When you cross many time zones, cues such as light exposure and mealtimes are disrupted, putting your internal clock and the external cues your body receives out of sync.
By Tania Moffat
Ever feel you need a vacation to get over your vacation? Jet lag is a real problem for travellers and can last for several days, depending on your body and the direction and distance you have travelled.
Today jet lag is considered a temporary sleep disorder, but for years it was written off as just a state of mind. Studies have now shown that the condition actually results from an imbalance in the circadian rhythms (physical, mental and behavioural) that regulate our body’s natural or “biological” clock. These rhythms control sleeping and waking, the rise and fall of our body temperature, the plasma levels of certain hormones, hunger, mood and other biological conditions that are affected largely by our exposure to sunlight.
Symptoms come later
Any time you travel quickly between two or more time zones, as you do when you travel by air, your body’s circadian rhythms are affected. Essentially, your body’s biological clock becomes stuck on its original schedule, causing you to experience symptoms such as daytime fatigue, disturbed sleep, difficulty concentrating at your normal level, gastrointestinal problems, mood changes and a general feeling of being unwell. Symptoms usually present themselves within a day or two of arrival. When you cross multiple time zones, cues such as light exposure, mealtimes and social engagements are disrupted, causing a de-synchronization between your internal clock and the external cues your body is receiving.
The more time zones you cross, the more intense the symptoms you may experience. While the symptoms are temporary, they can affect your business or pleasure travel. Interestingly, symptoms are worse when you travel west to east, with the body requiring up to a day to recover from each time zone crossed. A person travelling from Winnipeg to Dubai, United Arab Emirates may take nine to 10 days to recover from the nine-hour time difference, but only needs five days to recoup from the flight home. Why? Jet lag seems to be worse when you lose time than when you gain it. It can also worsen as you age and, unfortunately, conditions that we experience with air travel, such as the changes in cabin pressure associated with high altitudes, low levels of humidity, the lack of physical movement and possible dehydration can increase symptoms regardless of time zones.
Frequent travellers who struggle with jet lag should consider seeing a sleep specialist or physician with training in sleep medicine. Light therapy, melatonin, prescription medication can all assist with symptom control. Travellers crossing multiple time zones, flying east, who are older adults and frequent flyers such as flight attendants and business travellers are at the highest risk of experiencing jet lag.