Blood Donations
(From Race Walking Contact magazine, Dec 2009, sent in by Joff Hulbert)
Endurance athletes should give blood but not before a race. Giving blood will reduce performance significantly if not advanced-planned and factored correctly within one's training protocols. When an athlete donates blood, 500 milliliters of fluid is lost, approximately 70 grams of hemoglobin (='s 220 mg.Iron) and millions of red blood cells. The fluid loss comes back within a few hours, but restoration of the red blood cells takes several weeks. If you are iron-poor, it takes even longer, and is a medical consideration since a few high-mileage ultra-athletes tend towards iron-poverty from training demands.
A blood donation consists of 500 ml, a little over 16 fluid ounces. The loss of 70 grams of haemoglobin [220 mg. of iron] alone takes at least 3 weeks to replace in the healthiest of athletes, but may not fully rebound (till) nearly 6 weeks after the donation. Exercise should be avoided the day blood is donated, while competitive maximal efforts should be avoided for 6 weeks. Christensen & Christensen [1978] measured athletic performances post-blood donations, reporting a decrease in VO2 Max of -10 to -15%. Most of us do not want to give away 10-15% to our competitors; it's like riding with only half the air pressure in your tyres, making for a long and slow effort at best.
Athletes should have blood haemoglobin and ferritin levels checked prior to donating blood. It is also suggested to avoid both intense impact or prolonged endurance running 5 days prior to the donation and up to 6 weeks post-donation. Noakes [1991] suggests it is safe to donate blood if ferritin levels are above 60 ng/ml and the donating athlete has not run hard for 5 days. He also
suggests NOT giving blood if hemoglobin levels are low, i.e. less than 14.5 g/100ml.
REFERENCES
*** Christensen, T., Christensen, G., The effects of blood loss on the performance of physical exercise, European Journal of Applied Physiology 1978; 39:17-25
*** Noakes, T.D., THE LORE OF RUNNING, Leisure Press, Champaign, Ill. 1991:695.
Article provided by Gary Little from his Program Fitness Newsletter.
Although the article has got a bit of technical content the message is very clear. I competed in the Great Lake Taupo relay a few years back. I started with a leg I had walked previously and started to struggle half way through and ended up going about 2 minutes slower than what I expected for this 8k distance. The second leg was worse with no gas in the tank from the start. I was very disappointed at not preforming well in this team event and I was at a loss for the poor performance until I remembered I had given blood two days previously. Our bodies are normally very good at telling us when we are not 100%. We all know when we have a cold or flu or even when we are tired. Giving blood is different, we normally feel ok soon afterwards and there is no warning our tyres are half flat.
NZ Blood service is super efficient in contacting donors when they are in the area. They normally return on a three month cycle, so if you are preparing for an important event just reschedule for a future visit. I did a club 10k event recently within a week of donating blood and sure enough my time was about 2 minutes slower than normal. Two weeks later my 10k time was still about 1 minute slower.
From your editor:
Reading this article I was a bit ambivalent on publishing this. As a regular blood donor, I realise how essential it is that we do this. Our blood donations are essential for our health service and we, healthy people, can give this gift that saves a lot of lifes. If nobody gave blood, operations would simply be impossible.
At the same time though, it does not make the article less true, and for those of us that are striving for top results, it will be a good idea to plan your blood donations around your events.
And then of course, in principle we publish what you send us.
