Why Premature Heartbeats Occur During Physical Activity

Experiencing premature heartbeats when starting to walk or engage in physical activity often indicates an underlying structural heart issue. These irregular heartbeats, also known as arrhythmias, may stem from problems related to heart structure, function, or blood supply to the heart muscle. Unlike benign or physiological premature beats that typically occur at rest and disappear with activity, those triggered by exertion usually point to a more serious condition. Below are some of the most common causes:

Coronary Artery Disease (CAD)

Coronary artery disease is one of the leading causes of premature heartbeats during physical activity. When the coronary arteries become significantly narrowed due to plaque buildup, the heart muscle may not receive enough oxygen-rich blood during exertion. This lack of blood flow, known as ischemia, can trigger arrhythmias, including premature ventricular contractions (PVCs) or premature atrial contractions (PACs).

Heart Failure

Conditions such as hypertension, diabetes, and various types of cardiomyopathy can lead to heart failure, which is often accompanied by an enlarged heart and reduced functional capacity. In such cases, the heart may struggle to meet the increased demands of physical activity. This inability to compensate can result in irregular heartbeats, especially during exercise or movement.

Impact of Reduced Cardiac Reserve

As the heart's ability to pump blood diminishes, the body's demand for oxygen during physical activity can quickly outpace supply. This imbalance often leads to electrical instability in the heart, which can manifest as premature beats or more complex arrhythmias.

Heart Valve Disorders

Valvular heart disease is another potential cause of activity-related premature beats. Previously more common due to rheumatic fever, conditions such as mitral stenosis or aortic stenosis can impair blood flow through the heart. In recent years, calcific valve disease—often seen in older adults—has become a more frequent cause. These structural valve abnormalities can disrupt normal heart rhythm during physical exertion.

Key Differentiation: Benign vs. Organic Causes

It's important to distinguish between benign premature beats and those caused by structural heart disease. Physiological premature contractions typically occur at rest and tend to subside with exercise. In contrast, organic causes often result in palpitations that begin or worsen during activity, signaling a need for further cardiac evaluation.

If you frequently experience premature heartbeats during walking or other forms of exercise, it's crucial to consult a healthcare provider for a comprehensive assessment. Early diagnosis and treatment of underlying heart conditions can significantly improve outcomes and reduce the risk of more serious complications.