|The heart of the problem|
In a 3 hour exam many aspects of my heart were examined and many other measurements were done such as muscle thickness 11.5 to 12 mm (above the norm but expected in endurance athletes), ejection fraction 68% which is good, cardiac output, pulmonary activity.....the list goes on and on.
I had previously mentioned to Doc Olive that sometimes when stopping for a drink on a long run I could here a fast clicking sound....this it turns out is the Mitral valve closing.......'so I guess as long as I can here it then I must be alive'.......he found this comment only vaguely amusing. So getting to the hub of the problem what does one do about MVP?
It can be hereditary and is not in itself a problem but obviously when one strains the heart then there are risks. Essentially the valve doesn't close properly and some blood seeps back into the atrium; the more severe the condition then the effects are magnified leading to irregular heartbeat, fatigue...and even heart failure. There are quite a few documented cases where marathon runners have died who had MVP.....(Chad Schieber- Chicago marathon, 2007). A whole plethora of Cardiovascular societies including the ACC/AHA state that...'athletes with MVP- but without high risk features- can engage in all competitive sports'. I do not have any of the high risk features and it is believed that the athletes that died did. However heat and dehydration are also contributing factors and in fact Doc Olive specifically stated that I must not run in heat.....ever. As you all know I have run in extreme heat in the past so his advice is well noted.
As previously mentioned endurance athletes develop physiologic adaptations and structural remodelling of the heart. Increase in blood volume, dehydration and changes in electrolyte levels in abnormal conditions such as endurance sports can increase the risk of lethal arrhythmia but it is important to state that MVP does not cause sudden death but MR (mitrial regurgitation) can and does when associated with other risk factors and unless monitored MVP can lead to MR. So it is the degree of MVP which is important, mine is very slight but endurance training can introduce high risk factors. As Doc Olive said......'Ne tentez pas le diable'....... 'Don't temp the devil'.
An obvious one is to stop running.......this would be incorrect because one of the recomendations to people who have MVP and don't exercise....is too undertake aerobic exercise be it swimming, cycling or running. A healthy strong heart will save your life.
There is now a large body of evidence that suggests that MVP is either hereditary AND/OR is as a result of a magnesium defficiency. Magnesium is an electrolyte involved in nerve transmission, muscular contraction and especially our old friend adenosine triphosphate or ATP production, the fundamental energy currency of the body. Electrolytes are lost during sweat and low blood magnesium causes muscle fatigue and irregular heartbeat......and the latter is a risk factor in MVP! It is very easy to see how magnesium defficiency can occur when training for and completing in endurance events. Magnesium if not replaced is therefore potentially harmful and a study in 1996 stated a significant decline in dietary magnesium intake in much of the Western World. A further study in France showed an average of 75% of the population had a magneseum deficiency. There are other problems such as type-2 diabetes, ADD, allergies, asthma as well as MVP. All athletes know to take electrolyte replacement drinks for sodium, carbohydrates, potassium, chloride.....and magnesium and yet many of these drinks including Gatorade and Powerade products have no magnesium at all.....and the 'Isostar Long Energy Endurance' drink that I personally use also has no magnesium!
Dr Olive has prescribed additional magnesium for this very reason as MVP is a symptom of chronic magnesium deficiency.
I prefer NOT to temp the devil so I will be taking it. I am grateful to the Mayo clinic for raising my awareness of potential heart defects and I hope my comments here may encourage others to get themselves checked out.
But what of my endurance escapades. Dr Olive has stated, in writing, to my GP that he 'strongly advises me against participating in any endurance or mountain running events or training'. His advice on a personal level was even more direct.......'I have been a Cardiologist for nearly 40 years and at your age and even with this slight risk I would not do this sport if I were you'.
I have much to ponder.