🕐 What Is Jetlag?
Jetlag (desynchronosis) is a circadian rhythm disorder that occurs after rapidly crossing multiple time zones. The body's internal biological clock (circadian rhythm) no longer aligns with the external time of day, causing sleep disturbances, fatigue, digestive problems, reduced concentration and — most importantly for athletes — significantly worsened physical performance until the body adapts.
🧬 Physiological Effects on Sport
😴 Sleep Disturbances
Difficulty falling asleep, early awakening, reduced sleep quality. Sleep deprivation directly reduces strength, endurance, and reaction time.
🌡️ Body Temperature Rhythm
Body temperature rises and falls according to the circadian rhythm. A mismatch with competition time means that an athlete may compete when their body temperature and performance curve is at its lowest point.
💪 Muscle Function
Maximum muscle strength and power are reached in the early evening (18-20 h) according to the internal clock. Jetlag shifts this peak, and the athlete may compete during their “minimum.”
🧠 Cognitive Function
Reduced concentration, slower reaction time, worse decision-making. Especially critical for technical and team sports.
📊 Traveling East vs. West
| Direction | Adaptation Difficulty | Effect | Strategy |
|---|---|---|---|
| Eastward (phase advance) | Harder adaptation — ~1 day per time zone | Effect similar to sleep deprivation. Evening competitions become “nighttime” according to the internal clock | Start adaptation before travel: go to bed 1-2 hours earlier, get more light in the morning |
| Westward (phase delay) | Easier adaptation — ~0.5-0.7 days per time zone | A more natural adaptation, as the circadian cycle naturally tends to lengthen (>24 h) | Start adaptation before travel: go to bed later, get more light in the evening |
📋 Adaptation Strategies
- Light management (most important strategy): Light is the main synchronizer of the circadian rhythm. Morning light advances the rhythm (makes it earlier), evening light delays it (makes it later). Use it strategically: eastward — morning light, westward — evening light.
- Gradual adaptation before travel: Start changing sleep and meal times by 1-2 hours per day, 3-4 days before travel.
- Melatonin: 2-5 mg before sleep (local time) can speed up adaptation by 1-2 days. Use only for the first 3-4 days after arrival.
- Hydration and nutrition during the flight: Drink plenty of water, avoid alcohol and caffeine. Eat lightly, avoid fatty foods.
🎯 When to Arrive Before Competition?
General recommendation: arrive at least 1 day earlier for each time zone crossed. In practice, this means: for a 1-3 h difference — 2-3 days; 4-6 h — 4-7 days; 7-9 h — 7-10 days; 10-12 h — 10-14 days. If time is insufficient, strategy no. 2: arrive just 1 day before and plan the competition according to your home time (i.e., if the competition would be in the evening in your time, but in the morning local time, you will still compete according to your peak).
🙋 Frequently Asked Questions
Yes! Understanding time zone adaptation helps you train more effectively, avoid injuries, and achieve better results even at the amateur level.
We recommend PubMed, Google Scholar, and Sports Medicine journals. It is also worth following publications from the Lithuanian Sports University.
It depends on the specific study. Some methods require laboratory equipment, while others can be performed with portable devices.
Coaches who understand time zone adaptation can individualize training programs, monitor progress, and adjust loads in a timely manner.
📚 Additional Resources and Sources
To deepen your knowledge about time zone adaptation, we recommend:
- Scientific publications and conferences of the Lithuanian Sports University (LSU)
- International journals: Journal of Sports Sciences, Medicine and Science in Sports and Exercise
- Annual congresses of the European College of Sport Science (ECSS)
- Sports science podcasts: Science of Sport, The Real Science of Sport
- Sports science programs of the Lithuanian National Olympic Committee (LTOK)
⚡ Pro Tip
Sports science is constantly evolving. What was considered true 10 years ago may be refuted today by new research. Be curious, read the latest literature, and don't be afraid to experiment — of course, while following safety principles.