Running
September 23, 2008 at 4:06 am · Filed under Running
Athletes in endurance events practice a training technique called “living high, training low”. Many years ago, scientists noticed that people who live in the mountains, where the air contains lower levels of oxygen, have higher than normal blood oxygen levels. A limiting factor in events that require endurance is the time it takes to move oxygen from the lungs into the muscles. Since more than 98 percent of the oxygen in the blood is bound to red blood cells, people with high numbers of red blood cells should have higher levels of oxygen and therefore have more oxygen available for their muscles, giving them greater endurance. It appears that living and training at high altitude would improve performance even more, so theoretically, all long distance runners, cross country skiers, bicycle racers and other athletes in endurance sports would benefit from living and training at high altitudes.
However, you can’t train as intensely in the mountains where oxygen is sparse. Lack of oxygen during hard exercise slows you down. One group of researchers decided to see if living at high altitudes would increase red blood cell concentration, and training at low altitude would allow the athletes to take harder workouts. Eleven trained middle-distance runners were tested before an 18-day training session in which they slept in special low-oxygen pressure chambers and trained at sea level with oxygen-rich air (Journal of Applied Physiology, January 2006). The tests were repeated 15 days after the training. The athletes who lived high and trained low had higher maximal oxygen uptakes, higher maximal aerobic power and lower resting heart rates than the control group. The blood of these athletes could carry more oxygen, and the oxygen concentration in their bloodstream would return to normal earlier after intense competitions so their performance would improve.
Dr. Gabe Mirkin has been a radio talk show host for 25 years and practicing physician for more than 40 years; he is board certified in four specialties, including sports medicine. Read or listen to hundreds of his fitness and health reports at http://www.DrMirkin.com
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Tags: altitude, cycling, endurance, running, Trainingaltitude, cycling, endurance, running, TrainingShare This
August 3, 2008 at 6:17 am · Filed under Running
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.
Dr. Gabe Mirkin has been a radio talk show host for 25 years and practicing physician for more than 40 years; he is board certified in four specialties, including sports medicine. Read or listen to hundreds of his fitness and health reports at http://www.DrMirkin.com
Subscribe to my FREE weekly newsletter on fitness, health, and nutrition at http://www.drmirkin.com/email/newssign.asp
Tags: endurance, heart size, marathon, race, running, speed, ultra marathonendurance, heart size, marathon, race, running, speed, ultra marathonShare This
June 13, 2008 at 5:18 am · Filed under Running
A study from the Netherlands shows that sugar in sports drinks slows absorption and increases stomach cramping in running races shorter than 12 miles. (International Journal of Sports Medicine, Volume 26, 2005). Fluids pass through your stomach and are absorbed almost immediately in your intestines. Exercise slows fluid passage from the stomach but does not affect intestinal absorption. Sugar added to drinks can delay stomach emptying to increase risk for cramps.
Another study from the University of Utah, reported in the same journal, shows that taking a salty drink just before exercise increases endurance. Dehydration is the most common cause of fatigue during exercise in fit men and women. This study used salted drinks or placebo (unsalted) drinks with two groups of cyclists, and demonstrated a significant improvement in an endurance time trial as well as better maintenance of blood volume in the group that had the salted drinks.
Anything that increases blood volume should increase endurance. Taking in fluid before exercising increases blood volume, and using salty drinks increases blood volume more than pure water. But a major problem with salty drinks is that they usually taste awful. You can accomplish the same results by drinking water, soda or any other beverage you like and eat a handful of salted peanuts or other salty food before and during your endurance events.
Dr. Gabe Mirkin has been a radio talk show host for 25 years and practicing physician for more than 40 years; he is board certified in four specialties, including sports medicine. Read or listen to hundreds of his fitness and health reports at http://www.DrMirkin.com
Free weekly newsletter on fitness, health, and nutrition.
Tags: endurance, exercise, fitness, race, running, salt, sports drinks, stomach crampsendurance, exercise, fitness, race, running, salt, sports drinks, stomach crampsShare This
