Supraventricular tachycardia (SVT) is a condition where the heart experiences episodes of an abnormally fast rhythm originating from the upper chambers, or atria. During an episode, the heart rate can suddenly jump to 150 to 220 beats per minute, significantly faster than the normal resting rate of 60 to 100 beats per minute. For many people, exercise is not off-limits, but it requires a thoughtful and medically supervised approach. Physical activity is generally considered safe and beneficial, provided the individual’s specific cardiac condition is fully understood and managed.
Understanding SVT and Physical Exertion
Exercise can complicate matters for an individual with SVT because physical exertion naturally increases the heart rate and metabolic demand. When exercising, the body releases catecholamines, such as adrenaline, which stimulate the heart and speed up electrical conduction. This heightened sympathetic nervous system activity can act as a trigger, activating the underlying electrical short circuit responsible for the SVT.
The mechanism of SVT often involves an extra electrical pathway or a re-entry circuit within the heart’s upper chambers. While this electrical anomaly may remain silent at rest, the increase in heart rate and adrenaline during a workout can ignite the circuit, leading to a sudden, rapid heartbeat. Factors like dehydration, electrolyte imbalances, and mechanical stretch of the atrial tissue (e.g., during heavy weightlifting) can also lower the threshold for an episode.
Essential Step: Medical Clearance and Assessment
Before starting or continuing any exercise program, consulting with a cardiologist is mandatory for anyone diagnosed with SVT. General advice cannot replace a personalized risk assessment tailored to your specific heart structure and SVT type. The physician will determine your risk level based on the frequency and severity of your episodes and any other underlying heart issues.
Diagnostic testing plays a central role in understanding how your heart responds to stress. A common procedure is the exercise electrocardiogram (ECG) or stress test, where heart activity is monitored while exercising on a treadmill or stationary bicycle. If episodes are infrequent, a Holter monitor or event recorder may be used over several days or weeks to capture the heart rhythm during daily activities, including exercise. These tests help identify the heart rate threshold and the specific conditions that provoke the SVT, allowing the medical team to create a safe exercise prescription.
Safe Exercise Guidelines and Activity Modification
For individuals who have received medical clearance, the focus should shift to moderate-intensity, steady-state activities that promote cardiovascular fitness without over-stressing the heart. Activities such as walking, swimming, or cycling are often recommended because they allow for consistent heart rate control. Your physician may define a specific target heart rate zone that you should not exceed during your workouts. Using a heart rate monitor during exercise is a practical way to ensure you remain within the prescribed safe zone.
Certain activities may require modification or avoidance entirely. High-intensity interval training (HIIT) and competitive sports involving high levels of adrenaline may be discouraged, as rapid heart rate changes and high excitement can be triggers. Heavy isometric lifting, such as maximal weight training, is also a concern because it often involves the Valsalva maneuver (bearing down), which can trigger an SVT episode. Maintaining proper hydration is important, as dehydration and electrolyte loss can lower the body’s threshold for developing an arrhythmia.
Recognizing and Managing SVT Episodes During Activity
It is important to know the warning signs that indicate exercise should stop immediately. Symptoms requiring immediate cessation of activity include sudden, sustained, and rapid palpitations, severe dizziness or lightheadedness, chest pain or tightness, and shortness of breath disproportionate to the level of exertion. If an episode begins, the first step is to stop exercising, sit down or lie down, and try to remain calm.
Some individuals are taught specific vagal maneuvers by their doctor to attempt to stop the episode. These physical actions stimulate the vagus nerve, which can sometimes slow the heart rate and reset the rhythm. Examples include bearing down as if having a bowel movement (Valsalva maneuver), coughing forcefully, or splashing cold water on the face. If the SVT episode does not convert back to a normal rhythm quickly, or if symptoms are severe, emergency medical attention is necessary. Call emergency services immediately if you experience severe chest pain, prolonged shortness of breath, or feel faint or lose consciousness.