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Should Endurance Athletes give blood?

Do you donate blood? Or perhaps are you considering it? Donated blood saves lives, both in an emergency and for people who need long-term treatment.

As an endurance athlete donating blood, you should be aware of how this will affect you in terms of training. You shouldn’t just simply carry on as normal at your regular training intensity and volume. Giving blood has it’s physical consequences, such as a temporary reduction in endurance performance and sometimes iron deficiency. It is important that you inform your coach that you have donated or that you are planning to donate blood in order for them to plan and modify your training, to keep you as healthy as possible and to understand why your performance ability has decreased.

On average, the body contains 10 pints of blood. When you donate, you will usually donate 1 pint of blood (one unit or 450-500ml). Donating 1/10th of your blood might seem a lot, but it is reported that a car crash victim could need up to 100 pints to survive, so it puts things into perspective!

Once you have given blood, the plasma is the first part of your blood to replenish itself, it takes approximately 24 hours and it is recommended that during this time no strenuous exercise is performed. (If you donate only Plasma, your recovery is much faster.) Next, your platelets restore over 72 hours and finally the red blood cells – it is the red blood cells that carry the oxygen around your body and are important for endurance athletes. It can take four to six weeks for these to fully replenish.

It is the time it takes for the red blood cell recovery that causes your performance to suffer, your work rate is likely to be lower and time to exhaustion is very likely to be much less. A study by Dellweg et al reported a 9% decrease in VO2 Max and 13% reduction in maximal work rate following a 1-unit whole-blood donation. A separate study in 2013 by Hill, Vingren and Burdette found VO2 Max dropped by 15% and time to exhaustion dropped by 19% 2 hours after donation, 7 days later their VO2 Max was still 7% lower. This was tested as a cycling endurance test on a stationary bike.

There is also a significant drop in Hemoglobin, which transfers oxygen from the lungs to the body’s tissues, this means that less oxygen is delivered to the working cells and, when it gets there, its ability to transfer the oxygen from the blood to the cells is also diminished, again reducing VO2 Max.

Donating blood regularly may also affect your iron levels. The body generates hemoglobin from iron stores (ferratin stores) and is a critical for new red blood cell production. Endurance athletes who regularly give blood should therefore consider having their iron (ferratin) levels checked and ensure they get enough iron in their diets.

Judd et all studied how long it takes for an athlete’s performance to return, the study found that performance returned roughly three weeks after donating blood. Whilst this doesn’t seem like too long, it means you have had almost one month of training at a reduced capacity every time you donate, which will almost certainly affect your overall, long term performance gains.

We don’t want you to think that we are trying to put you off donating blood, as cyclists and thrill-seekers who love descending mountains and riding fast, we are all too aware of how important medical facilities and stores of blood are for those that are unfortunate enough to need such serious medical interventions. The purpose of this article is to inform and educate, helping you to plan your blood donations around your key training blocks, so that it won’t negatively affect your A-race.

It is perhaps interesting to observe that there are no big studies or long term research in to whether donating blood more seriously affects the higher-end athletes, whether that’s professionals or the top age group racers in endurance sports. It would be easy to speculate that they might not donate blood because of the performance and training losses in the short term negatively affecting their sporting careers, however I will leave you to draw your own conclusions here.

The off-season is the obvious time for you to donate blood, where you are not pushing yourself to your training or racing limits and you have time to allow your body to replenish and recover. Eat lots of iron-rich foods and aim to leave at least 3 months between your donation and your key races for optimal recovery. If you have any concerns, then get your iron (ferratin) levels checked to ensure you are not deficient.

Giving blood is one of the most important things we can do. If you would like to learn more about how to register to give blood then visit the below website:


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