The lower you endurance base when you arrive at altitude, the greater your altitude adaptation will be.
The surroundings, contentment, may be a factor in your perceived improved running fitness.
TO LIVE OR TRAIN AT ALTITUDE? You can’t train hard while living at altitude--Your legs just can’t train because they outrun the lungs. Oxygen saturation is lower at altitude, about 94 percent at 6,000 feet, compared to 98 percent at sea level. In 1990 three groups of 10 athletes either lived in Deer Valley at 8,200 feet and trained at altitude; lived there but trained in Salt Lake City; or lived and trained in Salt Lake. A lived at 8,200 ft and trained there (high-high) B " " " trained at 4,200 ft (high-low) C " 4,200 and trained there (low-low) Group B were able to train harder. They had all the advantages of living at altitude, but when they trained, they also had the higher oxygen availability from being closer to sea level. Perhaps because of the pace at which they trained, training and living at altitude appeared to be detrimental to performance. A second factor effecting performance is nutritional status. In 1991, we had more women in our sample and the results were inconclusive. We believe the problem was an iron shortage. The women tend to be slightly anemic on arrival at altitude. The iron deficiency at the start results in them not reacting to altitude very well. They just can’t produce the extra red blood cells because they lack the raw material (iron) to make them. Low Ferritin measures, below about 25 are suggestive of low iron stores. Even with good iron stores, it takes 6-12 months to see a meaningful increase in the number of RBCs. Living at altitude gives you some benefit racing against sea level runners. When you compete at sea level however, you’ll have only a small edge: Mostly psychological. Many people decrease food consumption due to suppression of appetite, and nausea. The appetite change means lower glycogen stores. Your VO2 max also falls. An 8 minute mile which was at 70 percent of max at sea level will be at 90 percent at 2,000 meters altitude, (6,300 ish feet). The result, of course, is you burn more glycogen; endurance is lowered because the low glycogen stores are depleted more rapidly. Lactate levels at a set speed will of course be higher. Your threshold pace and VO2 max pace will be slower. Your heart and lungs get a full workout at these slower speeds, but your leg muscles produce less force, they de-train. There is a hormonal response to correct the glycogen situation, Catecholamines, epinephrine especially, is secreted. This gives you a somewhat different high to sea level training, or perhaps it’s just the scenery. Out of necessity, your body will use fatty acids better, and blood glucose...thus sparing some glycogen. Probably the main benefit is you can get a good cardiovascular workout at lower speeds...injury risk is lowered during your typical altitude visit--while you do higher than usual mileage. Decrease the de-training aspect with a few quality sessions. RACING AT ALTITUDE Thinking of arriving in Boulder for two days of relaxation before the race? Think again. Most athletes compete at their worst 24 to 48 hours after arriving at altitude. If you can’t train at altitude for at least two and preferably four to five weeks, your next best choice appears to be to compete immediately. The evidence is subjective, but most athletes tell us they feel worst 24-48 hours after reaching altitude. Professional teams such as the Giants and Raiders reduce this low physical capacity by arriving as close to kick off as their governing body allows. Runners don’t have footballs’ constraints--they can arrive as close to race time as flight time-tables allow. The key reason to compete immediately is the instant reflex of the body to breath deeper and faster, resulting in more air passing into the lungs. All other body reflexes result in a temporary decrease in physical capability. Red blood cell production does increase, but it takes about a week before the extra cells begin reaching the bloodstream. However, within 12-24 hours, to create an immediate, artificially increased RBC concentration, there is a shift in plasma volume; plasma (the blood fluid) leaves the blood vessels, pushing the RBCs from their normal 45 % at sea level closer to 50 %. As a result, hemoglobin might rise from 16 to 17-18. But this increase doesn’t help the athlete. The blood volume is thicker. The body is dehydrated, resulting in reduced cardiac output--a key ingredient in the oxygen carrying equation. There is an acid base change in the blood. You pee out bicarbonate, which is a buffer for lactate--you therefore fatigue earlier. The OXYGEN that hemoglobin can carry = cardiac output x hemoglobin x oxygen saturation x a constant The body attempts to compensate for the decreased oxygen saturation by increasing the other two factors. But the body is stupid initially. Concentrating the blood to raise hemoglobin decreases cardiac output, AND creates heat dissipation problems and loss of muscle function (discussed at length elsewhere in the book).
This essay owes its origins to discussions with Dr. Benjamin Levine of the University of Texas, Southwestern Medical Center, Dallas. (about his work with colleague Jim Stray-Gundursin of the Nordic Ski Team); John T. Reaves, an Exercise Physiologist in Denver; Andrew Young, Ph.D. studying Environmental Medicine with the Army Research Institute; George Brooks, Professor and Director of Exercise Physiology Dept. at U.C. Berkley
Or send $17.95 per book to David Holt at PO Box 543, Goleta, CA 93116. (includes shipping and tax)
Or send $17.95 per book to David Holt at PO Box 543, Goleta, CA 93116. (includes shipping and tax)