Summer travel is in full swing — as is the grog and fatigue of jet lag.

Traveling across time zones disrupts our circadian rhythms, resulting in exhaustion, sleep woes, moodiness and digestive troubles.

Why do the travel gods punish us so?

Nearly every cell in the human body operates on a circadian clock, an internally driven 24-hour rhythm. Recalibrated by different factors, these clocks reset every day.

Our circadian clock functions best when we stick to routines and schedules that support it — sleeping, waking and eating at the same time every day.

Long-haul travel upsets those regimens, confusing the body and leaving us jet-lagged.

While some degree of jet lag may be impossible to avoid, three sleep experts gave Time magazine several suggestions this week for how to minimize the effects.

Shift your bedtime

Travelers facing a time change can prepare their bodies before takeoff by adjusting their sleep schedules, said Dr. Sairam Parthasarathy, director of the Center for Sleep, Circadian, and Neuroscience Research at the University of Arizona Health Sciences.

“Starting about three days before traveling east, move up your bedtime by 30 minutes each night,” he explained. “Going to bed progressively earlier will prime your body to start getting tired at a normal bedtime in New York, even though it’s early back in California.”

Those traveling west should follow those instructions in reverse.

“Go to bed progressively later over the days before your flight, and once you land, try to get some light exposure in the afternoon and evening to delay sleep,” Parthasarathy told Time.

Traveling west tends to make the sleep adjustment smoother, he added, as it’s easier for people to delay sleep when they’re tired rather than forcing slumber when they’re not.

He maintains that a small dose of melatonin can help ease you into shut-eye when your body is fighting it.

Make the most of your first day

What you do when you land may matter more than prep before your flight.

Dr. Alon Avidan, director of the University of California Los Angeles Sleep Disorders Center, tells Time that light exposure is the key regulator of circadian rhythms.

He advises travelers who land in the morning to wear sunglasses to avoid seeing direct sunlight until early afternoon. As your trip progresses, it becomes more OK to see morning light.

Biohackers, meanwhile, maintain that the best way to combat jet lag in a new location is with a barefoot walk in the dirt.

Known as “earthing” or “grounding,” devotees claim you can rejuvenate your body by connecting it to the negative electrical charge that flows through the earth.

Avoid naps

A midday nap is a serious no-go for travelers hoping to stave off symptoms of jet lag.

Avidan explains that an afternoon snooze “only prolongs the mismatch between your internal time and the external time. If you absolutely need some shut-eye to get through the day, take a strategic power nap of no longer than 20 minutes, ideally no later than 2 p.m.”

If you sleep any longer or later, you risk compromising your overnight sleep. The same timeframe applies to consuming caffeine.

Adjust your eating

In addition to sunlight exposure, food intake plays a critical role in regulating circadian rhythms.

Research suggests that having a hearty breakfast when you reach your destination can help your body adjust to a new time zone.

While you’re on your way there, however, experts caution against eating at intervals that are at odds with the time zone you’re landing in. Eating an airplane dinner in the wee hours of the morning will confuse your brain and contribute to jet lag.

If you can hold out until you reach your destination and sit down at a normal mealtime, your body and brain will thank you.

Limit in-flight booze

A study published last month found in-flight cocktails can be dangerous for the heart.

Avidan told Time that drinking alcohol disrupts sleep, causing imbibers to wake up when their blood alcohol levels dip.

For this reason, he urges travelers to lay off the sauce when flying, no matter how tempting the promise of a celebratory cocktail or complimentary glass of wine may be.

Get moving

Emily Schmitt — who runs the Circadian Rhythm and Exercise Research Lab at the University of Wyoming — tells Time that travelers should resist the call of the hotel bed and a room-service breakfast on their first morning in a new time zone.

Instead, opt to get up and get after it with 20 minutes of physical activity.

“It doesn’t have to be an all-out sprint or a hard CrossFit workout. It could simply be wandering down to your local coffee shop,” Schmitt said.

Exercise, even low-key movement, supports healthy digestion, acclimation and the battle against jet lag by keeping you alert until it’s time for sleep.

Tread lightly with sleeping pills

Many travelers turn to sleeping pills on long-haul flights to try to get as much rest as possible.

However, the choice to medicate for slumber is a dicey one, as mixing meds with travel-induced exhaustion can lead to disorientation, confusion and fatigue upon waking or landing.

If you choose to go the pill route, proceed with caution, particularly if the medication is not one you use regularly.