The Furry Clue to Treating Jet Lag: How the Degu is Helping Treat an Air Traveler’s Worst Nightmare

Even though we all love to sleep, fatigue caused by jet lag can be aggravating. [Unedited photo: “Sleeping” by RelaxedMusic, License: CC BY-SA 2.0]

Matt starts to crawl out of bed, having arrived home yesterday after a long flight. He feels dizzy and sees that it is 9 o’clock. This seems like a typical morning, but it isn’t. Actually, it’s not even morning. As Matt notices that the clock actually reads 9:00 P.M., he realizes that he fell asleep sometime in the afternoon and remembers that he was supposed to go on a dinner date. Groggy and now dateless, Matt starts to wonder when he will be able to sleep normally again. Sadly for him, he’s going to be up the entire night due to a sleep disorder all air travelers dread: jet lag.

Millions of travelers annually are affected by jet lag, which causes crippling fatigue during the day and alertness at night. People develop these irregular sleeping schedules when they travel across different time zones (“Jet Lag and Sleep,” 2013). For example, if you travel from Hawaii to New Jersey, you may experience jet lag, since New Jersey’s time zone is six hours ahead of Hawaii’s time zone. So, while your friends are playing a fun Monday afternoon basketball game, you may just be climbing out of bed. This is not because the Aloha State turned you permanently nocturnal – it’s because your body’s sleeping schedule is out of sync with New Jersey’s time.

Different time zones carve the United States, which is the reason why jet lag occurs. [Unedited photo: “US Timezones” by Rosie Rosenberger, License: CC BY-SA 2.0]

Jet lag is caused by the body’s inability to adjust its circadian rhythm to a new time zone. The circadian rhythm is basically a biological clock, and it is the 24 hour behavioral and physiological cycle found in numerous organisms (Hall, 1998). The circadian rhythm is the reason why you may get tired every night around 10 P.M., or why you get hungry at lunch time, or why you claim you need to use the bathroom to leave class every day.

The circadian rhythm is controlled by the suprachiasmatic nuclei (SCN), found in the hypothalamus of the brain. The SCN is the body’s central pacemaker. It is a group of about 16,000 neurons that receives information from external stimuli in order to control the cycle of internal processes (Mistlberger, 2005). As a result, the SCN is responsible for making sure our internal clocks are in sync with our external clocks.

Photic stimuli, or light cues, are the main signals that allow the SCN to set the circadian rhythm. When exposed to light, photoreceptors, such as rods and cones, in the eye get excited and send neural signals to the SCN (Refinetti, n.d.).

Our circadian rhythm initiates many internal physiological processes throughout the day. [Unedited photo: “Human Biological Clock” by Yassine Mrabet, License: GNU FDL]

Non-photic stimuli, such as food availability and temperature, also influence the SCN. However, these stimuli do not have as much impact as the photic cues from the photoreceptors (Refinetti, n.d.).

The SCN uses both the photic and non-photic stimuli to know when to secrete melatonin, the hormone that induces sleep. When we are exposed to light, the SCN tells the pineal gland to decrease melatonin production. On the other hand, when we are not exposed to light, the SCN tells the pineal gland to increase melatonin production to induce sleep (Dubuc, n.d.).

The jet-lagged traveler may see photic cues announcing it is time to sleep or get up, but the SCN is operating in a different time zone. Consequently, it is slow to adjust the rate of melatonin production.

Although it seems like just an inconvenience, jet lag can have much more severe implications than just missed basketball games or dinner dates. In addition to causing exhaustion, people with jet lag have reduced alertness, which can be very dangerous. Numerous fatal motor and plane accidents have been attributed to jet lag. Because of this, the FAA now even requires pilots to rest a minimum of 30 consecutive hours between flights so that they can overcome this sleep saboteur.

Light cues excite photoreceptors in the eyes, which then send signals to the SCN in the brain. [Unedited photo: “Circadian Rhythm” by National Institute of General Medical Sciences]

Believe it or not, much of our understanding of jet lag has come from research on the degu (Octodon degus), a small rodent that neither flies nor experiences jet lag.

This remarkable rodent can reset its circadian rhythm very easily. In fact, researchers at Stanford University discovered that the degu, which by nature is a diurnal species (meaning it is awake during the day), is able to completely shift its circadian rhythm and become nocturnal. It does this after being exposed to specifically timed light cues that alter its sleep cycle. Since humans are also a diurnal species, researchers hope that a similar treatment can be used for people (Edgar & Kas, 2000).

The same Stanford researchers discovered that the degu is also responsive to non-photic stimuli to adjust its circadian rhythm, which provides more insight into potential treatments. For example, exercise has helped the degu reset its biological clock, allowing the rodent to stay awake longer (Edgar & Kas, 1998). Additionally, orally administered doses of the sleep hormone melatonin have aided the degu in readjusting its sleep schedule, which makes this a possible treatment for humans (Madrid et al., 2007).

The degu is currently being studied to develop treatments for jet lag in humans. [Photo: “Degu” by Stan Hua, License: CC BY-SA 2.0]

Even more impressive, researchers found that the degu has an interesting ability to suppress recovery sleep caused by sleep deprivation. As a result, it can stay active even when sleep-deprived, suggesting that its circadian rhythm can oppose exhaustion to prevent irregular sleeping schedules (Edgar & Kas, 1999).

We have learned much about jet lag from this rodent, and this research is being applied today; one example is specially timed cabin lights on the new Boeing 787 Dreamliner aircraft to ease jet lag.

Maybe one day we’ll have ways to prevent jet lag, too… but until then, I’m going to catch some sleep. I just got back from Korea, and my jet lag is killing me.

Good night (afternoon?)!

In Brief:

  • Jet lag affects millions of air travelers annually.  It is caused by the body’s inability to adjust its circadian rhythm.
  • The degu has remarkable abilities to quickly change its circadian rhythm.
  • Research on the degu is providing insight to treatments for jet lag.

Works Cited

This article was written by cYw14. As always, before leaving a response to this article please view our Rules of Conduct. Thanks! -cYw Editorial Staff

cYw14

Author: cYw14

Hello there! I am a writer for cYw, and I want to thank you for visiting our blog. I hope you are enjoying the articles up here as much as I am. I love biology and writing, which is why I was so excited to have the opportunity to write for cYw. I find it fascinating how there are so many biological processes that occur simultaneously in my body in order to keep me alive and well. Moreover, I am inspired by all of the medical technologies that are being developed today to improve our lives, which is why I hope to study biomedical engineering in the future. Besides going to school, I also intern as a music therapist and work with special needs students, combining my interests in neuroscience and music. In my spare time I enjoy playing the guitar and going to concerts.

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2 Comments

  1. This feature article about the degu researchand jet lag led me to wonder if other nocturnal mammals are able to reset their circadian rhythm as well. Does anyone know about other potential organisms? Additionally, I wonder if aquatic marine organisms that travel great distances in short periods of time through various photic zones experience similar conditions as jet lag… Any thoughts?

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  2. I thought this was an extremely interesting article because everyone experiences this at least once in their lifetime. I recently got back from a trip to Korea and it was very difficult finding my sleep schedule again. As a high school student, I would find myself falling asleep after coming home from school and then waking up at 3 AM trying to rush through my unfinished homework. This article helped me to learn exactly why my body was behaving this way, both physically and scientifically. Because I went through the experience of having to juggle jet lag and schoolwork at the same time, I find it reassuring that the degu is being researched on to develop treatments for this problem. This brings me to think that future research and studies can be possible through other animals that behave the same way as well.

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