Sleep’s Impact on Your Body Systems

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Hello and welcome to today's night aling
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lesson. My name is Dr. Logan Pendergrst.
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I have a PhD in medical science and the
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focus of my research is on how the body
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is different between daytime and
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nighttime. So I'll be leading us through
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today's lesson which is the impact of
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sleep on the body systems. So sleep can
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be thought of as our body's main nervous
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system reboot. During quality rest, we
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see that the brain synchronizes our
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hormones. It synchronizes our immune
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signals and it helps us function
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metabolically. And it also synchronizes
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the communication between our organs.
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And when sleep is cut short, what we see
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is that there is a desynchrony between
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our organ systems that leads to
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increases in adrenaline and cortisol,
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which are hormones that are associated
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with stress and feeling stressed. And
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this can lead to a downstream uh effect
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on other bodily systems. And one example
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of this that's shown in the scientific
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literature is that one night of poor
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sleep affects the expression of up to
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700 different genes in the body. Meaning
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that at the cellular level, our bodies
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are affected by a poor night of sleep.
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So speaking of essential parts of our
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sleep process that make us feel good,
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we'll talk about REM sleep. So REM sleep
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it stands for rapid eye movement sleep
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and it is thought of as the cleanup crew
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part of our sleep process. During REM
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sleep, we see an activation of the
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body's glimpmphatic system which is
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responsible for clearing out a lot of
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the junk, a lot of these proteins and
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toxins that are accumulating throughout
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the day. They're recognized at this
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point and cleared out at an elevated
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rate versus when we are normally awake.
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Uh REM sleep also helps us to organize
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memories and our emotions. It helps us
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to compartmentalize experiences that
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we've had during the day and helps to
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support our learning and our decision-m
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functions. Inversely, we see that losses
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in REM sleep are thought to contribute
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to elevated feelings of anxiousness that
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we feel after a restless night. And in
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the scientific research, we see that the
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brain fluid flow, so the activation of
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this glimpmphatic system is 60% higher
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during REM sleep than it is during
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periods of wakefulness. Meaning that the
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brain is focused during REM sleep on
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cleaning itself up.
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So speaking of parts of the body that
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are affected by sleep, we'll move into
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talking about the nervous system. So the
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nervous system is the part of our body
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that sends and receives signals and
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helps to coordinate our actions, our
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thoughts and our sensations. And the
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nervous system breaks up into multiple
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parts, but one important part is the
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autonomic nervous system. Now the
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autonomic nervous system is basically
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just running in the background. It's the
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part of our nervous system that we're
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not really driving with our conscious
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thoughts. And that autonomic nervous
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system itself breaks up into two parts.
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One of those parts is the sympathetic
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nervous system and that is the alertness
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part of our nervous system that makes us
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feel activated. And the flip side of the
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coin of that if you will is the
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parasympathetic nervous system and that
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is the part of the nervous system that
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is responsible for making us feel
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relaxed. Now, the reason that I'm
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mentioning these parts of the nervous
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system is because after a night where
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we're experiencing deep sleep or
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effective sleep, we see a greater
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activation of the parasympathetic
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nervous system, meaning that we feel
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more relaxed and lower levels of stress.
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And this is actually shown in the
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research particularly by research that
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has been performed at Harvard where we
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see that individuals who sleep well have
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a 30% reduction in cortisol levels which
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cortisol is the primary hormone
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associated with feelings of stress. So
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moving from the brain into talking about
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the stomach, we're going to begin to
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talk now about how our gut is affected
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by poor sleep. Now, despite the fact
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that these areas of the body are so far
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away from one another, they're in
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constant communication. And we can see
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this when we look at what happens after
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a night of poor sleep. Poor sleep leads
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to an effect on the body's microbiome,
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particularly the guts microbiome. And
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what this does is it causes a increase
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in inflammation and an increase in
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cravings. Now, it's not just the
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microbiome that's responsible for this
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increase in cravings. We see that after
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a night of poor sleep, there is an
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increase in the release of a hormone
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that's released in the stomach called
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grelin. And that hormone is responsible
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for hunger. It's responsible for the
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feelings of hunger pangs. And
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additionally, we see that after a night
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of poor sleep, there is a decrease in
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the amount of release of a hormone
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called leptin. And this hormone called
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leptin is released from our fat cells
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and it makes us feel full. So we see an
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elevated level of grein which makes us
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feel hungry and a decreased amount of
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leptin which makes us feel full. So the
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combination of these two factors is
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responsible for driving individuals
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towards elevated levels of weight gain
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when they experience constant levels of
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poor sleep. And we see these effects
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actually measured in the uh scientific
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literature where one night of poor sleep
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increases levels of grein by 28% and
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decreases levels of leptin by 18%. Which
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is causing this perfect storm of seeking
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to eat foods, junk foods and elevated
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levels of calories when we're not
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sleeping properly. So what about other
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important parts of the body? What about
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for instance our heart? Well, as we
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would expect during sleep, our heart is
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resting. So, we see that our heart rate
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or the amount of beats that our heart
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has in a minute decreases. We also see
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that our blood pressure, so the amount
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of pressure that's feeling being
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experienced in the blood vessels
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decreases. And what this really means is
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that the heart is having its own system
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recovery time. And as we would expect
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when we're not sleeping properly or when
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we're not sleeping enough, we see an
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inflammation level increase in the blood
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vessels of the heart. But we also just
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see that it it there's a generally
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increased level of risk for heart
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disease. And when we measure this in
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individuals who have poor levels of
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sleep, we see that sleeping under 6
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hours chronically increases risk of
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heart disease by up to 20%.
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So next here we'll talk about metabolism
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and particularly how sleep affects what
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our body breaks down and how our body
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breaks it down. So sleeps helps us to
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regulate our sugar levels and how they
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are cleared from the blood. And it's
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during deep sleep that we see that our
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insulin sensitivity improves. And this
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improvement of insulin sensitivity helps
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us to clear sugar from our blood and put
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it into our muscles and our fat cells.
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And this is a good thing because if our
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sugar in our blood is elevated for long
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periods of time, it can actually damage
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other cells in the body. Uh,
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additionally with proper sleep, we see
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an improvement in the metabolism in our
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fat cells, meaning that those fat cells
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are able to take up energy and release
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energy more effectively.
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And then overall, we see that healthy
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sleep helps us to reduce our risk of
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type 2 diabetes. And this is shown in
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the science where we see that night
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shift workers who sleep less than 5
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hours per night have a 40% level
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increase and risk of type 2 diabetes.
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Meaning that our body and our sleep in
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particular is associated with diseases
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that we would otherwise think are not
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sleep associated. So next here we'll
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talk about the immune system. And the
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immune system is responsible for what we
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would expect which is our immunity. how
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our body fights off diseases and it's
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during slowwave sleep or what we call
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REM sleep as we mentioned in the last
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slide that we see an activation of our
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immune cells. We see that our immune
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cells are more effectively communicating
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with one another to remember and respond
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to antigens or disease-causing
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materials. We also see an increase in
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the release of cytoines which are
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proteins that our immune cells use to
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respond to diseases. Now if we flip
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this, we see that sleep loss leads to a
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compromised immune system function. And
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this is shown when we look at the
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science and we see that individuals who
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sleep less than 6 hours a day are four
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times likelier to uh obtain a viral
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infection or a common cold.
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So what about hormones? Well, each
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hormone in the body of course has its
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own function, but each hormone also has
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a specific time of day where it is at
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its most elevated point. An example of
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this is growth hormone, which is a
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hormone that is responsible for how our
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muscles grow. It's actually literally a
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hormone that is responsible for
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increasing the amount of growth and
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repair that we experience following
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exercise or daily activities. that
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hormone is at its highest during our
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slowwave or mid-stages of sleep. And
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another example actually of a hormone
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that is differing depending on what time
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of day it is is our cortisol levels. So
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I've mentioned cortisol previously as a
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hormone that is responsible for feelings
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of stress, but cortisol is also
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associated with feelings of alertness
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and it's typically at its most elevated
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point when we are just waking up. And so
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after a period of disrupted sleep, we
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see that these hormones are expressed or
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elevated at the times where they
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shouldn't be. So for example, we may see
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that if we're maybe sleeping poorly for
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a few nights in a row that our cortisol
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levels are peaking before we go to bed
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or before we go to sleep and that's
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interfering with our ability to go to
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sleep because we're feeling more alert.
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So what this really shows is that our
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hormones are not just each doing their
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own individual function, but they are
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also importantly elevated at times to
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help our body move more effectively
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throughout our day. So what about our
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skills? What about the types of things
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we need to do during our work or our
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daily lives such as driving a car or at
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work performing a surgery or operating a
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machine? Well, we see that deep sleep
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helps us to coordinate our motor
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function. And what this means is that
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our motor neurons that are helping us to
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move our muscles of our body are working
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more effectively when we've slept
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properly. We also see that this
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reduction in error that occurs from our
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motor neurons working better helps us to
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learn and consolidate new skills. And
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inversely we see that poor sleep
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interferes with our motor neuron
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function. And the equivalent to this is
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24 hours of lost sleep or staying up for
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24 hours straight is equivalent to about
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a 0.1%
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alcohol intoxication. So that equivalent
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is uh stark and noteworthy and can
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really lead to an infringement in upon
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our motor neuron function and our
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ability to operate machines and operate
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our day-to-day lives. And the folks at
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NASA have caught on to this and they
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have observed that poor sleep is
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affecting their pilots and they see that
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the pilots that sleep effectively have a
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30% reduction in the amount of errors
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that they commit.
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So finally, how does sleep affect our
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lives from an emotional standpoint?
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Well, after a night of good rest, we see
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a reduction in the action of an area of
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the brain called the amygdala, which is
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an area of the brain that's responsible
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for feelings of fear and anger.
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Additionally, after a night of good
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rest, we see an increased activation of
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an area of the brain called the
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preffrontal cortex. And the prefrontal
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cortex is responsible for our logic.
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It's responsible for our performance on
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functional tasks that are related to
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higher thinking. So what this adds up to
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is a period of good rest makes us feel a
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bit more patient, a bit more empathetic
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and helps us function a bit more from a
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higher reasoning standpoint. And this
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has been measured by the folks at
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Berkeley where they have seen that a
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night of poor sleep increases the
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activity of that amygdala, that fear and
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anger area of our brain by up to 60%.
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So to summarize today's lesson, we'll
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just mention that our sleep is not just
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important for making us feel rested uh
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every day, but it's also responsible for
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helping us coordinate the function of
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our organs, the release of our hormones,
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and even our emotional well-being. And
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that with disruptions in sleep, we see
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negative effects on all of these systems
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which can present itself as an increased
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risk of disease such as risk of diabetes
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and risk of heart disease. So what this
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tells us is that coordinating our sleep
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is important not just for our feelings
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but also for our relationships and our
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functions and our work. And so that is
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it for today's lesson. I will see you
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next time. This is Logan with Night
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Owling.