Travelling to another time zone can disrupt your internal clock and take a toll on how you feel. The Garmin Jet Lag Adviser offers personalised insights to help you stay on track, with tips designed to minimise the effects of jet lag and ease your transition to local time when appropriate. You'll be supported by science-based guidance on when to seek or avoid light and how to plan sleep and exercise. The guidance is backed by additional insights on nutrition, naps and caffeine intake for easier travel.
Simply add your trip to your calendar to get tailored insights for the days before your trip, during your trip and after you return home.
What is jet lag?
Jet lag is a circadian rhythm condition triggered by rapid travel to another time zone. While crossing one or two time zones can be disruptive, the effects of shorter trips are generally mild and can be overcome with minimal effort. When crossing three or more time zones, the likelihood of common jet lag symptoms increases significantly.
Common jet lag symptoms include trouble falling asleep and staying asleep, daytime sleepiness, reduced mental and physical energy, digestive problems and general malaise. The Jet Lag Adviser predicts your risk of symptoms (mild, moderate, significant or severe) based on the number of time zones crossed and the direction of travel.
Circadian rhythms
Your body's internal clock follows a circadian rhythm pattern, a personal cycle of physical, mental and behavioural changes that occur over a roughly 24-hour period. The suprachiasmatic nucleus of the hypothalamus is the main circadian rhythm pacemaker. It generates a circadian rhythm that affects the activity of virtually every cell, tissue and organ in your body. Environmental light and darkness help guide and tune your natural rhythm. Physical activity, meal timing and daily routines act as additional cues that help you stay aligned. Deliberately changing the timing of these elements can help minimise jet lag symptoms and, when needed, optimise your transition to local time.
Your usual circadian rhythm can be recognised from your sleep history. The Jet Lag Adviser provides feedback based on the alignment, or misalignment, between your biological clock and the normal waking hours of your current time zone. You can also track your biological clock shifting towards local time. Once you are fully aligned with local time, your status will be updated to “Adapted”.
Strategies to reduce jet lag and adapt optimally
The length of your stay in your new location determines whether you should prioritise adjusting your internal clock to local time or simply work to minimise the effects of jet lag. Actively shifting your internal clock is recommended only for trips lasting more than 72 hours.
Seeking light and avoiding light
Deliberately timed exposure to bright light is the most effective strategy for shifting your internal clock. Light entering your eyes during your normal circadian cycle is the main synchroniser of your circadian rhythm. Sunlight has a strong effect on your body and is generally preferred, but it isn't always available. When the sun isn't shining, you can get the same result using a light therapy lamp. Leaving the lights on indoors and setting your phone and laptop screens to full brightness can also help.
Avoiding light at certain times can be effective too. When light avoidance is recommended, try keeping the lights off indoors, avoiding electronic device screens and wearing sunglasses if you need to be outside during the day. Consider wearing an eye mask when sleeping, especially if the sun is still up when you go to bed.
Sleep schedule
Ideally, you should match your sleep schedule to local time as quickly as possible, especially if you plan to shift your internal clock to local time. Small changes to your sleep schedule before your flight can give you a head start on matching normal sleep and wake times at your destination. Good sleep is especially important before a trip, as fatigue accentuates many of the symptoms associated with jet lag.
Physical activity and exercise
Physical activity and exercise affect your circadian rhythm by reinforcing the signal that it's time to be awake and alert. Evening exercise helps you stay awake longer, while morning exercise boosts the waking process. General activity during the day helps you stay energised, reducing jet lag symptoms and sleepiness, and helps you sleep better at night. Any exercise can be beneficial, but exercising outdoors when light exposure is also recommended is an especially powerful combination.
Travelling east vs travelling west
Travelling west makes your day longer, extending the time between waking up and going to bed in your new location compared to usual. Going east reverses the situation; the locals head to bed at what may feel like afternoon to you. The Jet Lag Adviser takes the differences between eastward and westward travel into account when estimating the potential for jet lag and the typical rate of adaptation.
Experienced travellers often notice that heading west is usually less disruptive than travelling east. Science has an interesting explanation for this. How quickly your biological clock syncs with local time is influenced by an interesting fact about circadian rhythms. There are 24 hours in a day, but the typical circadian rhythm is slightly longer. Your body uses cues from its environment – such as light/dark and daily schedule – to keep you tuned to a 24-hour day. It's simply easier for your biological clock to lengthen its day than to shorten it.
As a result, your internal clock adapts faster when you go west and more slowly when you travel east.
For example, when travelling from Los Angeles to London, the chance of experiencing jet lag is high, as London is eight time zones ahead of Los Angeles. An LA resident travelling to London can typically expect it to take a little over a week for their biological clock to fully sync with Big Ben. After fully adapting to London time, however, the effects of the return trip may fade in as little as 5 days.
Although the effects of jet lag can't be avoided entirely, by following the Jet Lag Adviser's guidance and properly managing light, sleep and exercise, you can get a big head start on enjoying your next trip and boosting your productivity.
