after exercise may still be harmless, especially if they settle quickly and do not come with other symptoms.
They need more caution if they are new, severe, irregular, or linked with dizziness, chest pain, fainting, or unusual breathlessness.
Lack of sleep and dehydration
Poor sleep can make the body more sensitive to adrenaline and stress hormones. Dehydration can also contribute, especially after vomiting, diarrhoea, heavy sweating, or drinking too much alcohol.
Low fluid levels can make the heart work harder. Electrolyte changes, such as low potassium or magnesium, may also affect rhythm, particularly in people who are unwell or taking certain medicines.
Hormonal changes
Hormonal shifts can make palpitations more noticeable. They may occur around periods, during pregnancy, in perimenopause, or after menopause. Thyroid problems can also play a role.
An overactive thyroid can cause a fast heartbeat, weight loss, sweating, shakiness, and heat intolerance. An underactive thyroid is less commonly linked to palpitations, but it can still affect the cardiovascular system in other ways.
Medicines and supplements
Some medicines can cause palpitations as a side effect. These may include certain asthma inhalers, decongestants, thyroid medicines, some antidepressants, and stimulant medicines used for attention disorders.
Some herbal supplements and weight-loss products can also contain stimulant ingredients. If palpitations start after a new medicine or dose change, do not stop prescribed treatment suddenly unless told to do so. Speak to a pharmacist, GP, or the clinician who prescribed it.
Fever, infection, anaemia, and low blood sugar
The heart can beat faster when the body is under strain. Fever and infection commonly raise the heart rate. Anaemia, where the blood has fewer red blood cells or less haemoglobin than normal, can make the heart work harder to carry oxygen.
Low blood sugar can cause shaking, sweating, hunger, anxiety, and palpitations. This is more likely in people with diabetes using insulin or certain tablets, but it can happen in other situations too.
Heart rhythm problems
Sometimes palpitations are caused by an arrhythmia, which means an abnormal heart rhythm. Arrhythmias range from mild to serious.
Examples include:
Extra beats from the upper or lower chambers of the heart
Supraventricular tachycardia, often called SVT
Atrial fibrillation, where the heartbeat is often irregular and may be fast
Less common rhythm problems from the lower chambers of the heart
A heart rhythm problem is more likely if palpitations are sudden, very fast, irregular, recurrent, or associated with fainting, chest pain, or breathlessness. People with known heart disease should take new palpitations seriously.
Symptoms that may happen with palpitations
Palpitations can happen on their own or with other symptoms. The associated symptoms often matter more than the flutter itself.
Symptoms that may occur include:
Light-headedness
Dizziness
Shortness of breath
Chest discomfort or pressure
Sweating
Nausea
Tiredness after an episode
Shaking or trembling
A feeling of anxiety or panic
Fainting or nearly fainting
A brief skipped beat with no other symptoms is often less concerning than palpitations with collapse, chest pain, or severe breathlessness. Pattern also matters. A one-off episode after too much caffeine is different from repeated episodes that happen without a clear trigger.
When palpitations may be harmless
Palpitations are often less worrying when they are brief, settle on their own, and have an obvious trigger. For example, they may follow a strong coffee, a stressful event, poor sleep, or hard exercise.
They are also more reassuring when:
They last only a few seconds
They do not cause chest pain, fainting, or severe breathlessness
The heartbeat feels regular, just faster than usual
They stop when you rest, hydrate, or calm your breathing
There is no known heart condition
They are not becoming more frequent or more intense
Still, “probably harmless” does not mean “ignore forever”. If palpitations keep returning, feel unusual for you, or cause concern, it is sensible to speak to a GP.
When to seek urgent help
Some symptoms need immediate medical attention. Call 999 or go to A&E if palpitations happen with:
Chest pain, pressure, tightness, or heaviness
Fainting or loss of consciousness
Severe shortness of breath
Sudden weakness, numbness, facial drooping, or trouble speaking
A sustained very fast heartbeat, especially if you feel unwell
Severe dizziness or feeling as if you may collapse
Palpitations after a significant injury or electric shock
Blue lips, extreme sweating, or confusion
Seek urgent medical advice if palpitations are new and you have known heart disease, have had a previous heart attack, have heart failure, or have a family history of sudden cardiac death at a young age.
If symptoms are worrying but not immediately life-threatening, contact NHS 111, your GP, or an out-of-hours service for guidance.
When to book a non-urgent appointment
Book a GP appointment if palpitations:
Keep coming back
Last longer than a few minutes
Are getting more frequent
Wake you from sleep often
Happen during exercise
Come with mild breathlessness, fatigue, or dizziness
Start after a new medicine or supplement
Occur alongside unexplained weight loss, tremor, fever, or heavy periods
Are causing ongoing anxiety or affecting daily life
A GP may ask about the timing, triggers, and symptoms. They may check your pulse, blood pressure, heart sounds, and general health. Depending on the situation, they may arrange tests.
Common checks can include:
An electrocardiogram, often called an ECG
Blood tests, such as thyroid function, full blood count, and electrolytes
A heart monitor worn for a day or longer
A review of medicines, caffeine, alcohol, and other triggers
Because palpitations may not happen during a short appointment, a monitor can be useful. It records the heart rhythm during normal daily life and may capture an episode.
What to track before you speak to a clinician
A simple record can help a health professional work out what is going on. Try to note details soon after an episode, while you still remember them.
Useful details include:
Date and time
What you were doing when it started
How long it lasted
Whether the heartbeat felt regular or irregular
Any symptoms, such as dizziness or chest pain
Caffeine, alcohol, nicotine, or drug use that day
Recent illness, fever, vomiting, or diarrhoea
Stress, poor sleep, or intense exercise
Any new medicines or supplements
If you have a smartwatch or home blood pressure monitor, it may show pulse rate. These devices can be helpful, but they are not perfect. Do not rely on a wearable device to rule out a serious problem if symptoms feel concerning.
What you can do during a mild episode
If palpitations are mild and you do not have red-flag symptoms, simple steps may help.
Try to:
Sit or lie down
Breathe slowly and steadily
Sip water if you may be dehydrated
Avoid more caffeine or nicotine
Notice whether the rhythm feels regular or irregular
Check how long the episode lasts
If palpitations happen during exercise, stop and rest. If they settle quickly and there are no other symptoms, make a note of it. If they keep happening with exertion, arrange a medical review.
Do not attempt forceful manoeuvres, take extra medicine, or use supplements to “reset” your heart unless a clinician has advised it for your specific condition.
How to reduce future episodes
Prevention depends on the cause, but some habits can lower the chance of trigger-related palpitations.
Helpful steps include:
Cutting down caffeine gradually if it seems linked
Avoiding energy drinks
Limiting alcohol
Stopping smoking or vaping with support if needed
Drinking enough fluids
Getting regular sleep
Eating regular meals to avoid long gaps without food
Managing stress with walking, breathing exercises, or talking therapy
Reviewing medicines with a pharmacist or GP if symptoms started after a change
If a medical condition is driving the palpitations, lifestyle changes alone may not be enough. Treating anaemia, thyroid disease, infection, or an arrhythmia can make a major difference.
The key takeaway
Palpitations are common, and many episodes are linked to stress, caffeine, poor sleep, dehydration, or other everyday triggers. They can still feel frightening, especially when they happen suddenly or without explanation.
Pay attention to the pattern and the symptoms around them. Brief palpitations with a clear trigger are often less concerning, but palpitations with chest pain, fainting, severe breathlessness, or a sustained very fast heartbeat need urgent help.
If they keep happening, feel new or unusual, or worry you, book a medical review. A short appointment, a few basic checks, and a clear record of your symptoms can often point to the cause and the safest next step.
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