Athletic Heart Syndrome

enlarged_heartLike any other muscle, the heart gets stronger with exercise.   Athletic Heart Syndrome is a combination of structural and functional changes that occur in the heart of people who train more than an hour on most days.  Signs include sinus bradycardia (a resting heart rate of fewer than 60 beats per minute), a systolic murmur, and extra heart sounds. ECG abnormalities are common.  No treatment is necessary but it must be distinguished from serious cardiac disorders.  During intensive, prolonged endurance- and strength-training, the body signals the heart to pump more blood through the body to counteract the oxygen deficit building in the skeletal muscles.

Enlargement of the heart is a natural physical adaptation of the body to deal with the high pressures and large amounts of blood that can affect the heart during these periods of time. After time, these pressures cause the muscle mass, wall thickness, and chamber size of the left ventricle of the heart to increase.  Cardiac output, the amount of blood that leaves the heart, is proportional to both the chamber sizes of the heart and the rate at which the heart beats. With a larger left ventricle, the heart rate can decrease and still maintain a level of cardiac output necessary for the body. Therefore, it is very common for athletes to have lower resting heart rates than nonathletes.  My resting heart rate is 45.

About 125 athletes under 35 involved in organized sports die of sudden death in the United States each year, according to the Minneapolis Heart Institute Foundation. The institute tracks such deaths in a national registry.  An analysis of 387 cases from the registry showed the vast majority were cardiac-related. About a quarter involved a condition called hypertrophic cardiomyopathy, which causes an enlarged heart. About 20 percent were from a blow to the chest, such as being hit by a bat or ball.

On Dec. 23, 2008 I had my annual physical, although it had been two years since my last physical exam.  I was looking forward to getting a clean bill of health, a sort of rubber stamp to usher in a new year of racing.  But when my EKG results came up abnormal, all my plans were suddenly put on hold.

I made an appointment with a local cardiologist before I even left my doctor’s office.  I wanted this to be quick.  Go get the suggested echocardiogram and get back to my workouts without losing valuable training time over the holiday break.  But the EKG results alone meant I had to keep my workouts aerobic.  For me, that’s keeping my heart rate under 155.

I met with the cardiologist on Dec. 30 but it turned out to be just a consultation.  The echo had yet to be scheduled…more delays.  He doubted there was any problem because I exhibited no symptoms (chest pains, shortness of breath, etc.).  He also explained that athletes can have negative readings on EKGs caused by the heart being closer to the chest wall than the average person.  Never heard such a thing, but what do I know.  The good news was that he cleared me to train hard, so the next day I was out doing long intervals that push my heart rate to near maximum.

I had my echo on Jan. 7.  Turns out I do have thickening of the heart walls.  Normal thickness is about 1.2 mm.  My left ventricle is 1.4mm on one side and 1.8mm on the other side.  Some of this is probably due to Athletic Heart Syndrome, but I also have high blood pressure.  My dad also has heart disease, so I was given a sample of Benicar and cleared to continue my normal lifestyle of exercise.  That night I took one pill.

The next day, I went for a 17-mile run and suffered terribly.  I couldn’t breathe and felt like I was going to pass out.  It had to be the medication and I wasn’t happy.  So I took myself off the medication and bought a home blood pressure monitor to keep my own records for two weeks.  Turns out I don’t have high blood pressure at all.  In fact, it’s a very normal 128/76 with a resting heart rate of 48 beats per minute.  My cardiologist was simply wrong.  I showed him these results.  He still wanted me to do a stress test on the treadmill.  Those results also came back normal.  $1600 later, I was told there’s nothing wrong with my heart.  I have Athletic Heart Syndrome and I’m perfectly healthy.

In 90 to 95 percent of high blood pressure cases, the cause is unknown. You can have high blood pressure for years without knowing it.  That’s why it’s called the “silent killer” — it creeps up on you. When the cause is unknown, it’s called essential or primary hypertension.  The lesson for everyone is to make sure you get your annual physical and check everything out.  Just because you feel good doesn’t mean everything is working properly.  I’m glad I got to the bottom of this before I start another year of racing.

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One Response

  1. Holter monitor reults showed many periods of 2 to 3 seconds, but one at 5.8seconds at 2 to 3 am while sleeping. I am a 70 year old hard riding bicyclist training 200+ miles per week for race training. I know my rest heart rate is very low, in the 30’s for years. My cardiologist strongly recommended a pacer. I’m having it installed today (9/4/09). I am aware of AHS and still have some doubts about the need of a pacer. Probably too late now.

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