Why do most people get sleepy in the afternoon?
Why do they feel alert and energized around 10 in the morning?
Well, there is something that guides how we feel throughout the day
called the circadian rhythm.
This is a rhythm that is naturally occurring
and is built into the systems of the human body
along with plants and animals.
The term, circadian rhythm, was developed in the 1950s by a man
named Franz Hallberg who derived the term from the Latin words
circa which means “about” and diem which means “day”.
Therefore, the word literally translates into “about a day rhythm”.
Even though the term is relatively modern,
scientists have been aware of this rhythm for thousands of years.
Both the Egyptians and the Greeks had some understanding of the circadian rhythm.
There are several criteria that a biological circadian rhythm must follow.
First, it must last around 24 hours.
And second, the rhythm can be reset by exposure to light and heat.
This phenomenon can be seen as we travel across time zones
in the jetlag as our body slowly adapt to the new local time.
Recently, it has been concluded that disruptions to our circadian rhythm
can cause health problems.
Chronic disruptions of the circadian rhythm has been shown to cause
疲劳 失眠 有时联系到肥胖和糖尿病
fatigue, insomnia and is at times linked to obesity and diabetes.
At this point, you might be wondering
what happens during this 24-hour cycle,
what exactly happens during this rhythm.
If you take a normal day and break it down from sunrise to sunrise,
it may look something like this.
In the morning time,
our body experiences its sharpest rise in blood pressure
and a reduction in the secretion of melatonin.
These occurrences cause our bodies to feel awake.
It has been recently discovered that enjoying a cup of coffee first thing
might be counterproductive to your day.
In fact, early in the morning,
our bodies have the highest level of a hormone called cortisol
which makes us naturally feel more awake.
The caffeine and coffee actually interferes with cortisol production,
your body makes less of it accordingly,
in the body then relies more on the caffeine to feel awake.
By this logic then,
it is better to have a cup of joe in the early afternoon
so that the body does not become as dependent on caffeine to feel alert.
在下午 我们的机体有最佳的协调 反应时间
In the afternoon, our bodies have the best coordination, reaction time,
cardiovascular efficiency and muscular strength.
This gives us an explanation as to why so many world records
are broken in the late afternoon.
In the evening time, our body temperature begins to increase
along with the secretion of melatonin,
signaling to our bodies that it’s night time
and it’s time to go to sleep.
We hit our deepest stage of sleep around two o’clock in the morning.
Using this information is key to living a productive and happy life.
After all, it’s part of our nature
and the fight against nature is not easily won.
Anyways, it’s about 5:00 in the afternoon right now
so I’m going to go ahead and get ready for my afternoon run.
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