I regularly give blood and have on occasion met other athletes at the donor sessions. Without doubt blood donation is a good thing to do, as we are cycling and running out on the roads we are at greater risk of accident and may one day need to draw on the blood donated by others. We are also healthy individuals ideally suited to supply blood without a significant impact on our own lives, but how will it affect our training and athletic performance? If you have gone through the blood donation process, their risk averse health and safety warnings make you believe you should not even think of moving quickly after donation, but what is the truth? A 1-pint donation of blood reduces blood volume levels by about 10 percent. The loss of fluid has an affect but if you race or exercise in warm weather you will lose more fluid than this and still function relatively normally. Just rehydrate as you would on a warm day. What’s different is you will also lose blood cells. Blood cells will natuarally regenerate, returning blood levels back to normal after about 48 hours. However, the level of blood hemoglobin, your body’s oxygen transport mechanism, typically does not recover fully for up to three to four weeks after donating, so competitive athletes may observe a slight decrease in physical performance during that time period. A 1995 study published in the “American Heart Journal” evaluated 10 male cyclists before and after blood donations to test the effect of blood donation on performance. Each cyclist was measured for oxygen consumption during maximal exercise testing at baseline, two hours before donating, two hours after donating and seven days after donating. Results showed that the maximal performance of the cyclists decreased for at least one week. Submaximal performance, however, was not affected by blood donations. The study concluded that while competitive cyclists should not compete for seven to 10 days after donating, cyclists exercising or training at submaximal intensity may not have negative experiences aside from a higher than normal heart rate the day after exercise. So in summary we will be affected by giving blood, our race performance will suffer for about a week so don’t do it just before an important race. It also tells us we can continue our sub – maximal training, the level most endurance athletes work at 80% of the time, almost immediately after donation. Accepting you may experience an elevated heart rate and some reduction in performance for the following 48 hours. If you give blood already I hope this helps you decide when to resume training and racing after donation and if you don’t it may encourage you to know you can safely include training, racing and giving blood in your athletic lifestyle.