It is official: jet lag is worse going east than going west. The journey home from San Francisco leaves you more tired than the journey there.
The best strategies to assist in adjusting the biological clock for westward travel are to gradually shift the sleep schedule and seek out natural sunlight exposure and exercise during daylight.
According to Derk-Jan Dijk, director of the Surrey Sleep Research Centre, melatonin helps but has its limitations. It is effective for speeding up the biological clock, particularly after eastward flights, but it does not help in slowing it down.
Melatonin, referred to as the “darkness hormone,” is released by the pineal gland, peaking during the night and decreasing with morning light, facilitating easier sleep.
A 2002 study combining five randomized controlled trials found that individuals taking melatonin rated their jet lag experiences as half as severe as those on placebo, on a scale from 0 to 100.
This indicates that melatonin might be more beneficial after eastward flights, where you need to sleep earlier than your body’s natural inclination, compared to westward flights that require staying awake longer. Fortunately, those traveling west have other strategies to help their biological clocks adjust, such as gradually shifting their sleep schedule in the days leading up to the flight and ensuring exposure to natural sunlight and exercise during daylight hours at their destination, which can help regulate melatonin production.
Melatonin, often referred to as the “darkness hormone,” is released by the brain’s pineal gland when the sun sets. Its production peaks in the middle of the night and gradually decreases with the return of morning light. While it is influenced by the biological clock, light exposure plays a crucial role in regulating this cycle, keeping melatonin production in sync with the day-night pattern. The increase in melatonin at night induces a state that makes falling asleep easier. Conversely, taking melatonin during the day can also induce sleepiness.
Disruptions in melatonin production can result in sleep disorders. For example, individuals who are blind do not have their biological clocks aligned with light changes. Their natural clock, which runs slightly longer than the 24-hour cycle, can lead to misalignment between their melatonin production and the external day-night cycle, causing them to sleep during the day even if they do not intend to.
Similarly, jet lag can disrupt melatonin production. This occurs partly due to interruptions from bright cabin lights during flights, but more significantly when arriving at a destination with a different day-night cycle than one’s biological clock. It may take several days for the clock and melatonin levels to realign.
As a result, the use of melatonin supplements to manage jet lag has gained popularity. However, evaluating their effectiveness is challenging. Controlled experiments that alter participants’ biological clocks and reflect real-life situations are difficult to conduct. For instance, many studies that deliberately kept subjects awake with bright lights throughout the night are not only ethically questionable but also do not accurately represent sleep disruption.
Instead, researchers have administered melatonin to individuals who traveled in real-life scenarios, such as flight crew, military personnel, and scientists attending conferences. In these contexts, the supplements appear to be effective. A significant study published in 2002, which combined data from five randomized controlled trials, found that individuals taking melatonin reported their jet lag experiences as half as severe compared to those receiving a placebo, on a 0 to 100 scale.
In any American pharmacy, you can find melatonin in various forms, from tablets and pink gummies to potent capsules, all marketed to alleviate the unwanted effects of jet lag. But does it actually work? The jury is still out on that.
