The human body appreciates rhythm, movement, and nourishment. Our hunter-gatherer ancestors supported this by waking up with the sunrise, being active during the day, and going to bed with the sunset. The invention of the light bulb has hugely impacted our lifestyles and changed our rhythm. There was no hunting and gathering in the dark, there was also no insomnia and chronic fatigue!

Our bodies like homeostasis and they achieve this best with routine and rhythm.  Chronic stress has become the way many people live their lives these days as they are overworked and under-recovered.  Most people don’t yet understand the risk associated with such high levels of stress.  Our body passes through an “alarm stage” where it pumps out high levels of adrenaline and noradrenaline hormones to help us “fight the tiger.” High levels of these stress-related hormones play havoc on our sex hormones and our sugar management hormones, which both play a critical role in energy levels, the storage of body fat, and the health of our immune system.

You may have trouble controlling the many stressors in your life, but there are some lifestyle factors that you do have control over that can help lower your overall stress hormones. This is what this entire series of blog posts is all about.

When the sun comes up, our adrenal gland releases hormones that give us energy.  Cortisol is the main hormone that makes us jump out of bed.  As the day passes cortisol levels should slowly drop and leave us feeling sleepy.


When the sun goes down other hormone are released to helps us sleep.  One of these hormone is called serotonin (precursor to the hormone melatonin), and it should have an inverse relationship with cortisol.  

-       When cortisol is high (hopefully in the AM) serotonin is low.  
-       When cortisol is low (hopefully in the PM) serotonin is high.  

Cortisol determines if you are sensitive to serotonin or not. If you have high levels of cortisol, the serotonin receptors in the brain are desensitised to serotonin.  This is the start of anxiety and depression.  Anti-depressant drugs can increase the serotonin levels which can help for a short period, but if you don’t attack the cause of the stress, you cannot cure depression.

Cortisol is not always a harmful hormone, cortisol gets us out of bed, it makes us feel alert, and it gives us the energy to think and move.   The right amount of cortisol at the right time of day can help us to hunt, gather and reproduce.  Without cortisol, we would not survive.  However, we have a limit to how much cortisol we can produce on a daily basis; it’s not an unlimited resource. If the demand for cortisol exceeds the levels of production, we start to head down the rabbit hole of adrenal fatigue.

Any disruption of homeostasis is a stressor. A stressor is anything that makes a physiological change in the body.  Emotional stress, mental stress, physical stress all raise cortisol levels.  They all use up our cortisol stores.

The human body likes routine and rhythm; if you are the type of person who exercises in the PM, or stays up late working or watching TV, your body will try to save cortisol for the evening.  The body can only make so much cortisol in a day, so instead of having a big surge of cortisol at the start of the day, the body saves the cortisol because it knows it’s going to need it for the nocturnal activities.  Not only does this have an impact on your sleep, but it has implications on other hormones in the body like serotonin, melatonin, growth hormone, insulin, and more.

If you want to know the best way to fuck up your body, store additional body fat, lower energy levels, lower your libido, decrease your immune function, impact your digestive health, impact your recovery and increase the chances of illness and even death, look no further! The human body LOVES the natural hunter and gatherer rhythm; if you try to push the body out of this rhythm, you will suffer the consequences.

If you remember from PART 1 of Eat, Sleep, Train Repeat we wrote about Autonomous Nervous System (ANS) and its two states: sympathetic (fight or flight) and parasympathetic (rest and digest). The sympathetic state is supported by the hormones that give us energy like adrenaline and cortisol. The parasympathetic state is supported by hormones that help us relax, digest and sleep, so it’s no surprise that serotonin supports the parasympathetic state.

You may have heard that 90% of serotonin is made in the gut. The parasympathetic state (rest and digest) is closely related to activities in the gut and the health of the gut.  High levels of sympathetic state (cortisol) can cause digestive and absorption issues in the gut which can impact our health, performance and recovery abilities.

A healthy hormone balance is one that supports high cortisol in the AM and low cortisol in the PM.  This is not always the case, and lifestyle factors can drastically impact the ANS and the hormones that control it.

  • If the alarm goes off in the morning and you wake up feeling groggy, low on energy, or you continue to hit the snooze button, it’s a sign that your cortisol is low. This is not a good thing; we should jump out of bed in the morning ready to attack the day.

  • Are you low on energy during the day? Do you need stimulants like coffee to give you energy? Again, your cortisol levels are low, and hence your energy is low. Your brain craves sugar, high energy foods, or coffee to give you energy.

  • Do you need to take a pre-workout supplement before you train? Many of these supplements elevate cortisol which can have adverse effects on your workout, your recovery, your cortisol balance and your ability to sleep that evening.

  • Are you full of energy at 10 pm? If so, this is a sign that your cortisol levels are high at the wrong end of the day.

We can retrain our body to resynchronize cortisol production if we start to change our lifestyles.  

We will talk more about this in the next post