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Caffeine, Jet Lag, and Melatonin

One cup of tea or coffee in the morning will last much of the day, and should they have a second cup, even early in the afternoon, they will find it difficult to fall asleep in the evening.

Humans create their own endogenous circadian rhythm regardless of the presence of natural light. This twenty-four-hour bio clock is called the suprachiasmatic nucleus, and it controls a wide range of behaviors, such as wakefulness and sleep. This nucleus communicates to our brain whether it is day or night by using melatonin. Melatonin is released at night, and its function is to inform the brain and the body that it is dark. However, it does not play a direct role in our ability to fall asleep.

Not every person is the same: some are morning larks, some are night owls, and others are somewhere in between. This means that different types of people reach their peak productivity at slightly different times during the day. Moreover, this means that there are different points of time when they can fall asleep and wake up. Therefore, societal changes are required to produce more suitable and productive work schedules to accommodate all types of workers.

The invention of the jet engine had a negative impact on our circadian rhythm because it enabled people to travel through time zones quickly, resulting in jet lag. We feel tired during the day because, according to our internal clock, we feel as if it is nighttime. In addition, studies on airplane cabin crews have shown that they suffer from impaired short-term memory. The part of their brains responsible for learning has gotten smaller due to the stress of long-haul flights across many different time zones.

Sometimes we feel it is necessary to stay awake, so we use caffeine. Drinking beverages with caffeine later in the day means that your sleep will probably be disrupted. Still, when caffeine is fully eliminated from your system, your energy levels decrease rapidly.

Remember: If you could fall asleep a couple of hours after waking up in the morning, and if you cannot function before noon without caffeine, you are not getting enough sleep.

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