Holiday Jet Lag? The Science of Resetting Your Circadian Rhythm

Your circadian rhythm is your body’s 24-hour timing system—your biological set of instructions that determines when you feel alert, when you get tired, how your metabolism functions, and how your hormones cycle throughout the day.

This internal timing system is regulated by the suprachiasmatic nucleus (SCN)—a cluster of neurons in the brain often called the body’s master clock. It syncs to the environment through cues like light exposure, food intake, temperature, and physical activity.

When you cross time zones, your internal circadian clock is still aligned with your old light–dark cycle, while the external environment around you is suddenly hours ahead or behind. This creates a temporary state of circadian disruption—better known as the symptoms of jet lag.

Common jet lag symptoms include:

• Difficulty sleeping or falling asleep at the wrong time
  

• Excessive daytime sleepiness
  

• Mood changes or irritability
  

• Grogginess, poor concentration, or slower reaction times
  

• Digestive discomfort
  

• Reduced physical performance (noted frequently in sports medicine research)
  
  

Interestingly, jet lag is worse when traveling east. That’s because it’s typically harder to fall asleep earlier than your natural rhythm, and the body adapts more slowly to advancing the clock versus delaying it.

Most people adjust at a rate of about a day per time zone crossed, though it can take a few days—and sometimes a few weeks—to fully resynchronize, especially after long-haul air travel.

Factors that make jet lag worse include:

• Evening arrival times
  

• Excessive nighttime light exposure
  

• Sleep deprivation before travel
  

• Underlying sleep disorders or circadian rhythm sleep disorders
  

• Chronic circadian rhythm disruption from shift work

Fortunately, researchers in sleep medicine, chronobiology, and human circadian rhythms have identified evidence-based tools for treating jet lag and helping the body adapt faster.

Let’s explore some science-backed strategies:

Light is the strongest regulator of the circadian phase—it can induce phase shifts that move your rhythm earlier or later.

• Morning light exposure helps you shift your clock earlier
   → Helpful when traveling east or trying to avoid jet lag by adapting to an earlier bedtime.
  
  

• Evening light delays your rhythm
   → Useful when traveling west or trying to stay awake later in a new time zone.
  
  

To reduce jet lag, follow this general rule:

Seek bright light when you want to be awake; avoid it when you want your body to wind down.

This single habit significantly improves sleep quality, helps you fall asleep at the right time, and aligns your body’s natural rhythms with your local time.

Sleep researchers suggest adjusting your bedtime a few days before flying:

• For eastbound flights: Go to bed earlier each night.
  
  

• For westbound flights: Go to bed later and wake up later.
  
  

Small changes to your sleep wake schedule (even by 30–60 minutes) make transitioning easier once you arrive.

When you're struggling with sleep disruption, circadian misalignment, and poor sleep, targeted nutrients that support deep, restorative rest can be helpful.

Restore by Tally Health is designed to support healthy aging through high-quality sleep, using science-backed ingredients that help you fall asleep faster, sleep more deeply, and wake feeling rejuvenated—making it an ideal companion for holiday travel and circadian recovery.

Taking Restore during the transition to a new sleep wake pattern may help stabilize your rhythm and promote quality sleep while your internal clock adjusts.

Beyond light, your body relies on consistent daily signals:

• Eat breakfast soon after waking
  

• Get bright light exposure
  

• Move your body (even light stretching helps)
  

• Hydrate well after air travel
  
  

These cues strengthen your body’s circadian rhythms, reduce grogginess, and improve alertness.

To avoid accidentally delaying your sleep wake cycle:

• Reduce exposure to bright light at night (especially screens)
  

• Avoid heavy meals close to bedtime
  

• Delay caffeine after crossing time zones
  

• Keep the bedroom cool and dark
  
  

These habits help your circadian clock sync more effectively with your new time zone.

While jet lag recovery is often manageable within a few days, prevention is even better. Research in sleep medicine reviews and sports medicine highlights that you can prevent jet lag or reduce its severity by:

• Gradually shifting your schedule pre-travel

• Using morning or evening light to guide the clock
  

• Maintaining good sleep hygiene
  

• Supporting sleep with science-backed tools like Restore by Tally Health during transitions
  

• Aligning meals and activity with the new local time as soon as possible
  
  

These strategies help your body adapt more efficiently and reduce the risk of sleep problems, sleep disturbance, or extended circadian rhythm disruption.

Holiday travel doesn’t have to leave you battling jet lag disorder, sleep disruption, or excessive daytime sleepiness. By understanding your body’s internal circadian clock and using targeted, evidence-based tools like strategic light exposure, schedule shifting, and high-quality sleep support, you can help your system adjust faster—no matter how many time zones you cross.

With intention—and a little science—you can land feeling aligned, rested, and ready to enjoy the season.