Nishmat's Women’s Health and HalachaIn memory of Chaya Mirel bat R' Avraham

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Fasting with hyponatremia

18 July, 2017


I am writing regarding fasting on 9th Av.

I am full time nursing a 3 month old. Being thirsty does have an impact of the amount of milk I have available for my baby, however if I were not to have enough milk on 9th Av because I am thirsty, then I could use milk from the freezer that I have expressed already.

However, recently I was hospitalized for very severe hyponatremia (low sodium) and I was very blessed to walk out of the hospital alive. This was the first time it had ever happened and was a big surprise. Since then I have been told to limit my water intake for a period (just finishing after 9th Av) to see if that has an impact. This means I am very thirsty anyway at the moment and if I get too hot, am dizzy, headachy etc.

I really want to fast on 9th Av. In general I have always fasted well but together with feeling physically depleted from the hyponatremia, thirsty in general and needing fluids to nurse and also salty foods, I'm concerned about going about this the best way. How do I go about making sure I do this in a safe way such that I am not whisked to hospital in an ambulance but also that fulfils the important need I have to be part of the Jewish people on 9th Av…?


Please speak with your physician about whether he or she thinks fasting will be safe for you.  If not, you should not fast this year.  At most, you could fast at night.

If yes, you should drink as much as your doctor permits leading into the fast, plan to be in a cool and restful environment during the fast, and be ready to drink or eat immediately should you begin to feel at all dizzy or headachy.

Protecting your health is also a mitzvah.  If you will not be able to fast for health reasons, you can focus your energy on the davening, mourning, and kinot that characterize Tish'ah B'Av.

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