By Gabe Mirkin, M.D.
Most researchers believe that exercise helps to strengthen the heart and protect it from disease, but about twenty years ago, doctors noted that some men over 80 who competed in cross country ski races longer than 100 kilometers (60 miles) were at increased risk for an irregular heartbeat called atrial fibrillation (BMJ. 1998 Jun 13; 316(7147): 1784–1785). Extensive studies have since confirmed this increased incidence of atrial fibrillation in healthy older world-class endurance athletes (Scan J Med & Sci in Sports. Nov 21, 2013;24(4):). However, most of these men are healthy athletes and have no obvious problems with their hearts.
Non-exercisers with atrial fibrillation are at significantly increased risk for forming clots, particularly in the brain to cause strokes, so doctors put virtually all patients with atrial fibrillation on medicines to prevent clots and strokes. However, most of the older athletes with atrial fibrillation had no medical problems whatever and were not reported to be suffering clots, strokes or other heart problems.
At this time, most doctors treat atrial fibrillation in all patients, including healthy athletes, with:
- drugs to slow heart rate
- drugs to prevent clots
- electric pacemakers to change the maximum heart rate
They may even use electrical impulses to destroy heart nerves in an effort to change the irregular heartbeat. We do not know if the healthy older athletes need these treatments, but rightfully so, doctors are afraid not to treat the athletes because of the possibility of strokes.
New Study Shows No Heart Damage
A recent study found no evidence of irregular heartbeats from damage to the right ventricular heart chamber in elite lifetime-endurance athletes (Circulation. May 17, 2016;133(20):1927-35). Thirty-three world-class endurance athletes, 30 to 60 years old, training for more than 15 hours per week, received extensive heart function tests that were compared to the same number of healthy men who did not have a regular exercise program.
Of course, the athletes had larger and stronger heart right ventricles, but they had no evidence of damage or potentially harmful effects. Their hearts pumped more blood, beat at a much slower resting rate, and most importantly, had no evidence of the previously reported irregular heartbeats called atrial fibrillation. Athletes with lifelong high training volumes seem to be very unlikely to suffer from heart disease.
Other Evidence of Heart Health Benefits of Exercise
Olympic endurance athletes followed for up to 17 years had no evidence of any damage whatever to the size, shape and function of their main pumping chambers (left ventricles) and suffered no evidence of heart damage or disease (J Am Coll Cardiol. 2010;55(15):1619-1625).
A review of fourteen articles on the life spans and death rates of elite endurance athletes shows that they live longer than the general population, and suffer far less from heart disease (J of Sci and Med in Sport. July 2010;13(4):410–416).
A review of 174 studies shows that gardening, household chores and more strenuous activities are associated with a lower risk of stroke and suffering breast and colon cancer, diabetes and heart disease and that the largest risk reductions come with increasing intensity and duration of exercise (British Med J. August 9, 2016).
Studies Suggesting Heart Damage
Some studies have suggested that chronic intense exercise can damage the heart to cause irregular heartbeats.
One report suggests, without good evidence, that intense exercise may cause scarring in the heart that may increase death from heart disease (Mayo Clinic Proc. June, 2012;87(6):587–595). Another article questions the safety of exercising for more than an hour a day (Mayo Clinic Proc. 2014;89(9):1171-1175). Male participants in a 54-mile (90 km) cross-country skiing program were followed for several years. The faster skiers and those who competed in multiple events were at increased risk for the irregular heartbeat of the upper heart called atrial fibrillation and they also had slower resting heart rates (European Heart Journal, June 11, 2013;34(47):3624 – 3631).
However, they were not at increased risk for the types of irregular heartbeats in the lower heart chambers that are more likely to kill them: ventricular tachycardia and ventricular fibrillation. Furthermore, many other studies show that regular exercise is associated with a reduced risk of atrial fibrillation (Heart, July 27, 2015).
Flaw in Study of Heart Damage in Endurance Athletes
Forty athletes were tested immediately after a 3- to 11-hour cross-country ski race and were found to have right ventricular abnormalities that returned to normal afterwards (Eur Heart J. 2012 Apr;33(8):998-1006). This is what you expect when you exercise any muscle vigorously. Your skeletal muscles are supposed to feel sore after vigorous exercise because all muscles in your body show signs of damage after being vigorously exercised, and that can include your heart muscle.
To make a muscle stronger, you have to exercise so intensely that you damage the z-lines that join the sarcomeres blocks in muscle fibers. You can tell you are doing this when you feel a burning in muscles during exercise and Delayed Onset Muscle Soreness (DOMS) several hours afterwards. Then when the Z-lines heal, you muscle become stronger.
Symptoms of Atrial Fibrillation
People with atrial fibrillation may have no symptoms at all. Common symptoms can include fatigue, palpitations, shortness of breath, lightheadedness, dizziness, chest pain or discomfort and fainting.
Risk Factors for Atrial Fibrillation
Heart disease in master athletes is associated with the same risk factors for heart disease in the general population, such as high cholesterol, blood pressure and blood sugar (Sports Med Open. Aug 9, 2016;2:29). Damaged hearts and irregular heartbeats are associated with obesity; lack of exercise; eating red meat, sugared drinks, sugar-added foods and fried foods; not eating lots of fruits and vegetables; and smoking, drinking alcohol, and taking recreational drugs.
Obesity is a major risk factor for atrial fibrillation (J Am Coll Cardiol. Jul 7, 2015 and JAMA. 2004 Nov 24;292(20):2471-7), but elite endurance athletes are virtually never obese. Athletes are less likely to have high blood pressure, which is a major risk factor for atrial fibrillation (J Am Soc Hypertens. Mar, 2015;9(3):191-6).
Walking, bicycling and regular exercise in older age is associated with decreased risk for heart disease Heart. May 14, 2014;100(13):1043-1049. Not exercising is a major risk factor for atrial fibrillation (Am J Cardiol. 2012 Aug 1;110(3):425-32).
Athletes have low resting heart rates that, by themselves, have not been associated specifically with heart damage, but apparently healthy non-exercising men with slow resting heart rates are at increased risk for atrial fibrillation (Circ Arrhythm Electrophysiol. Aug, 2013;6(4):726-31).
I believe that almost everyone should try to exercise every day. Older athletes can and should continue to compete into their later years, but they need to remember that preventing heart problems involves more than just exercising. You can help to prevent atrial fibrillation with an anti-inflammatory lifestyle:
- Eat lots of fruits, vegetables, nuts and beans
- Avoid red & processed meats, sugared drinks, sugar-added foods, and fried foods
- Lose excess weight if overweight
- Keep hydroxy Vitamin D levels above 30 ng/ml (Current Atherosclerosis Reports. Jan 23, 2017)
- Avoid overtraining
My Current Program
I am 82 years old and ride about 150 miles a week. We ride 30 miles three times a week with a group of fast tandem bicycle riders. On the other four days, I try to do controlled 50-pedal-stroke intervals after about 10 minutes of warm-up riding. If my legs are stiff on any of my four interval workout days, I take the day off or ride very slowly.
Caution: The existing evidence is that intense exercise is good for you, provided that you do not have any underlying disease and a normal heart. Many different factors can damage your heart. While vigorous exercise helps prevent heart disease and long-term heart damage, it does not guarantee protection against irregular heartbeats and heart damage. if you have chest pain or any questions about your health, check with your doctor.