For as long as life has
existed on earth, there have been predictable patterns of light and dark, day
and night. With that knowledge, it is no
surprise that life on earth has adapted and created endogenous circadian clocks
so that certain functions that we need during activity times are optimized. The question, however, becomes what happens
when this rhythm is disturbed? The
answer is nothing good, sleep is very important for various reasons as we shall
see.
Daniel Cavanaugh’s article describes the
concept known as chronic circadian misalignment (CCM) which is defined by a “behavioral
schedule that runs outside the dictates of their endogenous circadian rhythms”
(2). To test out the effects of CCM on
an organism, he and his colleagues chose the drosophila melanogaster. The
experimental design consisted of introducing 4-hour phase delays into the daily
life of the fruit fly. The results consolidated
the belief that a lack of sleep leads to decreased health. Specifically, for the fruit fly, it was found
that CCM cause a 15% decrease in the lifespan of male and female flies alike. This turned an average 40-day lifespan to a
30-day lifespan which is very significant.
This decline in longevity of the flies can be attributed to gene
expression changes that upregulate cellular stress-related genes and downregulate
genes responsible for biosynthetic and developmental processes. Among other locomotive problems, the main
takeaway from the experiment was that “organisms function best when the
difference between endogenous circadian period and environmental cycles is
small” (12). The importance of this
study is that CCM is not an exclusive phenomenon to fruit flies, it is equally
as impactful to us as well.
Sleep
is restorative but often times college students are unable to justify sleeping
long in order to keep up with daunting classes and heavy course loads. In an interview with a college student, neurologist
Shelley Hershner, speaks of the everyday implications of a lack of sleep or CCM. The article begins with the statistic that
70-96% of students get less than 8 hours of sleep a night. Hershner states that students who sleep more
or take naps tend to have increased performance in school leading to a higher
GPA. Although this may be unsurprising
to us students, she goes on to state that a lack of sleep causes a reduced
immune response, decreased memory, and impaired locomotive skill. To go along with the Cavanaugh experiment,
this decreased immune response is similar to how the drosophila had the downregulation
of key immune system genes. With all
these negatives, there are still many students who cannot afford to sleep the
biologically adequate amount due to extraneous variables such as having to work
jobs during school on top of studying.
Wendy, the college student who Hershner is speaking to, wakes up early
in the morning for work and then goes to sleep late studying. She often reports herself feeling very tired
throughout the day but firmly states that it is the only way to balance her
life. Her tired feeling directly correlates
with the aforementioned idea that organisms function best when environmental
cycles and endogenous cycles have little disparity. Her days starting in the dark and ending in
the dark are clearly not helping her productivity or health.
Though
it may seem that small disturbances that affect creatures like drosophila
should not disturb us, we are no less susceptible to the damages of a bad sleep
schedule. So next time you have to
choose between pulling an all-nighter or studying effectively, go to sleep.
Citations:
Cavanaugh, Daniel J.
“Chronic Circadian Misalignment Results in Reduced Longevity and Large-Scale
Changes in Gene Expression in Drosophila.” BMC Genomics, BioMed Central,
7 Jan. 2019, bmcgenomics.biomedcentral.com/articles/10.1186/s12864-018-5401-7.
Hershner, Shelley. “Is sleep a luxury that college students
cannot afford?” Journal of National Sleep Foundation. 2015, https://www.sleephealthjournal.org/article/S2352-7218(14)00011-4/pdf
Eye-opening and well written!!
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