Doctors are advising those who typically drink three cups or more of coffee, cola, cocoa or non-herbal tea per day and intend to fast on Yom Kippur to gradually reduce their intake from today to minimize the risk of caffeine-deprivation headaches during the Sunday night-Monday fast. All adults and youngsters who plan to fast should drink more water now to "fill up their tank" and reduce the risk of dehydration and fainting, they add. But people who have an acute or chronic medical problem, take medications or underwent surgery recently, as well as pregnant women, should consult with their personal physicians (and rabbis, if they are observant) before Yom Kippur to learn whether they can fast or not, says Dr. Joe Jamal, CEO of the Terem urgent medical care centers. Those who take drugs for chronic conditions should not stop for the 25-hour fast without consulting their doctors. Diabetics dependent on insulin should not stop the injections and fast, Jamal continues. Cancer patients who are undergoing therapy should not fast without approval from their physicians, as they need lots of liquids to alleviate the side effects of chemotherapy. Jamal recommends that a few days prior to a fast, one should drink at least 10 to 12 cups of water daily. Trying to drink all of this water just before the fast doesn't work as well. because it is difficult to drink a couple of liters of water just hours before the fast, especially if you just ate, and vomiting may result. The body, he says, is better able to distribute the water if it is introduced slowly. According to Hila Boaz, chief clinical dietitian at Netanya's Laniado Medical Center, a number of small meals during the day before the fast is better than one large meal. These meals should be well balanced, including some protein (like eggs and tuna), sources of sugar (like breads and pasta) and some vegetables. Don't snack on junk food. She explains that the last meal on Sunday afternoon should include "slow-release" complex carbohydrates, such as whole-wheat bread, brown rice, pasta, potatoes, couscous, corn, rice and pulses. Salty and spicy foods should be avoided, as these can make you very thirsty soon into the fast. While fasting, says Soroka University Medical Center chief clinical dietitian Adina Ben-Aharon, try to avoid too much physical activity, especially in hot weather. Try to stay in a cool, preferably air-conditioned environment and try to do as little physical activity as possible. Most nursing women can fast without a problem and should continue to nurse as usual. If they stop feeding or pumping milk, they could suffer inflammation and pain. If during the fast your blood pressure or blood sugar falls significantly and you feel very weak and dizzy, you may need to drink and/or eat a small amount and then rest until you feel better, says Ben-Aharon. If you continue to feel very weak or generally ill, seek immediate medical attention, she continues. According to Boaz, the best way to end the fast is to drink a couple of glasses of water or a sugared drink. The first meal of solid food should be a light one. If you are still hungry, wait an hour or two after the light meal. Eating too quickly or too much after a fast can cause abdominal pain and sometimes even vomiting. Magen David Adom reminds the public that on Yom Kippur, an average of 200 children are injured riding bicycles, roller blades, skates and skateboards in near-empty streets. This is five times the usual accident rate for 24 hours. Children should be supervised and wear helmets, as well as knee and elbow protectors. If they go out at night, they must wear light-colored clothing and have reflective tapes on their bikes. Anyone who feels serious weakness or chest pains, who sweats excessively and has difficulty breathing during the fast should call an MDA ambulance immediately, says Natan Kudinsky, chief of training at MDA, which treats an average of 1,500 adults who feel unwell or were injured during Yom Kippur. Dozens of MDA ambulances and mobile intensive care units, with their medics and paramedics, will be added to the usual complement. Since MDA fears hitting children on bikes and skateboards in the streets, its ambulance drivers will drive carefully and more slowly than usual when answering calls, thus more ambulances and medics on motorcycles and motorbikes will be on duty. MDA urges the public to allow rescue vehicles to pass without interference. MDA also stressed taking special care when eating fish during the pre-fast meal. Bones can get stuck easily in the trachea and, when it happens to younger children who do not have a well-developed ability to cough bones up, it can be a grave emergency. Looking ahead, Beterem, the National Center for Child Safety and Health, warns that during Succot, candles should not be lit near flammable succa decorations or wooden walls and should never be left burning without supervision. Make sure that the electric cord for the succa lighting is attached properly and kept out of the reach of young children, Beterem says.