The human stress response remains the same as with our caveman ancestors—but today’s modern stressors aren’t the same. 

Back then, hormones like cortisol and adrenaline would spike during times of danger, such as running from a predator.

In the modern world, we often experience stress regularly, not in short bursts. 

We’re stressed at work, home, and just in general, thinking about a million different things at once. 

The result is a continuous stress response where our adrenals release cortisol, which then causes glucose levels to rise in our blood. 

Under normal circumstances, this is designed to help us physically escape the threat.

But our stressors here are often not physical; we aren’t usually using the energy to fight off a lion or run from a puma—but to beat a deadline or drive through rush hour traffic to get to an important meeting. 

These chronically high cortisol levels then weaken our immune systems, making us more vulnerable to infections.

Likewise, high levels of adrenaline may cause us to have enough energy to “power through” our tasks. 

And so we often find ourselves reaching for an extra cup of coffee to fuel the high that we feel from bursts of productivity.

Over time, however, our adrenals get tired of constantly releasing these hormones, leading us to feel tired but wired, where we’re physically and mentally exhausted but can’t get to sleep. 

Often, our energy levels skyrocket at inopportune times (like in the middle of the night) and then plummet during the day when we’re supposed to function normally.

Fatigue starts to set in as we struggle to get through the day, and the vicious cycle of reaching for caffeine and poor sleep throws our circadian rhythms even more off-kilter.

This is why women with PCOS may often feel “still tired” even after 8 hours of sleep or struggle with day-to-day tasks and stressors.

According to the PCOSAA, hormonal imbalance can cause you to feel sluggish and lethargic when you have PCOS.

Additionally, fatigue is a common indicator of a hormonal imbalance in the body.

As discussed earlier, cortisol plays a significant role in how we go through our daily lives and how tired we feel. 

The other key hormones that affect mood and energy levels are made by the thyroid, as well as reproductive hormones like estrogen, and testosterone.

If your thyroid doesn’t produce enough thyroid hormone, it can impact your energy levels and make you feel extremely tired. 

An overactive thyroid isn’t a good thing either, as it can also cause fatigue from producing too much thyroid hormone.

Meanwhile, testosterone in extremely low levels can lead to both weight gain and fatigue. 

Estrogen imbalances can also lead to a slew of symptoms like hot flashes, insomnia, and fatigue.

When you’re chronically stressed, your body reads it as a green light to continue dumping glucose into your blood to give you enough energy to physically run from your stressors.

And while it may sound appealing to run away from things that stress us out, it’s not like you can actually solve your problems by running a lap around the office the next time your boss asks for a report by noon!

Additionally, insulin resistance, which affects up to 80% of PCOS sufferers can also be caused by factors other than stress. 

These include diet, genetics, excess body fat, and physical inactivity.

The result is a surplus of sugar in our bloodstream, which can eventually make us less sensitive to insulin, leading to insulin resistance. 

Insulin resistance develops slowly and can make you feel more lethargic and sluggish as it progresses. 

Insulin resistance can also lead to fatigue because it hinders cells from efficiently accessing glucose for energy. 

Inflammation is part of your immune system’s response, and in the right amounts, it can be very beneficial in helping our bodies fight off infections and heal injuries. 

With PCOS, however, added factors like obesity and insulin resistance can cause inflammation.

However, long-term, chronic inflammation can worsen PCOS symptoms by encouraging the ovaries to produce even more testosterone, further throwing off hormone balance and causing tiredness.

Autoimmune conditions may also arise due to an overactivated immune system. 

Hashimoto’s thyroiditis, for example, causes the body to attack the thyroid. 

This affects the amount of thyroid hormones produced, causing problems like fatigue. 

The bottom line is that in a body with extremely high levels of inflammation, hormones can become even more imbalanced and make symptoms, including PCOS fatigue, even worse.

When you have PCOS, you need a consistent sleep schedule that will allow you to recharge and feel energized during the day. 

However, it’s often difficult to fall (and stay asleep) when you have PCOS because your hormones are off-balance.

Hormonal dysregulation affects your circadian rhythm, plus sleep disorders like sleep apnea can also occur alongside other PCOS symptoms. 

Put all those together, and you have a recipe for fatigue.

Sleep deprivation also reduces insulin sensitivity, increases cortisol, and raises inflammation overall. 

For example, poor sleep makes us reach for sweets and refined carbohydrates during the day to help keep our energy levels up—dumping even more sugar into the bloodstream and worsening insulin resistance.