- Can runners donate blood? Will it affect my performance? – Anonymous
- How long will i take to completely recover and run again, if i had donated blood? – Anonymous
MOK YING REN – Every hour, the hospitals in Singapore require 14 units of blood to save lives (one unit is equivalent to about 450ml). As a surgeon-in-training, I have seen how easily blood is lost – patients bleeding from wounds, in their internal organs, and even through long and complicated surgeries. Unfortunately, the national blood supply is not as easily replenished.
Why is blood so important?
Purpose of Blood
Blood delivers oxygen from our lungs to all other parts of our bodies. Our red blood cells contain a key protein – haemoglobin (Hb). Oxygen cells in our lungs bind to Hb in red blood cells, and are transported to body cells for metabolism.
During metabolism, oxygen reacts with glucose and other chemicals obtained from food to produce energy. This also helps cells to grow and reproduce, and stay healthy.
Carbon dioxide produced during metabolism is then carried back to our lungs by blood, where it is exhaled.
Impact of Blood Donation
Our body holds about 5 litres of blood. For every blood donation, 1 unit (or 450ml) of blood is withdrawn.
According to a 2016 meta-analysis published in the Journal of Blood Transfusion, the Hb concentration in our bodies is reduced by 7% after making a blood donation. The Hb concentration in our bodies then gradually returns to normal over the next 2 weeks.
This is expected, but how exactly does this impact your performance as a runner?
Effect of Blood Donation on Performance
A reduced Hb concentration will result in lower oxygen carrying capacity. There is no doubt that your running prowess will be affected.
In 1995, a study published in the American Heart Journal evaluated 10 male cyclists before and after donating blood to test the effect of blood donations on exercise performance. Results showed a decrease in the maximal performance of all the cyclists for at least a week.
More recently, in 2016, a randomised controlled trial published in the Sports Medicine Journal found that maximal power output, peak oxygen consumption and Hb mass all decreased for up to 4 weeks after making the blood donation.
Interestingly, both studies found that the submaximal performance of their test subjects was not affected. Therefore if you are a recreational athlete exercising at submaximal intensity, you should not have any negative experiences other than a higher than usual heart rate.
Recovering from a Blood Donation
To recover faster after a blood donation, you may consider taking iron supplements.
A randomised controlled trial was conducted to investigate the effectiveness of iron supplements post-blood donation. The results were published in the highly-regarded Journal of American Medical Association (JAMA) in 2015 – it was found that with iron supplementation, Hb recovery time was halved from a mean of 78 days to 31 days.
More drastically, for people who usually have low iron levels, their Hb recovery time dropped from a mean of 158 days to just 32 days!
Making a Blood Donation
As you can see, your running performance is not necessarily a barrier to donating blood.
If you are a competitive runner aspiring to set personal records, I would still encourage you to make a blood donation. You can plan your blood donation based on your running calendar. For example, you can do it right after a major marathon, as you would need down-time to recover from your race anyway! Once you are physically ready to get back into training, your Hb levels should be ready too!
However, if you any reservations about blood donation, an alternative would be to make a plasma donation, which will not affect your Hb levels at all.
You can run and donate blood. Let’s give our precious blood to someone who may need it for survival today.