Dear Dr Baldwin,
Does donating blood have any impact on athletic performance, and should athletes take any special precautions when they do so?
Thanks,
Don
Dear Don,
Giving blood is an incredible act of altruism and goodwill. Donated blood helps to save countless lives every year. However, giving blood is not without consequences, particularly for endurance athletes. Any athlete who has attempted to compete at a high level within the first few days following blood donation can attest to this. They typically feel like a car running on one fewer cylinders.
For a coach or physician, it’s easy to discourage an athlete from donating blood. However, consider the following: It is estimated that in the United States, every three seconds a patient needs blood for procedures ranging from emergencies to elective surgeries to cancer treatments. Unfortunately, the need for blood often outweighs the available supply. The demand for blood increases each year faster than the rate at which people are donating blood. Fewer than five percent of the eligible donors in the U.S. give whole blood (Mollison et al). Athletes make up a major portion of those eligible to donate. When faced with the choice of performing this noble act vs. doing well in competition, most will choose the latter. It is an unfortunate conflict of interests. But there is hope. I am going to explain how you can do both through proper scheduling of blood donation.
The average person has 10 pints of blood flowing through his or her body. There are four components in blood: red blood cells, white blood cells, platelets and plasma. Red blood cells supply oxygen to various parts of the body, and are the most relevant for athletic performance. The more red blood cells you have in your blood, the more oxygen you’re able to carry to your muscles, and the harder and longer your body can go while exercising. A normal adult has a red blood cell percentage of 40-45 percent.
Athletes often report a sudden drop in their performance following a blood donation. In 1995 Panebianco et al. studied the effects of blood donation in 10 competitive cyclists before and after donating one pint of blood. He measured performance at two hours, two days and seven days post-donation and found that sub-maximal performance was unaffected but maximal performance was decreased for at least one week after blood donation. Anecdotal reports from athletes and coaches say that it can take up to three to four weeks to get back to maximal fitness.
When you donate blood you will be giving one pint (10 percent of your total blood volume). In doing so, you will be decreasing the number of your red cells (oxygen carriers) by one-tenth as well. The fluid (plasma) portion of the blood that has been lost can be replaced fairly quickly (within 24-48 hours) with proper hydration. As this replacement is occurring, the remaining red blood cell concentration is becoming less and less (think of dilution). The body can detect when its red cell percentage is low, and it responds by initiating the production of more red blood cells in the bone marrow. As stated before, this process can take a number of weeks. The molecule released by the kidneys to begin this process is called erythropoietin (the natural form of EPO).
Marvin Adnor, M.D., a hematologist in Framingham, Massachusetts, and medical director for the Boston Marathon, believes that for people who engage in light to moderate exercise, blood donation should not be a concern. In an endurance athlete, blood donation should have virtually no effect on strength or short-burst activities, says Donald Christie, Jr, MD, a sports physician in Lewiston, Maine. As a recovery strategy he recommends hydrating aggressively throughout the day after giving blood. He advises endurance athletes to think of the blood-donation day as a rest day and to tread cautiously the next day because hydration stores may not be replenished and can predispose one to fainting.
Many athletes take regular iron supplements after giving blood. Iron is required for red blood cell formation and oxygen binding on these cells. However, most people receive more than adequate levels of iron in their dietary intake. Adner cautions people from taking iron supplements unless they suffer from iron deficiency or don’t get enough iron in their diet (often vegetarians). A chronic iron surplus can cause deposition of iron in tissues like the liver and the heart, causing long-term damage.
An interesting hypothesis was presented a few years ago by Dr. Kamal Jabbour in the Syracuse Post-Standard. He suggested that an athlete may actually be able to enhance his or her performance by giving blood. Here’s how: After red blood cells are removed from the body, a rejuvenation effort is initiated through the natural production of EPO, as described above. Often, however, this red blood cell production process may not shut off immediately upon reaching pre-donation levels. As a result, the red blood cell concentration may actually overshoot the baseline slightly before eventually returning to normal. Anecdotal evidence relates that this can vary anywhere from four to six weeks after blood donation.
If you would like to donate blood here’s how:
Contact your local blood bank and schedule an appointment for donation. Donors must be in good general health, between 17 to 75 years old and must weigh at least 110 pounds. Upon check-in at the blood center, you will need to present identification and complete a form that asks general questions about you, your health and your lifestyle. A blood-center representative will then take you into a private room, ask you a series of questions and run a basic health check on you. The basic health check may include taking your blood pressure, your pulse, a blood sample for iron levels and your temperature. When this is complete, you will be taken into the donor room to give a pint of blood or a unit of blood components (red cells, platelets or plasma). The process takes about two hours. You may only donate blood every 56 days.
References
Jabbour K: Donating Blood and Runners’ Performance. Syracuse Post-Standard. April 13, 1998
Mollison FL, Engelfried CP, Conteras M: Blood Transfusion in Clinical Medicine, ed 8, Boston Blackwell Scientific Publications, 1997
Panebianco RA, Stachenfeld N, Coplan NL, et al: Effects of blood donation on exercise performance in competitive cyclists. Am Heart J 1995; 130 (4):838-840
Schnirring, L: Donating Blood, What Active People Need to Know. The Physician and Sports Medicine; Volume 29, June 2001
Dr. Andrew Baldwin is a three-time Ironman finisher, a two-time USA Triathlon All-American and a physician in the U.S. Navy. More information can be found at www.tribaldwin.com.
If you have a question for Dr. Baldwin, please e-mail Triathlete Magazine Interactive. Please include “Dr. Baldwin” in the subject line.