by Tayyaba Bhatti and Wara Lounsbury
With the recent chill of November comes the ever-looming threat of exams. During these gloomy times we can find solace in the thoughts of the upcoming holidays. For some us, that entails a warm and cozy time spent with family and for others it means a trip to warmer climates. As pleasant and comforting as vacations are supposed to be, there is one unwelcome side effect: jet lag, which often casts a pall on the joyous times. But what exactly is jet lag? Previously believed to be a state of mind, jet lag was later discovered to be a physiological phenomena. Jet lag is the sensation of fatigue during daylight hours that arises due to the slow adjustment of our circadian clocks to new time zones. Circadian clocks are made up of the molecular pathways that dictate when we sleep, move, and eat, and are present in almost every cell in our body. Having to adjust these circadian clocks to a new time zone and then back to the original one within a span of a couple of weeks can take a toll on our bodies. However, there may be hope for frequent flyers in the future according to a recent publication in the journal Cell Metabolism.
The research started with an initial question: how do all circadian clocks show the same time? Universal clock resetting cues like feeding-fasting and temperature cycles have already been discovered. Dr. Gad Asher, the lead researcher on the study, decided to study oxygen consumption as a potential cue because all cells in our body use oxygen. The mice were placed in special cages to measure oxygen consumption and monitor blood oxygen levels. In order to simulate jet lag induced by traveling to a different time zone, researchers shifted the light-dark cycles of mice 6 hours ahead. They found that decreasing oxygen levels 12 hours before or 2 hours after the light-dark cycle shift helped mice to adapt to their new light-dark cycle more easily and recover from jet lag faster.
Furthermore, the researchers investigated the cellular route by which oxygen modulates the circadian clocks by removing a protein (HIF1α) that tells cells how and when to use oxygen. They discovered that when this protein was removed, the mice were no longer able to achieve the faster adaptation of the light-dark cycles upon exposure to decreased oxygen levels. Thus, they determined that HIF1α mediates the effect of oxygen on the circadian clocks.
This study incites a lot of new research questions. Most of us would want to know whether these findings can be applied to humans as well, or whether it's just mice that now have a cure for their jet lag. Another question that comes to mind is whether changing the oxygen level would work best before, during, or after a flight. Also, would raising oxygen levels have the same preventative effect as lowering oxygen levels? However, the most important question is how this research can be relevant to us.
Most of us experience chaotic sleep schedules during midterm and finals seasons. Some of us even suffer chronic fatigue due to ever-shifting circadian clocks during the year to meet deadlines or to socialize within our networks. Others struggle to maintain the heavy coursework with part-time jobs and night shifts. Since HIF1α also plays a role in various other cellular processes, this research may be extended to help explain the underlying effects of these phenomena surrounding fatigue. However, this requires further studying of the protein, its interactions within the body, and the application of oxygen consumption alteration to humans. For now, it appears just Stuart Little and his friends can rejoice over their jet-lag free vacations.