First, there’s booking your travel. Then there’s packing and getting to the airport on time. But once you’ve finally made it through security and boarded your flight, being seated on a plane can be a surprisingly stress-free environment where you can try to relax and disconnect from distractions you might have on the ground. But whether you’re planning on diving into a new book, watching a movie, or getting in a quick nap while you’re up in the air, flight attendants warn that there’s one thing you should always make sure to do after takeoff. Read on to see what experts say is a midair must.
Settling in for a long flight usually means getting comfortable and making sure you have anything you may need close at hand. But according to experts in the industry, what you may need most is access to plenty of water or a drink that will keep you hydrated during your trip.
“As a flight attendant, the medical staff tells us we have to drink one liter of water for every four hours of flying,” an Air France crew member told travel money specialist Equals, according to The Sun. “I would definitely tell passengers to drink lots of water.”
It may seem strange that sitting in place for so long would require consuming liquids as if you were working out. But according to experts, the environment onboard your flight can quickly dry you out over the course of your trip.
“Dehydration is a major issue when traveling by airplane,” Yasmin Badiani, a physiotherapist, told Marie Claire. ‘The problem arises due to spending long periods of time in a climate-controlled environment where the relative humidity can be as low as 10-15 percent, which is three times drier than the Sahara desert!”
All of that drying out can significantly add up on long-haul trips. “In an average 10-hour flight, men can lose approximately two liters of water and women around 1.6 liters. This means that on a London to Sydney flight, a passenger could lose up to four liters and eight percent of their bodily water.”
Fortunately, staying hydrated up in the sky doesn’t involve anything more than planning out how much you’ll need during your trip. According to the Aerospace Medical Association, passengers should drink about eight ounces of water every hour you’re in the air, Conde Nast Traveler reports.
Most passengers on shorter flights can easily avoid dehydration, especially if they take advantage of ordering water during beverage service, Peter Hackett, MD, director of the Institute for Altitude Medicine, told the magazine. However, this becomes even more important on flights longer than three or four hours. In this case, you may want to come prepared with your own water bottle you’ve brought from home or purchased in the terminal before boarding.
Still, be careful to space out your hydration throughout your flight. “You should sip water slowly, two to three ounces at a time, throughout the day. If you drink too fast, you risk diluting your blood, which may cause faster excretion of water by the kidneys,” which can cause your body to expel it as urine and slow the hydration process, Leonard Smith, MD, a gastrointestinal, vascular, and general surgeon, told Mel in an interview.
Of course, not all drinks are made equal when it comes to hydration—and water isn’t the only option on those beverage carts. But if you’re choosing to unwind at 35,000 feet with a glass of wine or cocktail, make sure not to overdo it if you’re looking to avoid feeling dried out after your flight. “Alcohol may aggravate dehydration and should be avoided or kept to a minimum,” William L. Sutker, MD, chief of infectious diseases at Baylor University Medical Center in Dallas, tells the website Everyday Health.
But even if you’re sticking to water, you may want to double-check that it came from a sealed bottle before you order it. In a 2019 study conducted by the Hunter College NYC Food Policy Center at the City University of New York, researchers analyzed the drinking water aboard planes on 11 major American airlines and 12 regional airlines. Each was ranked on a scale of five being the best and zero being the worst, with scores above three indicating a relatively clean water supply. Shockingly, results found that seven major airlines scored under a three. Unfortunately, this is also the same water that is often used to make coffee or tea onboard planes.
“Water onboard is regulated under the Environmental Protection Agency to ensure safe drinking water on the aircraft,” the Association of Flight Attendants-CWA (AFA) said in a statement responding to the study. “The [AFA] pushed for this regulation over 15 years ago. The regulation gives broad discretion to airlines on how often they must test the water and flush the tanks. AFA does not believe this regulation goes far enough or is sufficiently enforced.”