As the moon rises over North America, the holy month of Ramadan begins.
But the intense heat and dry conditions will make this year's fast even more challenging than usual when Ramadan falls in the middle of the Northern Hemisphere's summer.
Personal trainers and physicians say it is challenging, but possible, to stay hydrated in the long hours from sunup to sundown.
"Dehydration is a very big concern," said Mubarakah Ibrahim, a personal trainer and founder of FitMuslimah.com, a fitness site for Muslim women. "You're going to go 16 hours without eating or drinking anything and most people don't drink enough anyway."
Going without water during a hot July day can be dangerous, but Ibrahim advised against overcompensating by waking up in the middle of the night and chugging several bottles of water. The body can't absorb it quickly enough, she said.
Instead, she suggests drinking 10 ounces every half-hour or so throughout the evening.
"Create a plan, literally write down how much water you're going to drink and when," Ibrahim said. She recommends people drink half their body weight in ounces of water each day.
After a long day of fasting the temptation might be to fill up on sweet or greasy foods, but Ibrahim said nutrient-rich foods such as collard greens, kale, broccoli and other vegetables are all better choices when breaking the fast.
"People think we would lose weight during Ramadan, but actually we usually gain weight because by the end of the fast you're so hungry that you're eating things you normally wouldn't touch," she said. "You just eat everything in your path. Do not stand in between a fasting Muslim and a plate."
But, Ibrahim said, for a healthier fast it's important to resist that temptation and eat healthy first.
"When you do eat, your food has to be fuel and you have to get all of your nutrients whenever you can," she said, adding an early morning protein shake can keep you full hours longer than a doughnut or sugary cereal.
Ibrahim also suggested taking a multivitamin daily to supplement the nutrients observers may miss out on during Ramadan.
This year is the first time in more than 30 years Ramadan has started in mid-July. Like other faiths, Islam follows the lunar calendar, meaning Ramadan falls about 11 days earlier each year.
The first day of fasting began Friday in Mecca, Saudi Arabia, home to Islam's holiest shrine.
In North America, mosques usually wait for the moon to be sighted locally before announcing the beginning of Ramadan, which will happen either tonight or Friday night.
Getting enough sleep is also a challenge, since observers wake up in the wee hours for a meal before sunrise and stay up for congregational prayers after 10 p.m. each night at area mosques.
Dr. Mohammed Sahloul, a member of the Mosque Foundation of Bridgeview and chairman of the Council of Islamic Organizations of Greater Chicago, said people with chronic diseases need to discuss fasting with their doctor ahead of time to make a plan for medication and staying healthy.
People who are pregnant, traveling, sick, too young or too elderly to fast are exempt.
People whose work involves extreme exertion also may make up fasts at a later time. Muslim athletes competing in the Summer Olympics may not be fasting right now, given the intensity of their workouts and the fact they are traveling to London.
The body gets used to the fasting routine fairly quickly, Sahloul said, but what's really difficult for many is the withdrawal symptoms of not having coffee, soda or other sugary drinks throughout the day.
He said it is best if Muslims start weaning themselves off caffeine a few days before Ramadan begins and even take a small pain killer before sunrise to cut off a headache at the source.
"One of the benefits of fasting is to have better control of your body, so if you have addictions, it's the best time to get rid of those as well," he said.
The summer dates of Ramadan may actually be easier on students because they don't have to worry about having enough energy for school, gym classes or studying.
Anisha Ismail Patel, a mother of three in Arlington Heights, said she and her oldest daughter will take time this month to read the entire Quran.
Patel will also be busy as executive director of the Muslim Women's Alliance. She has helped organize 14 different events throughout Chicago and the suburbs for the month of Ramadan, including preparing food baskets for needy families and helping at homeless shelters.
"Charity is a pillar of Islam and it's really important that we take care of our neighbors in need whether they're Muslim or not," Patel said.
Patel's children are too young to fast during all of Ramadan, but charity work is a way for them to mark the holy month and give back.
"Ramadan is a really exciting time of giving and reflection," Patel said. "Life gets hectic with kids and family, but during Ramadan you're really conscious of your prayer times, improving yourself, bettering yourself."
It's also becoming trendier for young Muslims to use the month as a time to refresh and rid themselves of bad habits, such as devoting too much time to watching TV or the Internet, eating healthier and spending more time with family, Sahloul said.
"It's a time to really change your lifestyle and think of how to improve yourself, to recharge your spiritual battery so to speak," he said. "During the year, we don't have a lot of time to reflect on that, but Ramadan gives us that chance."