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Donating Blood

Runners' Performances often Falter after Donating Blood

Published April 13, 1998, in The Post-Standard.

By Dr Kamal Jabbour, Contributing Writer

The debate continues in the medical and athletic communities on the advisability of runners donating blood. While physicians promise donors a return to normal physical activity within days of donating blood, coaches remain concerned of possible impact on competitive performance.

The American Red Cross reported 6 million volunteer blood donations in 1996 in the United States, from fewer than 10 percent of possible donors. To give blood, a donor must be healthy, be at least 17 years old, weigh at least 110 pounds and pass a simple hemoglobin test. The majority of high school athletes are too young to donate blood, while the majority of college athletes suffer from a chronic iron deficiency.

Red blood cells may be the most recognizable component of blood. They contain hemoglobin, an iron-based protein that carries oxygen from the lungs to the muscles and organs. The immediate effects of donating blood include a reduction in the total volume of blood and its oxygen-carrying capacity.

Athletes report a sudden drop in their performance following a blood donation. The reduction in total blood volume lowers the body's ability to dissipate heat and regulate its temperature. The reduction in red blood cell count reduces the body's ability to carry oxygen from the lungs to the leg muscles. Medical personnel advise donors to drink plenty of fluids, and to increase their intake of iron, to replace the donated blood.

While total blood volume returns to normal within two to three days with proper hydration, it may take up to six weeks to bring the red blood cell count back to pre-donation levels. In the meantime, athletes report a detrimental drop in performance by up to 10 percent. This drop in performance is most visible among distance runners, who rely heavily on aerobic capacity.

Coaches also report a higher incidence of illness among athletes who donate blood. They blame a blood donation on a lowering of white cell count and a reduction in the body's ability to fight infections. An intense training program may exacerbate the loss of immunity and lead to a breakdown. Therefore, many coaches are apprehensive toward blood donations during the competitive season, but encourage their athletes to donate blood between seasons.

Incidentally, the reverse effect of increasing performance can be achieved through blood doping. Autologous blood transfusions, in which the athlete's own blood is removed a couple of months before competition, stored, then re-infused just before competition, can give a significant increase in total VO2max, and therefore performance. Homologous blood transfusions from matched donors to athletes can have a similar impact.

Blood transfusions and drugs that increase red cell count are dangerous, and are considered illegal doping by the International and U.S. Olympic Committees. Infusing blood into a healthy individual increases blood pressure and density, and may lead to a circulation overload, blood clots, phlebitis, strokes, kidney damage and metabolic shock, not to mention the risk of transmitted infectious diseases.

Living and training at high altitude simulates the effects of blood doping. An athlete feels tired and weak at first at a high altitude, similar to the effects of donating blood. Gradually, the body adapts to breathing rarefied air by increasing the red blood cell count. This increase in oxygen-carrying capacity eventually results in improved performance when the athlete returns to low altitude.

The similarity in performance deterioration between donating blood and moving to high altitude suggests a potential hidden benefit to donating blood. An interesting hypothesis suggests that the return to a normal red blood cell count following a donation may not be asymptotic. Instead, the red blood cell count may temporarily overshoot its target level before returning to normal.

If the above hypothesis holds true, it suggests that an athlete can safely donate blood, recover gradually without the risk of overtraining, then peak temporarily for a superior performance before returning to normal. Timing is critical and requires a lot of practice, much to the delight of the local blood banks.

Kamal Jabbour ran his 5k pr of 19:39.8 within a few weeks of donating blood. His RUNNING Column appears in The Post-Standard on Mondays. He maintains The Syracuse Running Page and receives email at

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