Why Athletes Often Have a Lower Resting Heart Rate—and What It Means

Regular training strengthens the heart muscle, allowing it to pump more blood with each beat. As a result, many athletes record resting heart rates well below the general population average of 60–100 bpm, sometimes as low as 40 bpm.

Resting heart rate (RHR) is measured in beats per minute (bpm) while you are calm and at rest, typically seated or lying down. A lower RHR usually indicates that the heart works efficiently, but an unusually slow rate accompanied by symptoms can signal an underlying condition.

How Exercise Lowers Resting Heart Rate

During physical activity the heart delivers more oxygen‑rich blood to working muscles. Over time, repeated bouts of exercise cause the cardiac muscle to thicken and increase its stroke volume—the amount of blood ejected per beat. Because each beat moves more blood, the heart does not need to beat as often when you are at rest.

A 2018 review of cardiovascular research found that all forms of regular activity reduce RHR, with endurance disciplines such as running, cycling, swimming, and even yoga showing the greatest effect.

Factors That Influence Resting Heart Rate

• Age – RHR typically rises with advancing age.
• Fitness level – More conditioned individuals usually have lower RHR.
• Exercise type, intensity, and duration – Endurance training has the strongest impact.
• Environmental temperature – Hot or humid conditions can elevate heart rate.
• Emotional state – Stress, anxiety, and excitement increase RHR.
• Medications – Beta‑blockers slow the heart; certain thyroid drugs can speed it up.

When Is a Low Heart Rate Too Low?

For most athletes, a low RHR is harmless unless it is accompanied by symptoms such as dizziness, fatigue, fainting, chest discomfort, or shortness of breath. These signs may indicate bradycardia—a condition where the heart beats fewer than 60 bpm and fails to supply adequate blood flow.

If you notice any of these symptoms, especially during or after exercise, consult a primary‑care physician. They can evaluate your history and, if needed, refer you to a cardiologist.

Athletic Heart Syndrome (AHS)

AHS is a benign adaptation in which the left ventricle becomes slightly larger and its walls thicker due to long‑term high‑intensity training. An electrocardiogram (ECG) may show changes, but the condition rarely causes health problems. However, overlap with true cardiac disease can occur, so report any of the following to a health professional:

• Frequent chest pain
• Irregular heart rhythms
• Fainting episodes during exercise

Rarely, athletes collapse from an underlying congenital heart defect rather than AHS.

Monitoring Your Heart Rate

To measure your RHR at home, do it first thing in the morning:

1. Place the tips of your index and middle fingers on the lateral side of the wrist, just below the thumb.
2. Count the beats for a full 60 seconds.

Maximum heart rate (MHR) is the highest rate your heart can sustain during intense exercise. A common estimate is 220 – your age. For a 35‑year‑old, MHR ≈ 185 bpm.

Target‑heart‑rate zones are expressed as a percentage of MHR:

• Moderate intensity: 50 %–70 % of MHR
• High intensity: 70 %–85 % of MHR

Using a heart‑rate monitor helps you stay within these zones. Prolonged training above your calculated MHR can be dangerous; stop immediately if you feel light‑headed, dizzy, or ill.

Bottom Line

Well‑trained athletes often have resting heart rates around 40 bpm, reflecting superior cardiovascular efficiency. While a low RHR is usually a sign of good fitness, it is important to be aware of symptoms that could indicate bradycardia or another heart condition. When in doubt, seek medical advice to ensure your training remains safe and effective.