The Sleep Whisperer is a series of columns offering insights and advice about sleep health. It is not a substitute for seeking professional medical care.
With summer around the corner, many of us are planning vacations abroad. But before you pack your bags, don’t forget to prepare for jet lag.
Jet lag is more than trouble sleeping. It can lead to daytime fatigue, mood swings, difficulty concentrating, headaches and even digestive problems. These symptoms occur when your internal biological clock is out of sync with the local time at your destination.
The effects can be widespread because our biological clock regulates nearly every system in the body – from the timing of hormone release (such as melatonin for sleep and cortisol for alertness), to variations in metabolism, heart rate and body temperature. This biological clock follows its own internal rhythms and flying across time zones throws it out of whack. Your body does not instantly adjust – it is as though it is still living in your own time zone, while the world around you has moved on.
Are you travelling in Canada this summer? Send us a postcard
We asked where you’re planning to travel within Canada this summer. Here are your best vacation plans
Take, for example, a flight from Toronto to Paris, which is six hours ahead. You land at 10 a.m. local time, but your body still thinks it is 4 a.m. Your brain is flooded with sleep-inducing melatonin, your metabolism is sluggish and your temperature is near its daily low. No wonder you feel groggy, hungry at odd hours, sleepy during the day and wide awake at bedtime.
It is typically easier to adapt to westbound travel. That is because, for most of us, the biological clock tends to run over a period slightly longer than 24 hours (on average 24.18 hours). This creates a natural tendency to drift off slightly later each day, which facilitates adjustments to time zones that are lagging behind. This also makes it harder to drag our biological clock in the opposite direction to match time zones ahead of our internal time.
The good news? After you travel, your biological clock will gradually realign itself to the local time zone using environmental cues. The most powerful of these is ambient light. Other helpful cues include meal timing, physical activity and social interactions. However, realignment takes time – roughly one day per time zone difference if travelling toward the east and two-thirds of a day per time zone if travelling west.
To help your body adapt faster and make the most of your trip, here’s a practical cheat sheet to coping with jet lag.
Getting lots of rest helps your body adjust to new time zones while travelling.The Canadian Press
Before you go
- Get a head start: In the week before departure, begin gradually shifting your wake-up time and bedtime toward those of your destination by 60 minutes each day. This will give more time for your biological clock to adapt.
- Use light strategically: If you are flying east, get plenty of bright light in the early morning and avoid it in the late afternoon and evening. Before a westbound flight, you may want to get some bright light in the two hours before bedtime and minimize your light in the morning. Indoor light is typically not intense enough. Outdoor daylight – even on a cloudy day – is best.
- Sleep well beforehand: Do not start your trip in sleep debt. Being well-rested makes it easier for your body to adjust.
Figuring out when to get some shuteye, and staying well-hydrated, can help during flights.Getty Images/iStockphoto
During the flight
- Say yes to water, no to wine: Environmental conditions in plane cabins tend to be dehydrating. Make sure to drink water but avoid alcohol as it will contribute to further dehydration, and may worsen sleep and thinking skills.
- To sleep or not to sleep? While there are no unified guidelines backed by science about sleep schedules during flights, my advice is: If your flight leaves in the evening and arrives in the daytime at the local time of your destination, try to get some shut eye. If your flight arrives toward the end of the day, staying awake for as long as possible before landing will help build some sleep pressure for bedtime at your destination. Setting your watch to the new time zone may help you better plan your sleep.
- Create a sleep bubble: Sleep masks and earplugs can help create an isolated microenvironment to help you disconnect from the activity around you and fall asleep.
Consider using sleep masks and ear plugs on flights.Reuters
After you arrive
- Resist the urge to nap: If you must, nap early in the day and use an alarm to keep it under 90 minutes to preserve your nighttime sleep drive. Staying up until local bedtime helps you build sleep pressure and counteracts wake signals that your biological clock sends while it is still running at your home time.
- Seek natural light: Spend time outdoors – without sunglasses – to cue your body that it is daytime. If you flew east, prioritize morning light; if west, seek light in the evening.
- Eat light and at local time: Align your meals with local mealtimes. Choose lighter fare since heavy foods may be harder to process while your digestion is still adjusting. While caffeine can help boost your alertness during the day, your sleep system may be more sensitive to it than usual – so limit your intake.
- Move and mingle: Walk, explore and connect with others. Physical activity and social interactions tell your body that it is time to be alert and engaged.
- Consider melatonin: A small dose (0.5-3 mg, non–slow release) of melatonin at bedtime for the few days after landing can signal your body to release its own melatonin at the right time. This can hasten the biological clock’s resetting and improve sleep. Always consult with your health care provider before taking supplements.
- Remember your sleep bubble: When you hit the pillow at the wrong time for your internal body rhythms, your sleep can be more fragile. So just like on the flight, earplugs and an eye mask can help block out distractions and reduce nighttime awakenings.
Dr. Rébecca Robillard, PhD, is a clinical neuropsychologist and associate professor at the School of Psychology at the University of Ottawa. She also leads clinical sleep research at the Royal. Robillard’s main area of work focuses on interactions between mental health, the sleeping brain and the sleeping heart. She co-chairs the Canadian Sleep Research Consortium, a national hub of sleep scientists and clinicians.
