Why does the Red Cross tell me to increase my liquids before I donate blood? I know they think it helps pump up the veins, but doesn’t the extra liquid just make its way out through my kidneys?
Without getting into too much detail on the renal system, osmolarity, dehydration, etc…yes and no.
If everything in your system was perfect, then yes, the extra fluid would, eventually, just go to the urine. However, can you be 100% sure you aren’t a little bit dehydrated? Or that you have enough electrolytes in your system? No, you can’t, so by drinking a lot of a variety of fluids (just water might not be enough) you can ensure you’re healthy enough to lose a liter of blood. Also, if you don’t eben have some water before you donate, that liter of blood has to get replaced with other fluids in your body, intra and extra cellular fluid. This could cause dehydration after donating blood.
So, basically, you’re ensuring that you’ll be OK after giving them your blood.
Unless you take a diuretic it can take a certain amount of time for the kidneys to flush excess fluid so drinking some extra water can make a difference. TheLadyLion has a terrible time with blood draws, hard to locate a vein, and being slightly dehydrated when she is told to drink no water after midnight makes it worse. Last time she went in for a procedure she made sure to drink plenty of water until midnight but the time lag between then and the blood draw made no difference. If you’re just doing a regular blood donation then staying well hydrated is probably not a bad idea.
As long as someone pretty much already answered the scientific part, I will say in my personal experience it makes a difference. I give all the time. There have been a couple of occasions I forgot I was going to donate or donated on the spur of the moment and did not drink more in advance. It took at least twice to three times longer to collect the pint those times I didn’t drink extra fluids versus the times I had remembered.
Well, it didn’t work today. I’ve been drinking 2 or 3 liters of seltzer a day since Tuesday, and they got nothing from my left arm and couldn’t find a vein in my right arm. I don’t feel so bad - two of the three people ahead of me were unable to fill their bags. Must be because it’s getting hot out.
I was told by the nurse where I used to donate that the more hydrated you were:
A) the faster the blood would flow into the bag
B)less chance for dehydration after donating
C) helped prevent severe blood sugar drop
D) and kept post donation blood pressure up to a safe level
I, myself am not a member of the medical arts so I cannot validate theses claims, however, I will say, the one time I did not pump fluids the day I dontated, I passed out 20 minutes after I was done. Oops