Here are some of the biggest things I’ve learned about Yom Kippur fasting:
Remember to keep your knees bent during long standing prayers. Standing for too long with your knees locked, especially when your body is already weakened from a lack of food and water, could make you pass out. This is actually something I learned in 5th grade choir, but it works for long services as well.
Remember to stand up and sit down slowly during transitions between prayers. No one likes that wobbly, spots-in-the-eyes feeling. Also, if you start getting those spots in your eyes, it’s probably a sign you need water.
If you feel sick, lightheaded, woozy, like you’re gonna pass out, or anything like that, then you need to sit down and at the very least drink some water. When it comes to a choice of either completing the fast or keeping yourself upright, keeping yourself upright always wins. This is a Talmudic ruling! “He who is seized by a ravenous hunger — they feed him, even unclean things, until his eyes are lightened.” (Yoma 83a)
Keep a Nutrigrain bar, or something similar, on hand in case you start feeling really bad. It could be a sign that your blood sugar is off, which means that you need to get some food in your system, even if it’s only a little to tide you over until sundown.
It’s not a competition. You will not be a bad Jew for not finishing the fast. You will not be “less than” the people who do finish the fast. If you feel that it is in your best interests to stop fasting, then stop.
that wobbly, spots-in-the-eyes feeling indicates low blood pressure, and it’s a sign that you need liquids and electrolytes. drinking plain water could exacerbate the problem.
I want to add this:
if you have or have had an eating disorder, you may be worried that fasting during Yom Kippur could contribute to your ED or endanger your recovery. know that you can observe Yom Kippur without fasting. rabbis recognize that for people with eating disorders and other chronic illnesses, fasting is not only not conducive to the point of Yom Kippur, it’s antithetical.
from “Yom Kippur: Should You Fast If You’re Anorexic?”:
On Yom Kippur fasting is used as a tool for temporarily afflicting our souls while we repent, but in the case of someone striving to overcome an eating disorder, using food in this manner is not a good idea. Unlike most people, the 25 hour fast has the potential to bring up hurtful sentiments or even trigger a relapse. Hence, the rabbis concluded that it would be better for such an individual to focus on other aspects of the holiday, such as rituals (like not wearing leather) and the liturgy. One rabbi suggested that by eating regularly and taking extra care of oneself during Yom Kippur, anorexics can perform a unique form of teshuva (repentance) by taking care of the body they once neglected.
in “When Fasting is Not Teshuvah: Yom Kippur with Eating Disorders,” Rabbi Debbie Young-Somers explains:
eating on Yom Kippur is a holy act. Rather than finding “purity” or “spiritual growth” through denying themselves food, the act of eating itself is an act of teshuvah.
she goes on to outline a ceremony of intentional, purposeful eating and prayer with which to observe Yom Kippur.
another suggested prayer here: “Meditation Before Yom Kippur for One Who Cannot Fast.”
take care and be well this holiday.