Health Corp.
  
 

Heart Disease and Exercise

  
 
Herman Falsetti, M.D. and Jan Christie, J.D.
 
     
     
 

So, you are a competitive athlete. Your diet is pretty good and you train regularly. You figure you don't have to worry about heart disease. Think again. Coronary artery disease, a narrowing of vessels that carry blood to the heart, kills approximately one million Americans per year. It can happen to you.

When I was asked to write an article about heart disease for Competitor, I immediately called my patient Bill McDermott. A champion ultra marathon runner, Bill never had the slightest concern about risks caused by his competitive efforts. Then, last year he suffered a myocardial infarction (heart attack). When I told Bill about the article, he offered to share his experience as a springboard for discussion of heart disease in athletes.

 
     
 

Bill's Story

 
 

On July 4, 2002, on a plane trip from Los Angeles to New York, I suffered a heart attack. It was caused by a blood clot that blocked one hundred percent of my right coronary artery. It took me completely by surprise. I was fifty-one and had none of the common risk factors. No family history of heart disease, normal blood pressure, a non-smoker, ideal body weight as well as normal cholesterol levels. I've been an athlete my entire life.

That spring I was in peak shape. I had excellent races at both Wildflower and Ironman Utah, extending my triathlon age group winning streak, including four Ironman events, over two years. Then on July 1st I over-exerted myself during a bicycle race in the High Sierras.

  
     
  The Everest Challenge was the first United States Cycling Federation sanctioned competition for the California climbing championships. It's a 220 mile race over two days held near Bishop. There is a 29,000 foot elevation gain. Temperatures were over one hundred degrees. I wanted to win the state jersey. It turned out to be the hardest race I'd ever done. Not only was it hot and long, but aid station support was not sufficient. I gave a hundred percent effort the first day and was severely dehydrated. On the second day, I was just grateful to finish after suffering intense leg cramps, fatigue and other symptoms of dehydration.  
     
 

After the race I felt terrible, but told myself it was no worse than I'd felt many times as an ultra marathon runner. I drove home drinking lots of fluids during the five hour trip. Still I weighed in six pounds below normal on Monday morning.

The following Thursday I got on the plane in Los Angeles for New York. Somewhere over the midwest I felt chest pain but denied the possibility of a heart attack. That evening in New York I did an hour jog / walk with difficulty. The next day I did a twenty mile bike ride also with difficulty. Finally, about forty hours after my chest pain on the plane, myocardial infarction was diagnosed. I had suffered a heart attack. An angioplasty was performed immediately to remove the blood clot and the artery was stabilized with a permanent stent.

 
     
 

Although it is impossible to prove exactly what happened to me, the following factors combined form the most likely explanation:

  
 


1. The duration, intensity, heat and altitude of the two day mountain race elevated my heart rate and blood pressure, causing minor irritation and possible inflammation of the arteries in the heart.

2. Severe dehydration caused a thickening of the blood and increased tendency to clot.

3. A small clot may have occurred during the car trip home from the race. If so, there were no symptoms and the resulting blockage of blood to the artery was less than one hundred percent.

4. On the plane, the clot either initially formed, increased in size or moved further down the artery resulting in critical blockage. Confined seating and reduced air pressure on the plane again caused a drop in blood pressure and increased the chances for a blood clot to develop or grow.

 
     
 

What Bill does now - How athletes live with heart disease.

  
 

Bill, clearly attuned to his body and well educated about the events that occurred, consulted with me upon his return from New York. Lab tests confirm some permanent damage to his heart. However, Bill doesn't feel any different now then he felt before the heart attack - even when he exercises. He wanted to quantify the increased risk of continuing strenuous exercise. He wondered if his experience could happen to anyone. He asked what he might have done differently to prevent his heart attack. After all, he'd done over 100 ultra marathons over forty years. He'd read about the risks of deep vein blood clots while riding in cars or airplanes and wondered about recommendations to take aspirin and move around a lot while traveling.

  
     
 

Bill's story is a case study of heart disease in athletes. I will discuss the general topic of heart disease, and (with Bill's permission) address his questions and my exercise prescription for him.

  
     
 

Almost everyone has chest pain at some time. Ninety percent of chest pain is caused by muscle strain in the chest or heart burn. Narrowing of the artery (coronary arteriosclerosis) is due to deposit of fat-like material in the blood vessel wall. Like Bill, most patients want to know (1)how to delay this narrowing of blood vessels and (2) how to continue exercising when narrowing does occur.

  
     
 

Risk Factors, Red Flags and Screening

  
  The four major risk factors for heart disease are (1) High blood pressure, (2) High cholesterol, (3) Diabetes and (4) Smoking. These conditions can often be treated or reversed.  
  Other questions may raise red flags. These include:

  
 

1. History of heart murmur.
2. Family history of sudden death before age forty.
3. Chest discomfort or pain during exercise.
4. Fainting during exercise.
5. Family history of weakened heart.
6. Family history of Marfan's disease.

  
 

The existence of any of the above factors triggers a thorough physical examination. One of the most meaningful tests is a maximum EKG stress test, which allows you to exercise at your maximum heart rate. This measures your exercise intensity comparable to racing or interval workouts. Most arrhythmia's or abnormalities in electrocardiogram occur in athletes at 85 to 90 percent of maximum heart rate. Sub maximum exercise screening, which is typically conducted in doctors' offices, exercises the heart to only 70 or 80 percent of maximum capacity. Therefore, it is not adequate to screen competitive athletes for heart disease.

  
     
  Static tests such as resting electrocardiogram or chest x-ray usually have little value in screening athletes for heart disease. They may show a large "athletic heart" and/or a predictable low heart rate. If you do endurance events of several hours in duration, you need to reproduce maximum conditions where both heart and lung parameters can be tested in the laboratory.  
     
 

Dehydration - Special Risk

  
  Athletes have larger hearts with larger chambers. The heart ejects more blood with each beat at a slower rate than the general population. With a slow heart rate, there may be slow blood flow to the arteries of the heart. During exercise there are major changes in the amount of water in the blood. Dehydration encourages clot formation. This combination of dehydration and slow blood flow may account for clot formation in normal blood vessels. (Clots may cause decreased blood flow even in normal arteries).  
     
 

Supply and Demand

 
 

In the presence of coronary artery disease, blood vessels don't supply enough blood to exercising heart muscles. Chest pain, death of heart tissue and/or cardiac arrhythmia may result. There is a point where energy needed exceeds the oxidative process, and non-aerobic metabolism begins. At anaerobic threshold, the body perceives a sudden increase in breathing, increased fatigue and burning muscles. The muscles pump large amounts of lactic acid into the blood which is no longer carried away by circulation.

Anaerobic threshold usually occurs at 80 to 85 percent of the maximum heart rate. People without heart disease generally experience muscle fatigue caused by excess lactic acid accumulation. Overall muscle fatigue causes them to stop exercise after twelve minutes or so. People with heart disease experience anaerobic threshold differently. They feel muscle fatigue in the heart at first - before they feel it in the arms, legs as well as the rest of the body. Chest pain or cardiac arrhythmia causes them to stop exercise before there is an overall body build-up of lactic acid. A person with coronary artery disease may have to terminate exercise in five minutes due to chest pain or arrhythmia, even though the leg muscles still feel fresh.

  
     
 

Exercise prescription after cardiac event

 
             
  After a cardiac event such as heart surgery, heart attack or arrhythmia, it is not necessary to stop all exercise. However, it is imperative to train scientifically and use a heart rate monitor. Because the heart's demand usually exceeds the supply of blood at or near anaerobic threshold, a sub-maximal exercise test is mandatory to determine safe exercise heart rates. Usually the safe training heart rate is 20 to 30 beats below anaerobic threshold.  
     
 

(Table 1)

Heart Rate Training Zones as Percent of Anaerobic Threshold

 
 

 

Zone

%

Description

  
     
 

 

1

65-80 This is an easy training zone that promotes active recovery and fat burning. This is also a good zone for warm up and cool down.  
     
    2 80-95 This zone is moderate intensity. It promotes endurance and aerobic conditioning.  
           
    3 95-105 This is the aerobic threshold training zone, a hard training zone which will increase speed. This zone promotes high- intensity aerobic conditioning. Interval training and time training should be done in this zone.  
           
    4 105-Max This zone is for absolute max heart rate, usually a 30-40 second effort. Train in this zone only when peaking or racing.  
           
  Exercise prescription is based on the results of a sub-maximal EKG test. Table 1 shows routine heart rate training zones for a person without heart disease. There are four zones. An athlete with heart disease trains mainly in Zone one. Some training may be done in the lower end of zone two. When heart disease has been diagnosed I initially recommend 15 to 20 minutes of exercise three times a week at a heart rate 20 beats lower than the anaerobic threshold of the general population (see table 1). Duration of exercise is gradually increased to thirty minutes per day three to four times a week. I repeat the sub-maximal exercise test at six weeks. Usually anaerobic threshold improves so that the exercise guidelines may expand. Patients maintain a careful exercise diary which includes resting heart rate in the morning and duration of exercise during the day. The individualized exercise prescription is reviewed regularly and corresponds with the patient's measured anaerobic threshold and recorded daily resting and exercise heart rates.  
     
  My general work out tips for the post cardiac event are 1) always use a heart rate monitor and exercise at an even pace; (2) Drink water and stay hydrated; (3) Avoid isometric exercises such as weight lifting; (4) Consult your doctor about how medications will effect your response to exercise; (5) Consult a doctor before starting exercise and (6) Include a warm-up and cool down in every work-out.  
     
 

Bill's Program

  
     
  Bill Mc Dermott currently trains under my guidance. He wears a hear rate monitor and maintains his heart rate below the limits I set for him. Over the last year my prescribed limit for Bill has increased from a starting point of 85 beats per minute to current level of 150 beats per minute. Bill is now approaching his "normal" (pre-cardiac event) training levels, speed work excepted. For the time being Bill has decided not to resume intense competition. However, since March he has completed with moderate effort in the Catalina Marathon, Wildflower Long Course and World's Toughest Half Ironman.  
     
  Bill says "it's been a little difficult curtailing my natural desire to push to my limits, especially since I actually feel good. But I'm trying to refocus with the ideas that I am just glad to be alive and healthy and there is more than one way to enjoy endurance sports."  
     
  Bill's new mantra is "Run for Fun." Amen to that.  
     
  Dr. Herman Falsetti is a board certified cardiologist and has been a consultant physician to the US postal Service Team, members of the Olympic teams since 1984 as well as a number of amateur and professional athletes. To learn to "Train Smarter Not Harder" go to Dr.Falsetti's web site at: www.drfalsetti.com or call 949-727-1900.  
     
  Jan Christie practiced law as a public defender for 10 years. She has competed at bicycle racing, marathons and triathlons. Currently she is a devotee of yoga, spinning and dog walking.  
           
 
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