Throughout the day, we experience different patterns of sleepiness, and we might ask ourselves what is regulating our sleep? Actually, sleep is governed by both sleep/wake homeostasis and the biological clock.
When we are awake for a long time, sleep/wake homeostasis tells us it is time to sleep, and it also helps us get enough sleep during the night to make up for the daytime waking hours; thus sleep/wake homeostasis balances wakefulness and sleep.
On the other hand, the internal biological clock dips and rises at different times throughout the day; for adults a strong sleep drive occurs between 1– 3 pm and between 2- 4 am, though this may vary depending on the person if he or she is a “morning” or “evening” person.
We experience different degrees of sleepiness during these times; it is less intense if we slept sufficiently and more intense if we did not.
Teens would witness a change in their biological clocks, which causes them to be alert at night, and with their early school times together with their other commitments, it can be difficult for them to get enough sleep.
There is a part in our brains controlling the biological clock called Suprachiasmatic Nucleus (SCN) that responds to dark and light signals; light reaches this part through the optic nerve of the eye telling the biological clock it is the waking time. The SCN also sends signals to other parts in the brain that play a role in making us awake or sleepy.
That is why dimming the lights at bedtime helps the SCN signal it is time for sleep. The biological clock disruptions like “jet lag” causes our conflict with our used sleep patterns, as the shift in light and time forces our bodies to adjust, and this is the reason for many travelers to have difficulty performing or thinking well.