3.1: Circadian Rhythms in Humans Animation Video
Circadian Rhythms in Humans
Physical, behavioral, and mental changes occur due to your body’s circadian rhythm. These naturally-occurring changes typically follow the 24-hour cycle of the sun and control when you feel tired and when you feel awake.
Your body naturally adjusts to provide better alertness and coordination during the day and deepest sleep at night. This is influenced by the rising of the sun. When the body senses light, it sends the body signals that result in activity. This is why you naturally wake up in the morning, and not in the evening.
The human body naturally experiences the sharpest rise in blood pressure around 6:45 a.m. to help aid in shaking off sleep.
Many people struggle to stay awake early in the morning. This may be because the body continues to secrete melatonin until about 7:30 a.m. Melatonin is a hormone that tells your body it is time to relax and go to sleep.
Once your body stops secreting melatonin, you reach the peak of alertness by about 10 o’clock a.m. By then, you are fully awake and ready to tackle the day.
Early afternoon provides the best time for physical activities due to your body’s natural functions. At 2:30 p.m. your body experiences its peak coordination.
Around 3:30 p.m. you will experience your fastest reaction time.
By 5:00 p.m. your body experiences its greatest heart efficiency and muscle strength.
As afternoon turns into evening, you should still feel wide awake.
Your body’s highest blood pressure occurs around 6:30 and your highest body temperature will happen around 7 o’clock p.m.
After the sun has gone down, your body senses a lack of light and begins to prepare to sleep. This usually occurs at about 9 o’clock at night. Bright indoor lighting, including the light from cell phones and televisions, can disrupt the body’s natural secretion of melatonin. This makes it difficult to fall asleep at night, which is why professionals typically recommend that people step away from screens a few hours before bed.
As you sleep throughout the night, your body rejuvenates itself. This makes it possible to do many things including thinking clearly and fending off infections.
At around 2 o’clock in the morning, you should experience your deepest sleep.
Your body facilitates a good night’s sleep by lowering its temperature. You should experience the lowest body temperature in the early morning.
Typically, your circadian rhythm should inform your sleep-wake cycle. Disruptions of your body’s natural circadian rhythm, such as jet lag, using electric lights at night, or working night shifts, can take a long time to overcome. For the best sleep, do your best to sleep with, not against, your body’s natural rhythm.