Is bradycardia normal for athletes like me?

Question

Hello doctor,

I am a 35-year-old male weighing 154 pounds and standing 5 feet 6 inches. I have an annual medical check-up, and during my most recent check-up, it was noted that I have bradycardia, with a heart rate of 49 bpm. I

have also manually checked my heart rate and used a pulse meter, with results ranging from 51 to 55 bpm. Over the last eight months, I have been running three times a week for 30 minutes each session. Previously, instead of running, I did sports exercises (static biking) with the same intensity.

One difference now is that I have lost 17 pounds over the past seven to eight months. I have no symptoms related to my health; I feel comfortable and fit. I consulted a cardiologist who said that as long as I do not experience symptoms like fainting or dizziness, my heart rate is okay.

However, the doctor expressed concern about my heart rate at night, as a 24-hour ECG (Holter monitor) showed it dropping to 35 bpm while I was sleeping. The doctor prescribed Terbutaline sulfate (2.5 mg twice a day).

My questions are:

Is bradycardia related to my sports activity?
Could it be related to my weight loss?
Is there any reference regarding the normal heart rate for athletes with a "sports heart" during sleep?

Please advise.

Answer 1

Hello,

Welcome to icliniq.com.

It is quite common and normal for regular athletes to have sinus bradycardia. I have seen some with heart rates as low as 40 to 45 bpm during the day. At night, the heart rate usually slows further and can drop to 35 bpm.

As long as you remain asymptomatic, meaning no lightheadedness, fainting, or collapsing, no further action is required. The bradycardia is not related to weight loss, which could be secondary to increased physical activity and exercise.

If weight loss is not intentional, however, it should be investigated. Weight loss and bradycardia can sometimes be seen in patients with malnutrition or severe depression, but I do not believe that is the case here, as you are doing regular exercise, which is a positive sign. Please be assured.

I hope this helps you.

Thank you.