Out for Blood
Over the past several years, I have regularly donated blood to the American Red Cross. A well-respected college professor and fellow runner touted the altruistic benefits of being a donor.
Athletes should avoid donation during periods of strenuous training or for several weeks before a competition. Physical activity after donating blood is more taxing. Not only is volume lost, mimicking dehydration, but the overall red blood cell count goes down. Red blood cells contain a protein, hemoglobin, which (facilitated by iron) delivers the necessary oxygen for contracting muscles. The volume component of the blood is replenished in 24 hours with adequate hydration, but the blood’s oxygen-carrying capability takes 4-6 weeks to recover.
Frequent donors must have adequate iron intake because iron is lost with donation. Hemoglobin levels are checked by the Red Cross prior to donation and, if iron-deficiency exists, levels may be low. Minimum hemoglobin value for prospective female donors is 12.5 grams per deciliter; the level for males is 13. Qualified donors can give blood as frequently as every 56 days. The Red Cross recommends iron-rich foods, and some donors take iron supplementation.
Several weeks ago, I ran a race with a finish line above 5000 feet. The air that we breathe at higher altitudes contains less oxygen, and physical activity at elevation is more difficult. We feel more winded at altitude after exertion.
Pre-race, I hypothesized that I could mimic training at altitude by donating blood. I hoped that training for the few weeks after donation with less oxygen available to my muscles would improve performance in the upcoming race at altitude. I assumed that blood donation would be a proxy for training at altitude.
First, a disclaimer: This is written for a lay audience with a curiosity about history and blood donation and physical activity. This post is not meant to be medical advice and does not imply any type of doctor-patient relationship.
Therapeutic bloodletting was a cornerstone of medicine for hundreds of years, from antiquity until the 19th century. Many believed that bloodletting released evil humours from the body, allowing sick patients to recover more quickly. One of the founders of Johns Hopkins Hospital, the esteemed Sir William Osler, recommended bloodletting in his classic, The Principles and Practice of Medicine. With the exception of specific diseases, bloodletting for treatment of generally ill patients is no longer routine.
Today, purported but controversial benefits of intermittent blood donation include decreases in systemic inflammation, heavy metals in the blood, and some types of cancer recurrence. Recent evidence also suggests that reduction of whole blood volume through regular donation reduces cardiac events through reduction of whole body iron. Iron is subject to the Goldilocks principle - both too much (overload) and too little (anemia) iron is bad. We need just the right amount in combination with hemoglobin to facilitate oxygen delivery.
Now back to my original question: Can training after blood donation enhance future performance in a trail running race at altitude?
In summary, there is no evidence that I could find to suggest that blood donation as a training tool improves athletic performance at altitude. In fact, it may impair performance due to the decrease in iron levels associated with donating. Though my hypothesis was debunked, I will continue to donate blood regularly. I like contributing via this potentially life-saving intervention. I will also begin monitoring my own hemoglobin with this kit and supplementing with iron-rich foods as needed.