Tachycardia: prevention, diagnosis and when to see a doctor
A rapid heartbeat is one of the most common complaints that people who train bring to a cardiologist. In most cases the cause is harmless and removable, but a small share of episodes points to an arrhythmia that can be cured only after an accurate diagnosis. The editorial team has gathered practical information: what you can do yourself, what examinations exist and when delay is unacceptable.
Prevention: what depends on the athlete
The first level of prevention is removing the causes of sinus tachycardia related to routine. Adequate hydration before, during and after workouts, especially in the heat, reduces cardiovascular drift. A useful guide is the colour of the urine and the difference in body weight before and after a session: a significant weight loss during a workout means there was too little fluid.
The second factor is sleep and recovery. Chronic sleep deprivation raises sympathetic tone, while a sharp increase in training volume without recovery weeks lowers heart-rate variability. Daily monitoring of the morning pulse or HRV with a chest strap helps to spot the trend before symptoms appear.
The third is a sensible attitude to stimulants. The total daily amount of caffeine from coffee, energy drinks and pre-workout formulas in adults should not exceed the level EFSA considers safe (up to 400 mg per day for healthy adults, up to 200 mg in a single dose). It is worth avoiding combining several stimulants and taking them on an empty stomach before a night’s sleep.
The fourth is giving up substances that directly raise the risk of arrhythmias: clenbuterol, thyroid hormones without indication, anabolic steroids, “fat burners” of unknown composition. The risk here is linked not only to a faster pulse but also to structural changes in the heart that can develop imperceptibly.
- Drink water and electrolytes in line with sweat losses.
- Do not train intensely with a fever or in the acute phase of an infection.
- Control your total caffeine, read the composition of pre-workout products.
- Plan recovery weeks and track your morning pulse.
- Treat anaemia and thyroid disease under a doctor’s supervision.
How to assess a heartbeat episode yourself
It is useful to note the circumstances in which an episode arose: at rest or during exertion, after coffee or an energy drink, suddenly or gradually. Sinus tachycardia usually rises and subsides smoothly, whereas paroxysmal supraventricular tachycardia begins abruptly, as if someone flipped a switch, and stops just as abruptly.
It is worth measuring the pulse at the radial artery or using a heart-rate monitor. If the rhythm is irregular, “chaotic”, it may be atrial fibrillation. Modern smartwatches with a single-lead ECG function sometimes help to capture an episode, but their recordings do not replace a medical ECG and require interpretation by a doctor.
For supraventricular tachycardias the ESC guidelines describe vagal manoeuvres as first aid when the patient is stable. The modified Valsalva manoeuvre (straining followed by raising the legs while lying down) proved more effective than the standard one in the REVERT trial. However, such manoeuvres should be performed only if a doctor has previously explained that your diagnosis allows it.
It is important to record accompanying sensations: dizziness, blackout, pain or pressure in the chest, shortness of breath, fainting. It is these, and not the pulse figure, that determine how urgent help is. A diary of episodes greatly eases further diagnosis.
Diagnosis: what examinations are ordered
The basic examination is a 12-lead resting ECG. It allows signs of pre-excitation syndrome, hypertrophy and repolarisation disturbances to be detected. For athletes there are separate criteria for interpreting the ECG that distinguish training changes from pathological ones, and the doctor must take them into account to avoid false diagnoses.
If episodes are short and rare, a standard ECG may show nothing. In that case daily or multi-day Holter monitoring is ordered, and for rare symptoms — event recorders or implantable loop recorders. The goal is to “catch” the ECG precisely during an attack.
Echocardiography assesses the structure of the heart: wall thickness, chamber sizes, valve function. It helps to distinguish an “athlete’s heart” from hypertrophic cardiomyopathy. A stress test shows how the rhythm behaves during work. If needed, cardiac MRI and an electrophysiological study are used.
Laboratory tests look for extracardiac causes: a complete blood count (anaemia, erythrocytosis), TSH and free T4 (thyroid function), electrolytes (potassium, magnesium), glucose. It is worth telling the doctor honestly about all supplements and drugs, including hormonal ones, because without this information diagnosis may go the wrong way.
When to see a doctor and when to call an ambulance
A planned consultation with a cardiologist is needed if the resting pulse is steadily higher than your usual norm without a clear cause, if heartbeat episodes recur, if the rhythm feels irregular, or if exercise tolerance has dropped sharply. An examination is also advisable before returning to training after myocarditis or a severe viral infection.
Immediate medical help is necessary if tachycardia is accompanied by chest pain, marked shortness of breath, fainting or a pre-syncope state, confusion, or if the attack does not pass and well-being worsens. Fainting during physical exertion is always considered an alarming symptom.
A separate situation is the use of stimulants or weight-loss drugs. If after clenbuterol, high doses of caffeine, thyroid hormones or unknown “fat burners” a strong heartbeat, tremor, muscle cramps or chest pain appear, emergency care is needed. Doctors must be told the name of the drug.
A family history of sudden death at a young age (before 50), cardiomyopathy or channelopathies in relatives is a reason for examination even in the absence of complaints. It is precisely such hereditary conditions that most often lie behind sudden death in young athletes.
| Situation | What to do |
|---|---|
| Pulse raised after coffee, in the heat, with sleep deprivation, without other symptoms | Adjust routine, observe |
| Recurrent episodes of sudden heartbeat | Planned consultation with a cardiologist, ECG, Holter |
| Irregular rhythm | See a doctor soon |
| Fainting, chest pain, shortness of breath | Call an ambulance immediately |
| Heartbeat after clenbuterol, T3, “fat burners” | Emergency care, name the drug |
Treatment and return to sport
Tactics depend on the diagnosis. In sinus tachycardia the cause is treated: anaemia, thyroid function and hydration are corrected, stimulants are withdrawn. Drug-based “slowing” of the pulse without establishing the cause is inappropriate.
Supraventricular tachycardias linked to accessory pathways or the AV node are often treated effectively with catheter ablation. The ESC guidelines regard it as the method of choice for many patients with recurrences, and for athletes it is especially valuable because it makes it possible to avoid permanent medication that reduces performance.
Beta-blockers, sometimes prescribed to control rhythm, are on WADA’s Prohibited List in certain sports (for example, shooting and golf). Athletes who need them for medical reasons require a therapeutic use exemption. The decision is made by the doctor together with the athlete.
Return to training after a diagnosed arrhythmia or myocarditis takes place in stages, with follow-up examinations. Sports cardiology guidelines emphasise an individual decision, shared with the patient, rather than automatic disqualification.
Editorial conclusions
Most episodes of a fast pulse in athletes can be prevented: adequate hydration, sleep, caffeine control and avoidance of dangerous stimulants and hormones noticeably reduce the risk.
Diagnosis goes from simple to complex: ECG, Holter, echocardiography, blood tests. The key task is to record an ECG during an episode and to distinguish sinus tachycardia from an arrhythmia.
Chest pain, fainting, shortness of breath and a strong heartbeat after taking stimulants are reasons to seek help immediately. Modern treatment of most arrhythmias makes it possible to return to sport.
We also recommend reading our materials on the causes of tachycardia in athletes, on the prevention of arrhythmia after caffeine and on monitoring heart-rate variability.
References
- Brugada J, Katritsis DG, Arbelo E, et al. 2019 ESC Guidelines for the management of patients with supraventricular tachycardia. Eur Heart J. 2020;41(5):655–720.
- Pelliccia A, Sharma S, Gati S, et al. 2020 ESC Guidelines on sports cardiology and exercise in patients with cardiovascular disease. Eur Heart J. 2021;42(1):17–96.
- Appelboam A, Reuben A, Mann C, et al. Postural modification to the standard Valsalva manoeuvre for emergency treatment of supraventricular tachycardias (REVERT): a randomised controlled trial. Lancet. 2015;386(10005):1747–1753.
- Drezner JA, Sharma S, Baggish A, et al. International criteria for electrocardiographic interpretation in athletes: consensus statement. Br J Sports Med. 2017;51(9):704–731.
- EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific opinion on the safety of caffeine. EFSA J. 2015;13(5):4102.
- Sheldon RS, Grubb BP 2nd, Olshansky B, et al. 2015 Heart Rhythm Society expert consensus statement on the diagnosis and treatment of postural tachycardia syndrome, inappropriate sinus tachycardia, and vasovagal syncope. Heart Rhythm. 2015;12(6):e41–e63.
- World Anti-Doping Agency. Prohibited List. Montreal: WADA; чинна редакція.
Andriy Melnyk
A strength-sports coach and author of programs for beginner and intermediate levels. Writes about training planning.
