From blood pressure to iron levels—here’s the science behind your donation.
Have you ever wondered how blood donation affects your health? Some benefits of donating blood regularly include giving your heart a healthy ‘work out’, stimulating the production of blood cells in the bone marrow, doing a quick health-screen by checking your blood pressure, pulse, haemoglobin and ferritin levels in our clinics, and gaining a mental health boost from helping three strangers.
How Long Does It Take My Body to Recover the Lost Blood After Donating?
Your blood is made up of different components, each taking varying amounts of time to recover. You should be able to replace the fluid lost within 24-48 hours, provided you rehydrate well, and platelet cells typically recover within a few days. Red blood cells which carry oxygen take much longer (4-8 weeks) to regenerate in the bone marrow, and the iron lost during donation takes 6-8 weeks to be replenished. For this reason, we strongly advise blood donors to use the iron replacement tablets we offer after each donation to help restore their iron stores. We also limit whole blood donations to once every two months to prevent overstraining our donors’ iron reserves.
How Will I Feel After Donating Blood?
Each person reacts differently to the donation process, but most will feel okay, especially if they drink enough fluids before and after donating. Some people may feel light-headed, dizzy, or even faint after giving blood. Our staff are highly trained to support our donors and know exactly what to do to assist you. We also recommend that you relax in the chair after your donation, have a drink and a snack, and fully recover before leaving the clinic. Other helpful tips to improve your donation experience include having a salty snack half an hour before donating to help boost your blood pressure and doing the leg and buttock muscle exercises we demonstrate while lying on the donation bed.
Can Donating Blood Reduce Blood Pressure?
Some studies suggest that donating blood may lower blood pressure, but we firmly advise against using blood donation as a method to control hypertension. Donating blood when your blood pressure is extremely high could put you at risk of having a stroke or other complications. At WCBS, we allow blood donation if your blood pressure is no higher than 180/100 and no lower than 90/60. Individuals with very low blood pressure are also advised against donating, as losing blood could further lower their blood pressure and raise their chance of fainting.
Can Donating Blood Cause Anaemia?
Yes, unfortunately, it can happen if you donate blood regularly. Anaemia is diagnosed when someone has a low haemoglobin level. Haemoglobin is the remarkable protein inside a red blood cell that allows it to carry oxygen throughout the body. We check your haemoglobin level using a finger-prick blood test before you donate, and the level must be above 12.5 g/dl for women and 13.5 g/dl for men. If your haemoglobin level is too low, it indicates that you do not have enough red blood cells to safely donate to others. While we aim to collect as much blood as possible, we cannot compromise your health in the process.
Can Donating Blood Cause Weight Loss?
Sadly, no, because this would be a brilliant way to attract donors! While your body burns calories to replace the blood lost during your donation, donating blood does not impact your baseline weight and fat stores. At WCBS, all blood donors must weigh 50kg or more (55kg for plasma donors) to ensure they can tolerate the loss of 450ml of blood during their donation.
Can Donating Blood Reduce Cholesterol?
Surprisingly, it can, to a small degree, although the mechanism is quite complicated and is related to the loss of iron during blood donation. We can sometimes see if a donor with very high cholesterol or triglyceride levels donates blood because the colour of their plasma (the liquid part of the blood) appears milky. Donors with high cholesterol levels should avoid consuming a high-fat meal before donating, as this can increase the fat content in their blood, making it difficult for our laboratory to test their blood.
Can Donating Blood Affect Your Period?
No, it doesn’t. Some people believe that you cannot donate blood while menstruating, but that is not true. If you pass the haemoglobin screening test and are feeling well, you are welcome to donate blood. Since women menstruate monthly and lose iron through this process, the haemoglobin threshold for women is lower than for men. Women are also more susceptible to iron deficiency because of their regular blood loss.
Donating blood is managed with your health in mind, from the checks we do before you donate to the recovery advice we give afterwards. In return, you leave knowing that one simple act has the power to safeguard the lives of others.
