As far back as 350 B.C., Aristotle theorized that sleep provides physical renewal, yet in the age we live in with our fast paced environment, technology driven timelines, and our quest to be all we can be, a good nights rest has fallen by the wayside.
The body’s clock runs roughly on a 24 hour cycle known as the circadian rhythm. It’s influenced by the amount of light that enters our eyes, which triggers our brain to produce more or less of the hormone “melatonin” which causes drowsiness. Sleep is a far more active process than once thought. While you’re sleeping, your brain and body are hard at work. Let’s study this “body clock” more closely. We’ll start at noon. You are hard at work or doing daily task at home or just hanging out at the beach. Your fastest reaction time during the day is 3:30 pm. Next you’re at home having dinner, watching the television, or working outside. Your highest blood pressure occurs at 6:30 pm. Having finished your day you turn in for the night at 11:30 pm after watching your local news program. While you may drift off to sleep at around midnight, your deepest sleep won’t happen until 2:00 am. From midnight to 2:00 am you are in what’s known as a “light sleep”.
In a light sleep, your eyes stop moving, your body temperature drops, and both heart rate and breathing are steady, and brain activity slows. Your brain is also at the point where it tunes out external noises. but it also shows burst of activity called “sleep spindles” which plays a role in learning and incorporating new memories. In your deepest sleep, your muscles relax, blood pressure drops, and breathing slows. This is the condition that you would experience if you were to take a long space journey in suspended animation and waking during this phase often leads to grogginess. Deep sleep is the most physically restorative phase of the sleep cycle and is thought to be important for maintaining memories. This part of sleep is also associated with Rapid Eye Movement, or REM, the part of sleep where dreams occur. To have a restful sleep you must be in the REM phase, and you must dream. You may not remember them, but if you woke up totally refreshed, then you did dream. Unless you didn't reach the deep sleep phase meaning you didn't dream and that's why you woke up still tired.
Now back to the body clock. At 4:30 am your body reaches its lowest temperature, and at 6:45 am your blood pressure jumps drastically. A great number of heart attack deaths have happened at this point of the day and that’s why taking caffeine at this point should be done so with extreme caution. Ease into that first cup. Recently it was concluded that one of the functions of sleep was to help cleanse cellular waste that naturally builds up in the brain during the day.
Oh, and by the way, after years of research, dreams are still a mystery. Any explanation is piecemeal and as Patrick McNamara, who is a dream specialist says, “We want one theory that could elegantly account for everything we see in our dreams and whether or not that’s ever going to be possible is up for grabs.” Something to sleep on, wouldn’t you say?