Giving blood is something we should all try to do if we can – it goes without saying that hospitals don't have access to an endless source of the stuff, emerging from some kind of human tap. In a nutshell: blood is in short supply. BUT donating it can save lives.

Currently, the NHS is urging Black people to donate as there's an increased demand for some rare blood subtypes, such as Ro, which is more commonly seen in those of Black heritage. Plus, the NHS also revealed last year that donors with A negative, A positive or AB negative blood are especially needed, too.

They shared that 69% of donations will treat people with cancer, 17% will help those after surgery, 8% treat diseases, while 6% will provide care for adults and babies in intensive care.

Granted, if you've never given blood before, there's a good chance you'll have a few questions brewing about the process in general. From generic ones like how much blood is actually taken, to more niche queries like can you give blood on your period? or what's the deal with having sex after donating? All relevant, all valid.

So, to answer all your burning wonderings, we asked Ebony Dunkley, a Senior Sister for NHS Blood & Transplant, to share all the information women could possibly need before signing up.

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1. Can you give blood on your period?

"You may give blood during a period, but if you're having a particularly heavy period it would be better for you not to," Dunkley explains. "This is because any form of blood loss can reduce the iron levels in your body and potentially make you feel unwell for a short time. If you are having medical investigations please wait until these have been completed, too."

She adds: "You must also exclude pregnancy if a period has been missed before you give blood. If you have been prescribed medication by your doctor to help cope with period pain or are having heavy or prolonged periods, we ask you to give us a call on 0300 123 23 23 to check this before you make your appointment."

2. How much blood is actually taken?

"During a blood donation, we take 470ml of blood, which is just under a pint."

3. Can all blood types donate?

"All blood types can be taken and we always need different blood groups, but there are times when we may make an appeal for people with rare blood types, such as O negative and B negative, to donate." Dunkley says this is based on the demand for that blood type at a given time.

"If you don’t know your blood type, you will find out after your first donation."

4. How often can you give blood in the UK?

"Women can donate every 16 weeks (so about 3 times a year). Men can give every 12 weeks as they have more haemoglobin in their blood."

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5. Are there tests you have to undergo before donating blood?

When you go for your appointment, Dunkley details that the staff will carry out a pre-assessment to make sure you are able to give blood on the day. She also recommends visiting Blood.co.uk and answering NHS Blood and Transplants interactive questions, as these cover the most common reasons donors are unable to donate when they attend their appointment.

6. Can you find out what happens to your blood?

"Shortly after your donation, you will receive a text message telling you which hospital your blood has been sent to."

7. Do any health conditions rule you out of giving blood?

Although most people can give blood, Dunkley says there are some restrictions - depending on things like your health, medication, and whether you've been abroad recently. Since the pandemic, COVID-19 vaccines have come into play, too. In that how recently you had a jab might affect your ability to donate. So again, it's worth checking before you book your appointment.

Usually, you are able to give blood provided you are: fit and healthy, weigh between 7 stone 12 lbs and 25 stone, or 50kg and 160kg, are aged between 17 and 66, or over 70 and have given blood in the last two years. "If you are underweight, pregnant, receiving IVF treatment, are on certain types of medication or have previously received a blood transfusion, you are unable to give blood."

8. Can giving blood cause you to be anaemic?

"Yes, if you donate too frequently," Dunkley warns. "Haemoglobin (the red pigment in your blood) levels vary from person to person. Men usually have higher levels than women due to women having periods, but we set a fairly high 'cut-off' level because we want to be sure that your haemoglobin will not drop below normal after you have donated."

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9. What should you eat and drink before giving blood?

"Eating regularly before donating will help to keep your blood sugar levels stable. This is important so that you don’t feel lightheaded or dizzy after your donation."

Dunkley advises having a snack before donation, as this can help maintain your blood sugar levels. Ensuring that your diet contains foods rich in iron - such as meats and green leafy vegetables - will also help to keep you feeling well during and after donation.

"It's really important to have plenty of fluid before coming to donate so that you are properly hydrated" she notes.

10. Can you drink alcohol before giving blood?

"We recommend that you do not drink alcohol on the day you have donated. Almost half of the blood that you donate is made up of water. The fluids that you lose during donation can cause a drop in blood pressure which may contribute to you to feeling faint and dizzy. To help prevent this from happening we ask you to drink 500ml of water immediately before you give blood - we’ll give this to you before you donate," Dunkley reassures.

It’s also important to ensure that you are well-hydrated in the days leading up to your donation, she states. This will help to compensate for the fluids lost during donation and will help to bring your blood volume levels back to normal. "It is essential to avoid alcohol before and after donating as this may affect hydration levels and delay recovery."

11. Are you allowed to exercise before/after giving blood?

Dunkley advises to avoid doing any vigorous exercise or heavy lifting on the day of your donation – both before and after you’ve given blood. She stresses that keeping your body in a rested state is important, as it gives it a chance to replenish the fluids lost during donation, which will help you avoid feeling dizzy or lightheaded and keep you well.

"Light exercise such as walking is fine, but please make sure that you are fully recovered and hydrated prior to your donation," she urges.

12. How long does giving blood take?

Not long - Dunkley says that donating blood will take about an hour from your day. Considering women can only really give blood every 16 weeks, what's three hours out of the year to help save multiple lives?

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13. What are the best foods to eat after you’ve given blood?

"You will be encouraged to have at least two drinks and a snack before you leave the donation centre, to rehydrate the fluids you have lost during the donation and to keep your blood sugar levels stable. Once you have left the centre, you are able to eat and drink as normal."

"It’s important to eat a healthy diet with adequate iron in it to replenish the iron you will have lost in the donation," Dunkley adds.

14. Can you have sex after giving blood?

"As stated above, it is strongly advised that you avoid intense exercise for a few hours after giving blood for the same reasons." Noted!

15. Is it fine to go back to work after giving blood?

To help you stay well after you have given blood, Dunkley recommends resting for about 30 mins. She says you are also encouraged to eat and drink before leaving the donation centre.

"But after that, you are fine to go back to work. However, it is best to avoid using the donation arm to carry anything very heavy for the rest of the day. It is also best to avoid having a hot bath or shower after you have given blood."

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16. What physical side effects can people expect to experience afterwards?

"Most people feel absolutely fine after giving blood. Occasionally people may feel faint (lightheaded or dizzy, hot, sweating, trembling, shaky or nauseous) and if you do, you should lie down immediately, rest until you feel better and drink plenty of fluid," Dunkley outlines.

She also reassures that any bruising is usually harmless and will disappear over time. For peace of mind, you will be given "information to advise you of what to do should you have any concerns."

17. Can you give blood if you're a man who sleeps with other men, or a woman who sleeps with other women?

As of June 2021, the rules were changed to make giving blood fairer and now sexuality does not impact whether or not you're able to make a blood donation.

NHS Blood and Transplant has been asking young people for the last few years to make a regular Date2Donate to give blood. To sign up easily to donate and access more information, visit the Date2Donate website.