Read Online It Starts With Food: Discover the Whole30 and Change Your Life in Unexpected Ways by Melissa Hartwig, Dallas Hartwig - Free Book Online
Authors: Melissa Hartwig, Dallas Hartwig
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cortisol.
CORTISOL
Summary: The “stress hormone” secreted from the adrenal glands to help the body recover from an acute fight-or-flight stress response. It is secreted in response to low blood sugar, physical or psychosocial stress, intense and prolonged exercise, and sleep deprivation. Cortisol plays a key role in salt metabolism, blood pressure, immune function (having immunosuppressive and anti-inflammatory effects), and energy regulation. It raises blood sugar by stimulating glycogen breakdown. Chronically elevated cortisol promotes insulin resistance and tends to elevate leptin levels.
Cortisol has a circadian rhythm that coincides with the light-dark cycle. Cortisol is highest just before waking, functioning as a “get up and go” hormone during the early morning hours. It mobilizes energy for activity and helps to fire up your nervous system so that you (mentally) feel more like Einstein than like Homer Simpson. Cortisol levels then decline rapidly as the day progresses, remaining low in the late evening and overnight, helping you to relax before bed and sleep well until morning.
LIGHTS OUT
It’s normal to have higher cortisol levels first thing in the morning, but artificial light (including the light from your TV, computer, and mobile phone) after dark tells your body it’s still daytime. This does not allow you to hormonally “wind down” in the evening, which promotes that “tired but wired” effect. Sending your brain daytime messages right before bed also upsets normal hormonal responses (like melatonin secretion) when you’re sleeping, so you don’t get adequate deep, restorative sleep. That sleep, and normal cortisol rhythms, are important for memory formation and future access. Now, where did you put your highlighter?
Cortisol secretion is tied to many factors (like sleep, exercise, and psychological stress) but is also influenced by your eating habits. One of cortisol’s jobs is to help glucagon keep blood sugar within a healthy range. When your body senses that blood sugar is too low (like when you haven’t eaten for a very long time) or if it crashes too fast (as they tend to do following a blood sugar spike when you’re insulin resistant), it reacts to that stressful situation by releasing cortisol. Cortisol then prompts glucagon to get to work, breaking down energy stored as liver glycogen (or muscle tissue) and flooding it into the bloodstream as a response to your volatile blood sugar levels.
The trouble comes when your actions (dietary or otherwise) tell your body that you’re very stressed all the time . This causes your adrenals to release cortisol all the time . And when cortisol gets rowdy, it creates all sorts of trouble—some of which is going to sound awfully familiar.
Being chronically underslept, constantly over-exercising, or experiencing chronic psychological stress—a hallmark of modern life—can all trigger unhealthy levels of cortisol in the body. But so can prolonged periods of not eating (extended fasting), or eating too little (excessive calorie restriction).
Fasting—when you don’t eat for eight, twelve, sixteen hours—is somewhat stressful to the body and may elevate cortisol levels, which only adds more stress to your already overstressed system. Cutting too many calories (which we’re pretty sure you’ve done before) is also profoundly stressful and also elevates cortisol levels.
Want to know another reason that skipping meals and restricting your calories doesn’t work for long-term weight loss? Because chronically elevated cortisol sends a variety of messages via different hormonal pathways, all designed to do one thing— preserve body fat . In fact, chronically elevated cortisol levels actually erode your muscle mass, leaving you with more fat and less muscle.
Now we have your attention.
Chronically elevated cortisol impairs glucose uptake from the bloodstream and enhances the breakdown of glycogen in the liver—both leading to more
CORTISOL
Summary: The “stress hormone” secreted from the adrenal glands to help the body recover from an acute fight-or-flight stress response. It is secreted in response to low blood sugar, physical or psychosocial stress, intense and prolonged exercise, and sleep deprivation. Cortisol plays a key role in salt metabolism, blood pressure, immune function (having immunosuppressive and anti-inflammatory effects), and energy regulation. It raises blood sugar by stimulating glycogen breakdown. Chronically elevated cortisol promotes insulin resistance and tends to elevate leptin levels.
Cortisol has a circadian rhythm that coincides with the light-dark cycle. Cortisol is highest just before waking, functioning as a “get up and go” hormone during the early morning hours. It mobilizes energy for activity and helps to fire up your nervous system so that you (mentally) feel more like Einstein than like Homer Simpson. Cortisol levels then decline rapidly as the day progresses, remaining low in the late evening and overnight, helping you to relax before bed and sleep well until morning.
LIGHTS OUT
It’s normal to have higher cortisol levels first thing in the morning, but artificial light (including the light from your TV, computer, and mobile phone) after dark tells your body it’s still daytime. This does not allow you to hormonally “wind down” in the evening, which promotes that “tired but wired” effect. Sending your brain daytime messages right before bed also upsets normal hormonal responses (like melatonin secretion) when you’re sleeping, so you don’t get adequate deep, restorative sleep. That sleep, and normal cortisol rhythms, are important for memory formation and future access. Now, where did you put your highlighter?
Cortisol secretion is tied to many factors (like sleep, exercise, and psychological stress) but is also influenced by your eating habits. One of cortisol’s jobs is to help glucagon keep blood sugar within a healthy range. When your body senses that blood sugar is too low (like when you haven’t eaten for a very long time) or if it crashes too fast (as they tend to do following a blood sugar spike when you’re insulin resistant), it reacts to that stressful situation by releasing cortisol. Cortisol then prompts glucagon to get to work, breaking down energy stored as liver glycogen (or muscle tissue) and flooding it into the bloodstream as a response to your volatile blood sugar levels.
The trouble comes when your actions (dietary or otherwise) tell your body that you’re very stressed all the time . This causes your adrenals to release cortisol all the time . And when cortisol gets rowdy, it creates all sorts of trouble—some of which is going to sound awfully familiar.
Being chronically underslept, constantly over-exercising, or experiencing chronic psychological stress—a hallmark of modern life—can all trigger unhealthy levels of cortisol in the body. But so can prolonged periods of not eating (extended fasting), or eating too little (excessive calorie restriction).
Fasting—when you don’t eat for eight, twelve, sixteen hours—is somewhat stressful to the body and may elevate cortisol levels, which only adds more stress to your already overstressed system. Cutting too many calories (which we’re pretty sure you’ve done before) is also profoundly stressful and also elevates cortisol levels.
Want to know another reason that skipping meals and restricting your calories doesn’t work for long-term weight loss? Because chronically elevated cortisol sends a variety of messages via different hormonal pathways, all designed to do one thing— preserve body fat . In fact, chronically elevated cortisol levels actually erode your muscle mass, leaving you with more fat and less muscle.
Now we have your attention.
Chronically elevated cortisol impairs glucose uptake from the bloodstream and enhances the breakdown of glycogen in the liver—both leading to more
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