Last Month I went to a heart arrythmia specialist to because I was having heart flutters about an hour after laying down and sleeping. I would experience an intense thumping in my chest and extra heart beats or the beats would to close together or too far apart. This suddendly began in September 2009.
The heart arrythmia specialist was immediately familiar with my sypmtoms after I told him my training regiment. The doctor said I have a “High Vagal Tone” and to de-condition for about a year for my heart to return to normal.
All of this is a result of a high level of physical conditioning(endurance) training. The purpose of the vagal nerve is to calm or suppress the heart rate, but he said I fall into a very small group of athlete’s whose vagal nerve response suppresses the heart rate more than needed.
My heart was 40 beat per minute according to EKG performed in his office. I wore a heart monitor for two days and my heart rate dropped to 31 beats per minute between the hours of 1 - 6 am and usually stayed in the 30s between those hours.
The doctor said he is glad I came to him because other doctors would have either wanted to give me medication or even suggest a pacemaker. He also said if I don’t de-condition and continue with the endurance training that I would likely need a pacemaker in 10 years or less.
He said that I fall into a small category of athlete’s who have this problem and then gave examples of professional athletes that suddenly have cardiac issues along with incident of athletes that suddenly have a cardia arrest with no history of any physical illness.
FYI - In December an NFL player died of cardia arrest that no previous health issues. I don’t recall the person’s name.
As far as training goes, I wasn’t doing anything drastic. Lifting 3 days/week, followed by Tabata sprints or barbell complexes. I wouldn’t consider myself an extreme cario athlete or highly conditioned. I’ve always focused more on strenth and bodybuilding training.
I’ve been training about 23 years, I’m 38 yrs old, but the bottom line is that I am predisposed to this issue regardles of the level of training. Not everyone will ever have an issues. After not doing cardio for the past few months, I feel better.
It’s ironic, I found a type of cardio I “enjoy” and now I shouldn’t do it.
Here is article from the American Heart Association.
http://circ.ahajournals.org/cgi/content/full/114/15/1633
Arrhythmias
Because of the heightened vagal tone that accompanies physical conditioning, trained athletes are known to commonly incur innocent arrhythmias and conduction alterations, such as sinus bradyarrhythmia, junctional rhythm, and first-degree or Wenckebach AV block (Mobitz type I).1,26,46,47 However, the application of ambulatory (Holter) ECG monitoring to trained athletes unexpectedly documented substantial ectopy with frequent premature beats and complex ventricular tachyarrhythmias (including couplets and bursts of nonsustained ventricular tachycardia) in many such individuals.48,49 These findings suggest that a variety of arrhythmias are part of the athleteâ??s heart spectrum (Figure 5). Indeed, such rhythm disturbances have not been associated with adverse clinical events and are usually abolished or substantially reduced after relatively brief periods of deconditioning (as well as during physical training sessions and exercise testing). Even in athletes with heart disease, resolution of ventricular tachyarrhythmias with deconditioning is common and may represent a potential mechanism by which sudden death risk is reduced by withdrawal of these individuals from training and competition,49,50 in accord with consensus panel recommendations.2