Researchers from Israel have found that oxygen is a vital component to the circadian rhythm, the internal clock that allows the body’s cells to work in unison at different times of the day.
Eating and temperature regulation, two mechanisms that are known to influence the circadian rhythm, were determined to be heavily influenced by our oxygen intake. The research team monitored the oxygen levels present in mice and determined that the subjects consumed more oxygen when exposed to darkness, as they are nocturnal mammals.
Our bodily functions are regulated by oxygen
Mammals have a circadian rhythm that is controlled by a biological clock located in the brain, which is able to control any group of cells that perform specialized functions. The clock allows these cells to share information about the fasting and feeding periods and how body temperature changes throughout the day.
Because oxygen is always available in the body, researchers suggest that it might have global implications for the cells that adhere to the circadian rhythm, a hypothesis that had not been tested until now.
The daily variations of oxygen levels of mice were analyzed and it was discovered that oxygen deprivation for as little as two hours allows the body to adapt quicker to a change in circadian rhythm, or in other words, oxygen deprivation is a cure for jet lag.
To test this, researchers compared the oxygen consumption levels of mice in both dark and light phases. An increased level of oxygen in the blood and in peripheral tissues was in place with the subjects’ feeding and period of highest activity.
The mice were determined to have to 12-hour light-dark cycles. They were exposed to 21 percent of oxygen in the dark phase and to 16 percent in the light phase. Then, researchers altered the lighting schedule, causing jet lag on the subjects so they reduced oxygen levels to 14 percent for two hours. This proved to be enough for letting the mice adapt to their new circadian cycle.
Then, researchers altered the lighting schedule, causing jet lag on the subjects so they reduced oxygen levels to 14 percent for two hours. This proved to be enough for letting the mice adapt to their new circadian cycle.
Coincidentally, oxygen levels of an airplane’s cabin usually correspond to 16 percent O2, which is now being increased to 21 percent. Researchers advise that this modification should be reconsidered seeing that there is new data that reveals how to cure jet lag.
The critical component in this discovery is a protein known as HIF1α, which has a key role in oxygen balance on the body. When the subject is exposed to regular oxygen levels, the HIF1α protein degrades rapidly, but whenever oxygen levels decrease, the depletion of HIF1α stops and it starts to accumulate.
It was also discovered that HIF1α is not critical for the internal clock, but actually serves as the molecular link between oxygen and the circadian rhythm.
“We found that a moderate reduction in oxygen levels for a short period accelerates the adaptation of wild-type but not of HIF1α-deficient mice to the new time in a jet lag protocol. We conclude that oxygen, via HIF1α activation, is a resetting cue for circadian clocks and propose oxygen modulation as therapy for jet lag,” the study reads.
How to deal with jet lag
Jet lag is usually attributed to people who travel across time zones who become drowsy, but the same disorder can occur in people that change their work shifts with frequency, those that sleep late and wake up early, and those that sleep in periods that become unstable when subjected to a 24-hour timeframe.
Until now, the only treatment for curing these types of disorders was trying to expose the body to different types of stimuli before going to sleep, or altering stimulating factors and practices like watching TV at night or using a white noise machine.
Adults need at least 7 hours of sleep a night. Some people sleep only 6 or even 10 hours each day. The need of sleep changes per individual, but the determining factor seems to be the feeling of sleepiness throughout the day, which indicates that the person has not slept enough.
A common treatment is using melatonin, a hormone that is naturally excreted by the pineal gland. Melatonin is the hormone responsible for sleep cycles. Foods can contain melatonin and it is available at drug stores.
Melatonin levels also vary depending on the circadian rhythm, as the highest levels are usually attained in the late evening and they remain so throughout the first hours of the night.
It is known that melatonin is heavily influenced by light, and it is frequently used by those that have to adjust quickly to new circadian rhythms. The side effects of melatonin are quite tame, as the most severe are sleepiness and minor changes in blood pressure.
Melatonin intake may cause insomnia, to which patients are advised to reduce the dosage. Adults are usually prescribed from 0.2 to 20 mg of melatonin and it is usually considered safe for consumption.