This article originally appeared on TravelAndLeisure.com.
There are all sorts of things you probably should pack in your carry-on (another pair of underwear, toothbrush and toothpaste, a book), but there's one thing you'll never want to forget: a tennis ball.
Stick with me, here. It's not so you can spend your flight bouncing your tennis ball against the airplane cabin wall (really, don't do that). Instead, use it to help out with some mid-flight stretching.
We all know sitting for an extended amount of time wreaks havoc on your health, so it's no surprise that long-haul flights are not high on the list of healthy activities. Getting up, walking around, and stretching are going to help keep you comfortable and make battling that jet lag just a little easier on the muscles.
Ali Gjoz, a surgeon from the London Orthopaedic Clinic shared a few tips with the Daily Star. "Taking a tennis ball or a massager on the plane will help increase circulation," he says. Roll it over your shoulders, lower back, legs, and the bottoms of your feet to help get your blood flowing again.
If you just can't fit that tennis ball in your bag (no shame—craming a week's worth of outfits into a carry-on is sometimes necessary), Gjoz suggest massaging your legs, starting with the ankles and moving up, to help get the blood moving back toward your heart.
And if you're worried about what your fellow fliers will say, don't be. In-flight masking will still grab more stares that stretching and massaging with a tennis ball.