Experts have found that the impact of jet lag goes far beyond making us feel tired, and that flying across different time zones can actually affect our internal organs. Caroline Wellbery, a professor in the Department of Family Medicine at Georgetown University, has revealed the extent of these effects and how to avoid them.
In an article for the Washington Post, Professor Wellberry writes:
“Given what is known about the importance of intestinal bacteria (called the microbiome) and their connection to immune function and well-being, it’s clear that any discussion of jet lag, and how to deal with it, needs to consider ‘gut lag’ as well.”
This so-called gut lag comes along with stomach issues such as diarrhea, constipation, or appetite fluctuations. Professor Wellberry explains that the shock to the body from international travel begins with the disruption of the circadian clock, which coincides with the Earth’s natural cycles of light and darkness.
To some extent, our internal organs rely on this rhythm to stay on schedule, which explains why sleep deprivation can affect our mood, mental alertness, hunger, and even our heart function.
The body’s core temperature, which drops during sleep, is usually at its lowest between two to three hours before waking. According to Professor Wellberry, the point in this cycle when we wake up influences how sleepy or well-rested we feel.
“When you fly into a new time zone, your core body temperature doesn’t recognize that change and instead continues to dip according to the schedule of the place you have left,” writes Professor Wellberry.
“If you are awake or wake up before the dip, you are much more likely to feel groggy or out of sorts, especially if you are exposed to light while your body temperature drops.”
“That’s because light and temperature signals come into conflict with each other: The light tells you that you’re wide-awake; the temperature signal tells you that you’re about to enter the deepest point in your sleep. This is when you will mostly strongly feel the unpleasant symptoms of jet lag.”
When traveling across time zones, adjusting our exposure to light and darkness can help to offset the effects of jet lag. “The basic idea is to stay in darkness before core temperature dips in reaction to your regular sleep schedule, and to get light exposure after the dip,” says Professor Wellberry.
To help prevent jet lag, it is recommended to nap before an international flight to help get ahead on rest. It is also advised to avoid coffee and alcohol, which can worsen the effects of jet lag. Sleeping on the plane is only recommended if will be night time when you arrive at your destination. In addition, a melatonin supplement may help to improve the quality of sleep you get during your time abroad.
To combat “gut lag,” staying hydrated and adjusting to meal times in the new time zone right away will help to keep bowel movements regulated.
Professor Wellberry’s article in the Washington Post, “Why crossing time zones makes you feel bad, and what you can do about it,” was published on July 21st.