Does heart size affect endurance?
Posted November 24th, 2006 at 7:00 AM by Jeanie Rebb
Section: Health & Fitness, Exercise
What laboratory test is the best predictor of finishing times for a running race of 100 kilometers (62 miles), or more than twice the distance of a marathon)? A study from Yokohama, Japan suggests that it is an echocardiogram to measure the size of your left ventricular heart chamber (British Journal of Sports Medicine, Volume 40, 2006), which determines how much blood your heart can pump with each beat.
This would be expected to predict how fast you can run for short distances in which you have to move so fast that the limiting factor is lack of oxygen. This study is surprising because most athletes believe that the major limiting factor for running very long distances is the amount of fuel you can store in your muscles.
Now we know that the limiting factors for ultra- endurance competitions are similar to those of shorter distances: the time it takes to move oxygen from blood in your lungs to your muscles. This is determined by how much blood your heart can pump and how much oxygen your blood can carry. Since 98 percent of the oxygen in your blood is carried by the hemoglobin in your red blood cells, the higher your red blood count, the more oxygen you can circulate. However, a more important factor is how rapidly your heart can pump blood to your muscles, and this is determined by the strength of your heart muscle.
The longer and harder you train by running, the stronger your heart, and that’s what a thicker left ventricle means. The runners who ran the most miles in training had the strongest hearts and the best finishing times. So if you want to compete in any sport requiring extremes of endurance, you have to spend a lot of time training and you also need to exercise very intensely once or twice a week to strengthen your heart.
***Note: We encourage EVERYONE to see a doctor before altering their diet, taking a supplement and/or performing athletic, fitness or other strenuous physical activity. It is your responsibility to evaluate the accuracy, completeness and usefulness of any information, instruction, opinion or advice contained in the content. Please also see our complete disclaimer.***
This post is written by Dr. Gabe Mirkin, M.D. and was originally published on his blog “Fitness and Health E-Zine”.
Dr. Mirkin is board certified in Sports Medicine and has practiced for over 40 years. He has completed more than 40 marathons and was a talk show host of a nationally-syndicated radio program for about 25 years. For more articles by Dr. Mirkin, please check out: www.DrMirkin.com
Please also be advised that Dr. Mirkin’s opinions and the references cited are for information only, and are not intended to diagnose or prescribe. For your specific diagnosis and treatment, consult your doctor or health care provider.
***Note: We encourage EVERYONE to see a doctor before altering their diet, taking a supplement and/or performing athletic, fitness or other strenuous physical activity. It is your responsibility to evaluate the accuracy, completeness and usefulness of any information, instruction, opinion or advice contained in the content. Please also see our complete disclaimer.***
Tags: dr gabe mirkin, echocardiogram, endurance, heart, heart zie, left ventricular heart chamber, oxygen
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