Fasting close to donating blood (and other questions)

December 26, 2024 1:01 PM

I'm hoping to do a New Year's fast on Dec 31 and Jan 1st, with electrolyte drinks permitted. I'll return to eating normally Jan 2nd. I have a blood donation appointment on Jan 3rd. Is this a bad idea? I also have a couple other questions about blood donation below.

I've donated blood four times so far. The first was in 2020. I wasn't very healthy then - poor diet, little exercise, lots of stress. They had to stop the donation because either they couldn't get enough blood or it took too long - I can't remember. I didn't suffer any ill effects, though.

Since then, I've vastly improved my diet, exercise routine, and overall health. I've donated three times this year, three months apart, and I've been able to complete all of them. I do seem to have slow flowing blood, though.

I'm very prone to dehydration and electrolyte imbalances. I've not always eaten very well before donations as I'm not a huge breakfast person and my local centre closes early, but I do prioritize hydration and salt. I haven't had any issues post donation except shortness of breath and easier fatigue when doing things like heavy lifting or climbing stairs for a few days.

I'd really like to be able to do this fast, as it's a tradition for me, and to keep this appointment, as I have a few friends coming with me. If people think it's a terrible idea, though, I won't. I'm wondering, though, if people have any suggestions for how I can do both and make sure I'm able to donate. My biggest fear is wasting resources because they can't get enough blood out of me. I'm open to switching to a gentler liquid fast (juice and broth, maybe)?

I'm also wondering about exercise beforehand - what are people's experiences? I've looked it up and seen all kinds of different recommendations as to how much exercise is ok and how soon beforehand.

posted by wheatlets to Health & Fitness (4 answers total)

I was a frequent donor (whole blood and platelets) for 15 years up to 2021. The only advice I ever received was to hydrate well for the 3-4 days prior. Drink more water than you think you need. And the only times I had issues (apart from anemia) were because I didn't make an effort to hydrate. I can't find different advice either locally or from the Red Cross, but I'm not an expert. There were a bunch of times I'd run/rode my bike the morning of an afternoon donation, and didn't have issues.
posted by Gorgik at 1:41 PM on December 26

Your hydration is really key to having an easy stick and getting done within the safe amount of time. Can you fast on the 30th and 31st instead? That gives you two whole days of a regular diet before your donation. I used to do only one day of extra hydration and was told 3 is better. In my experience, exercise before the donation is not a problem. It is after where you need to rest. But too much exercise after a two day fast could also be a problem. Another risk of exercise too soon before the donation is that your blood pressure or temperature reads too high, and they reject you.
posted by soelo at 2:00 PM on December 26

I'm a big exerciser + a blood donor. I find that exercise beforehand is irrelevant -- whether I do or don't, the donation and recovery are no different. I think it's the same for food intake, so I'd guess your fast isn't any big deal. However I do prioritize hydration, and go hard on that.

In terms of slow donations, are you switching arms? I absolutely have a slow arm and a fast arm. No idea why, but now that I know that, I always donate from the fast arm.
posted by BlahLaLa at 2:03 PM on December 26

I'm a doctor.

Stay hydrated. Eat complex carbohydrates on the intervening day. You'll be absolutely fine.
posted by BadgerDoctor at 3:05 PM on December 26 [4 favorites]