Around mid-April our guest speaker, Dr.
Cavanaugh, shed some light on the current understandings of the circadian
rhythm. Throughout the day the biophysical states and cognitive capacities of
our body and mind fluctuate. This results in time-dependent improved levels of
alertness, reaction time and muscle strength. The internal clock in which
regulates these fluctuations is known as our circadian rhythm, and it exists in
almost every animal as a mean to survive. We discussed how this endogenous
internal clock functions along with anticipation for environmental cues. When
environmental cues don't exactly much up to internal clock's anticipated state,
then misalignment occurs. This misalignment can also be characterized as jet
lag. Dr. Cavanaugh's study focused primarily on the misalignment of clocks
in Drosophila (the fruit fly). After exposing samples to artificial lighting at
unexpected hours of the day (night time), or to the darkness during the day,
the flies were acclimated to have misaligned rhythms in which affected their
behaviors such as sleep. This reduction in sleep ultimately yields to decreased
longevity in the male population of the fruit flies. His study not only looked
at the phenotypical effects of a misaligned clock but additionally the genetic
consequences of "jet lag". RNA sequencing (58.4 fold enrichment)
revealed an increased expression of down-regulated genes related to the lipid
and fatty acid metabolic processing. Cavanaugh noted that long chains were more
commonly seen than short-chain fatty acids. He was not sure yet if this has any
prevalence to the experienced phenotypes of the flies such as lessened life
span.
Dr. Cavanaugh stressed that the importance of his study was it's
translation to our current health issues in society. Due to the construction of
our 24-hour working society, there is a prevalence of social jet lag. Those who
work night shifts in America have been strongly linked to other impending
health issues such as obesity, cancer, stomach issues, and sleep disturbances.
Studies have suggested that the misalignment in one's circadian rhythm only
enhances their chances to develop the disease. The fruit fly study in which
showed reduced sleeping habits and intern, decreased longevity can only further
support this relationship. Dr. Cavanaugh then talked about possibly observing
the effects of social jet lag in a human subject experiment. This invoked my
interest to find an article in which may have done something
similar.
In a longitudinal study
by Smarr and Schirmer (2018), 3.4 million real-world learning management system logins
revealed that the majority of students experiencing social jet lag
correlated with decreased academic performance. Their study emphasized on the
resulted deficits of the misalignment between endogenous circadian rhythms
and the built environment. Unlike Cavanaugh's study, this experiment
measured learning and attention deficits. They hypothesized that a mismatch between the
student’s internal schedule and their forced school schedule would negatively
affect performance. I thought
this was really important and relevant for students to be aware of. This study
analyzed the login events of 14,894 Northeastern Illinois University students
for two years. The learning management login events were used to assess the
capacity for mapping the impact of social jet lag over large populations, while
still having the ability to generate individualized insights. Each student was
put into one of three groups in which indicated their most active hours of the
day (Morning, Noon, Evening). This was evaluated by the individual's login
habits and frequencies throughout the day. These differences in preferred
activity modeled the different stable phase alignments (chronotypes) within
individuals. The chronotypes were distinguished as being either early or late.
It was suggested that chronotypes are predominately determined by the genetic
composition of an individual's circadian clock. Regardless of differences in
chronotype, students are still obligated to attend class at the same
hours. The researchers suggested that performance can be adversely
affected if not during one's preferred/ most active time of day. This
study looked at the performance of students who had or did not have class
during their "peak time".
The NEIU students tracked composed of 50%
that had classes scheduled earlier than their peak time, and 10% later. This
mismatch was identified as “social jet lag”. As previously predicted,
student show had a mismatch between their preferred schedule (peak time) and
class schedule revealed to have lower grades. Results indicated a
majority of students experience more than 30 minutes of social jet lag on
average. There was a strong correlation between those experiencing
SJL with a significant decrease in academic performance. Students who
identified as having a later apparent chronotype experienced a greater decrease
in performance during day time.
This research gives insight into how innovations in data collection can help us make observations of a generalizable size population while maintaining an individual profile. It also imposes that social jet lag induced by limited schedule choices can infringe on academic achievements.
Why is it that the cultural bias of our society
favors the early bird? If our chronotype is determined by the genetic makeup of
our circadian clock, how are we all expected to perform at the same capacity at
any hour of the day? It is inherently impossible. The realities of a
diverse student population mean that not every scheduled class time can truly
work for everyone. It is important to be conscious of your chronotype in order
to navigate a lifestyle in which works with your body. This
will allow you to optimize the peaks of your cognitive capacities and overall
maintain consistently strong performances at work or school.
References:
Boomgarden, A. C., Sagewalker, G. D., Shah, A. C., Haider, S. D., Patel, P., Wheeler, H. E.,... Cavanaugh, D. J. (2019). Chronic circadian misalignment results in reduced longevity
and large-scale changes in gene expression in Drosophila. BMC Genomics, 20(1). doi:10.1186/s12864-018-5401-7
Smarr, B., Schirmer, A. (2018) 3.4 million real-world learning management system logins reveal the majority of students experience social jet lag correlated with decreased performance. Scientific Reports, Vol. 8. doi:10.1038/s41598-018-23044-8
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