Effects of Marathon Running on your Heart

Marathon events are traditionally known to build stamina and improve endurance. However, recent studies indicate that events in which we tend to exert ourselves beyond our physical capacity can have an adverse impact on the heart.

Let's face it. Marathons can be exceedingly strenuous, and can challenge your endurance limits. In such scenarios, your heart has to work harder (pump more blood) for an extended duration to meet the high energy requirements of the body.

This continuous fast beating of the heart for long periods can eventually damage the heart muscle fibers. To put it simply, excessive cardiac strain is inevitable after completing a marathon. In fact, most marathon runners have been reported to suffer from heart problems.

In one study that provided strong evidence of the negative effects of extreme exercise, it was observed that runners after a marathon had significantly high amounts of troponin (up to 1.5 times the normal levels), a protein that usually increases dramatically during a heart attack. The rise in troponin levels may indicate damage to the heart muscle.

However, participating in just one marathon is unlikely to inflict any permanent damage to the heart. For instance, after a marathon, the right ventricle and the right atrium appear to be dilated, and there is reduction in right ventricle contraction.

Inflammation of the heart muscle right after a marathon is also a common phenomenon. All these issues are temporary and usually resolve in 2 - 3 months post marathon. Also, the intensive aerobic training needed to prepare for such events may temporarily cause an enlarged heart.

The tendency to repeatedly take part in marathons, however, can eventually cause scarring of the heart tissue, a biomarker that increases the chances of sudden cardiac death. As revealed in the medical journal, Mayo Clinic Proceedings, as much as 12% of marathon competitors may show patchy myocardial fibrosis due to scar formation in the heart muscle.

Repeated stress from workouts performed for extended periods of time may also cause heart rhythm abnormalities, atrial fibrillation, and cardiomyopathy ('stiff' heart). Frequently doing long duration exercises may also hasten aging of the heart and cause coronary artery calcification.

Research has also proved that athletes who repeatedly participate in grueling endurance events carry a 5-fold risk of atrial fibrillation that may eventually lead to worrisome heart ailments. People with pre-existing heart ailments are also at a greater risk of marathon fatalities.

So, those wanting to run a marathon should first get a complete medical check-up to ensure that they are fit for this extreme exercise.

Heart damage risk in the form of coronary calcification can also occur from repeated marathon running. Coronary calcification, meaning plaque formation in the inner lining of the arteries, can cause a heart attack.

In a German study, around 110 subjects in the age group of 50 - 70 who had been regularly participating in marathon events over the years were checked for plaque deposits in the arteries, and then compared with non-marathon runners.

After taking into consideration the lifestyle, smoking habits, and other heart risk factors in both the groups, it was observed that marathon runners still showed higher amount of arterial plaque build up than non-marathon runners.

In another study, it was observed runners who actively participated and finished at least 25 marathons in the last 25 years showed significant buildup in arterial plaque.

The tendency to take part in marathons without any prior training can also be more damaging to the heart. Running a marathon is not something that you decide one fine morning. Sensible training for months is a pre-requisite prior to running a marathon.

Pre-marathon training increases your endurance and more importantly it 'programs' your heart to effectively deal with the strain of long-distance running. Even our daily exercise routine begins with a warm-up to avoid any sort of injury.

Similarly, proper training will equip your heart to handle the impact of this exhaustive workout. This in turn can help to reduce the risk of heart-related injury associated with marathon running.

In one research, conducted by the Heart and Stroke Foundation of Canada, magnetic resonance imaging was used to detect disturbances in amateur and well-trained runners when running a marathon. MRI results showed that disturbances occurred in larger areas of the heart in people who did not undergo proper pre-marathon training.

On the other hand, well-trained runners carried less risk of heart-related damage resulting from long-distance running. To put it simply, the lesser the duration of training, greater will be the chances of heart damage.

The study also showed that it can take up to 3 months for the heart to heal and return to normalcy. Although, the effect of this chronic exercise on the heart was found to be reversible in amateur runners, frequent stress from repeated marathon participation eventually builds up, and can cause irreparable damage to the heart tissue.

In animal studies, rats that were made to run on a treadmill daily showed formation of scar tissue in their heart. Moreover, they were vulnerable to heart problems such as irregular heartbeats (arrhythmia). The only observation found to be comforting was that the heart resumed functioning normally 2 weeks after the activity was stopped.

However, professional athletes tend to participate in multiple marathon events in a year, thereby giving less time for the heart to recover from this high-impact activity.

Although chances of sudden cardiac deaths while running a marathon are minuscule (around one in every 184,000 runners), the death of Ryan Shay while running the US Olympic marathon trials in 2007 brought to the fore the negative effects of running marathons.

Ryan Shay was a 28-year old professional American marathoner, who had successfully finished at least a dozen long-distance running events in just 7 years from 1999 - 2005. The autopsy revealed heart attack as the primary cause of his death.

Ryan was suffering from pre-existing cardiac hypertrophy (chronic enlargement of the heart muscle), common in competitive athletes, that eventually caused a heart attack due to repeated cardiac stress while running.

Keeping adequate time gap between two consecutive marathons is extremely important to keep heart problems at bay. It is advised that when you participate in a particular marathon event, you need to wait for at least 4 months before you run for your next marathon. For half marathons, ensure a time gap of at least 6 weeks. On the other hand, 10 km runs should be spaced one month apart.

Keep in mind that exercise can never be harmful, provided it is done at moderate intensity and not 'pushed' beyond certain limits. As far as running is concerned, too much is detrimental to the heart. Even those who workout 6 days a week, prefer to run just thrice a week. Studies show that covering a distance of 10 - 15 miles on a weekly basis is enough and can go a long way in keeping your heart healthy.

In an attempt to optimize physical competence, we tend to frequently participate in marathons, long-distance cycling, and even extend our daily workout to long hours. It is at this point when the exercise turns 'lethal', making us susceptible to heart diseases.

Remember, exercise is something that should not make you feel defeated - it should be an enjoyable activity that you would like to experience again.

Disclaimer: The information provided in this story is solely for educating the reader. It is not intended to be a substitute for the advice of a medical expert.