In this lesson, circadian health expert and medical scientist Logan Pendergrast, Ph.D., explains how brain chemistry drives the sleep–wake cycle and what this means for shift workers. The video explores the role of key neurotransmitters and how their balance helps regulate sleep pressure, wakefulness, and mood. Dr. Pendergrast also breaks down two essential processes—the homeostatic sleep drive and circadian rhythm—and explains how they work together to maintain healthy rest and alertness.
The lesson highlights common chemical imbalances caused by shift work, including suppressed melatonin, elevated cortisol, and disrupted hormone timing, and why these patterns can affect mood, memory, and long-term brain health. Practical strategies are shared to counteract these challenges, such as managing light exposure, using caffeine wisely, keeping a cool and dark sleep environment, and adjusting meal timing. Together, these approaches help realign brain chemistry, improve sleep quality, and support long-term wellbeing for those working outside a typical 9–5 schedule.
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So moving on to our next factor and that
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is thermmore regulation or the
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regulation of the temperature in our
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environment and in our bodies. So just
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to give some numbers the ideal sleep
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temperature that is supported in the
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scientific literature is 16 to 19° C
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which equates to about 60 to 67° F which
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seems quite cold but what this does is
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it facilitates a drop in body
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temperature as we reach deeper stages of
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sleep. And this drop in body temperature
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should be about 1° C. And so what this
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does is it allows us to reach the deeper
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stages of sleep, the stage three and
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stage 4 stages of sleep. So that we can
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have more effective sleep architecture.
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And what happens actually is in these
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environments where we are overheated,
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let's say on a summer day with the
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window open, we're sleeping. Uh it it
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interrupts our sleep architecture. we're
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prevented from reaching the deeper
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stages of sleep and we feel less rested
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upon waking. So, there are things that
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we can implement to facilitate this. Of
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course, there's cooler bedding options,
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sleeping perhaps with a thinner sheet
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rather than a heavy blanket or using
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fans or of course air conditioning to
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improve the amount of temperature that
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we're experiencing to keep it at a lower
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threshold so that we're able to drop our
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body temperature. And then an additional
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tip that we can um that we can utilize
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here that it that helps us hack our
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bodies in some way to prepare for the
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drop in temperature during sleep is to
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take a warm shower about an hour before
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bed. And what this does is it dilates
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the blood vessels in the periphery or
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the outer parts of your body. And when
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those blood vessels dilate, your body is
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better able to get rid of the heat
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that's in it. And so this facilitates us
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to lower our body temperature and sleep
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more effectively.
