Sinus tachycardia is a faster‑than‑normal but regular heart rhythm that starts from the heart’s natural pacemaker (the sinus node), usually defined as a heart rate over about 100 beats per minute at rest in adults. It is often a normal response to things like exercise, fever, pain, or anxiety, but can sometimes signal an underlying medical problem if it occurs or persists at rest.

What is sinus tachycardia?

  • It is a sinus rhythm (normal electrical pathway) with an elevated rate, typically above 90–100 beats per minute in adults at rest.
  • The sinoatrial node sends out electrical impulses faster than usual, making the heart beat quicker but still in a regular pattern.
  • Unlike some other tachyarrhythmias, the QRS complexes on ECG remain narrow and the rhythm is usually regular.

Common causes and triggers

Many cases are a normal, temporary body response:

  • Physical exertion, emotional stress, anxiety, or pain.
  • Fever, infection, dehydration, or significant blood loss, where the body increases heart rate to maintain blood flow.
  • Medical issues such as hyperthyroidism, anemia, lung disease, heart failure, or recent heart attack, as well as some medications and stimulants (for example, decongestants, albuterol, caffeine, or illicit drugs).

There is also a form called “inappropriate sinus tachycardia,” where the heart rate is persistently high at rest without a clear cause, often in younger patients, and can be quite bothersome.

Symptoms you might notice

Some people feel nothing; others have noticeable symptoms:

  • Palpitations (awareness of a fast heartbeat), pounding in the chest, or a fluttering sensation.
  • Shortness of breath, chest discomfort, lightheadedness, or fatigue, especially if the rate is high or prolonged.
  • In severe or prolonged cases, fainting or near‑fainting can occur, particularly if there is an underlying cardiac problem.

Diagnosis and medical evaluation

Clinicians usually follow several steps:

  • History and exam to look for triggers (exercise, stress, illness, medications, substance use) and red‑flag symptoms like chest pain, severe shortness of breath, or syncope.
  • Tests may include ECG to confirm sinus rhythm, blood work (for anemia, thyroid, infection, electrolytes), chest imaging, and sometimes ambulatory heart monitoring or echocardiography.
  • The key clinical question is whether the fast rate is an appropriate response (for example to fever) or inappropriate and unexplained.

Treatment and when to worry

Management focuses primarily on the underlying cause :

  • For normal, situational sinus tachycardia from exercise or mild stress, no specific treatment is usually needed beyond rest and hydration.
  • If due to a medical problem (for example, infection, dehydration, anemia, hyperthyroidism, heart failure), treatment targets that condition; the heart rate often improves as the condition is corrected.
  • In inappropriate sinus tachycardia or persistent, symptomatic cases, options can include lifestyle changes (avoiding stimulants, stress management, graded exercise) and medications such as beta‑blockers or other heart‑rate–lowering drugs; in highly selected cases, specialized procedures may be considered.

Seek urgent care or emergency evaluation if a fast heart rate is accompanied by:

  • Chest pain, pressure, or discomfort.
  • Severe shortness of breath, fainting, confusion, or a feeling of impending doom.
  • Known heart disease or very high resting heart rates that do not settle with rest.

Information gathered from public forums or data available on the internet and portrayed here.