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Post by David on Oct 5, 2018 18:59:44 GMT
 The circadian rhythm acts as an internal body clock, determining how alert we feel throughout the day, allowing us to coordinate our behaviour with the natural environment.
For many years, experts have believed that sense of smell varies depending upon the individual, but a new study conducted at Brown University has discovered that our sense of smell varies throughout the day.
Over the course of a week, sensitivity to odour was measured in 21 male adolescents between the ages of 12 and 15 who would smell test sticks scented of roses every few hours, and their sensitivity was recorded.
Researchers found that their olfactory sense was often heightened in the hours before sleep, at around 9pm. These timings may influence eating patterns in humans, as heightened smell of food increases appetite.
The study also postulated that increased sensitivity to smell at dusk may be an evolutionary advantage, as the ability to detect carnivorous predators through odour rather than visual cues in poor or fading light may be an adaptive trait.
oupacademic.tumblr.com/post/167819934906/circadian-smell-cycle
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Post by David on Oct 5, 2018 20:58:39 GMT
I found such insight most educational...
How about you?
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Post by David on Oct 7, 2018 3:18:24 GMT
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Post by David on Oct 7, 2018 3:20:56 GMT
"All animals and plants have a built-in circadian rhythm, which is adjusted or entrained to the environment by external cues, known as Zeitgebers (a German word meaning “time-givers”), the most important of which is daylight. The brain’s internal circadian clock (also known as the biological clock, body clock, circadian pacemaker, circadian system, circadian oscillator, etc), which is centred in the hypothalamus region of the basal forebrain, uses these Zeitgebers to naturally synchronize or reset itself each day to within just a few minutes of the Earth’s 24-hour rotation cycle (the word “circadian” comes from the Latin words meaning “about a day”).
Early research in the 1960s and 1970s (including some famous experiments in caves) had concluded that the natural “free-running” circadian period of human beings was around 25 hours, not the expected 24 hours. However, later research (like that of Charles Czeisler et al in 1999) showed that these experiments were flawed, and that even the presence of electric lighting was enough to skew the results. It is now clear that, although individual circadian periods do vary – ranging between 23.5 and 24.5 hours in humans, dependent on variations in the person’s PER or period gene – they have a mean of around 24.2 hours, just slightly more than the Earth’s rotation. About 25% of people have a circadian period which is slightly less than the 24-hour day, and 75% have a circadian period slightly more than 24 hours.
The brain’s circadian clock regulates sleeping and feeding patterns, alertness, core body temperature, brain wave activity, hormone production, regulation of glucose and insulin levels, urine production, cell regeneration, and many other biological activities. The most important hormones affected by the circadian clock, at least insofar as they affect sleep, are melatonin (which is produced in the pineal gland in the brain, and which chemically causes drowsiness and lowers body temperature) and cortisol (produced in the adrenal gland, and used to form glucose or blood sugar and to enable anti-stress and anti-inflammatory functions in the body)."
www.howsleepworks.com/how_circadian.html |
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Post by David on Oct 7, 2018 3:24:12 GMT
I found such insight most educational...
How about you?
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