Sleep helps the body maintain precise hormonal timing, influencing everything from growth and repair to stress regulation. In this NightOwling lesson, circadian health expert and medical scientist Logan Pendergrast, Ph.D., explains how quality rest supports the natural rhythm of hormones like growth hormone and cortisol.
Dr. Pendergrast explores how disrupted sleep shifts these cycles, causing hormones to rise or fall at the wrong times and interfere with recovery, alertness, and relaxation. This lesson highlights how hormonal balance depends on when you sleep, not just how much — and why consistent rest is vital for steady energy, mood, and performance.
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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.
