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Fasting on Yom Kippur may damage my body


I always fast on Yom Kippur, but I’m not sure what to do this year. I’ve recently been diagnosed with stage 2 chronic kidney disease. I’m told that it may have been caused by elevated blood calcium which damages the kidneys. I may have to have surgery to remove the parathyroid gland which regulates calcium levels in the body. I know that drinking fluids, and maintaining adequate hydration is important to protect the kidneys and I am concerned about permanent damage I could be causing to my kidneys by not drinking on Yom Kippur. Please advise me what I should do.


Due to your medical condition you should drink “shiuruim”, meaning that you should drink less than 40cc of liquid, and then wait 9 minutes, and then you can drink again, wait nine minutes… This way you will be able to hydrate your body. It is technically possible to drink a liter and a half in this fashion. Since your condition can be life threatening, you are allowed to drink as much as you need to make sure you are not going to be putting yourself in danger. It would be a good thing to find out from a doctor how much you need to drink. You shouold also be careful not to do thinks that will cause you to need more hydration, as you don’t want to cause yourself to have to drink any more than what you need.

 May you be blessed with a gmar chasima tova, a good healthy year, to you and your whole family, and have an easy, safe fast.  



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  1. Thank you! I’m so grateful for your compassionate reply.
    1. I will drink the shiurim as directed. Normally, because I’m more thirsty than in the past, drink as needed to quench my thirst, and make sure that my urine stays light.
    2. I have a question about your question asking me to ask a Dr. about how much fluid I need. Did you mean that I should find out how much one should drink daily, or did you mean how much would I need for my specific health problem? If the former I think it’s 1-1.5 L. As for the latter, it would be difficult to answer. I have been told that calcium is toxic to the body, and that the body has a hard time excreting excess calcium. (Women who were taking calcium for their bones were found to have more strokes and heart attacks and have been advised now to get their calcium from food only)
    I assume that the damage from elevated calcium is gradual, and depends on how high it is on particular days. And I hope that drinking water dilutes calcium levels in the blood and hopefully would be less damaging.
    Would it be reasonable to drink until the urine is light?

    1. The reason I said that you need to speak to your Dr. is because essentially each time that a person eats or drinks on Yom Kippur he is transgressing the commandment to refrain from eating or drinking on Yom Kippur. Of course the mitzvah of protecting our lives supersedes the commandment to fast. In fact even if there is doubt that the person is in a life threatening situation permits him to eat or drink. However there are some people that may need to drink only a little bit in order not to be in a life threatening situation. Therefore the exact amount that YOU need to drink is really dependant on what your doctor says is needed for you.

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