How High Cortisol Disrupts Your Sleep and Leaves You Exhausted

Struggling to fall asleep or waking up feeling like you barely got any rest? You might be blaming a late-night Netflix binge or that afternoon coffee, but the real culprit could be something deeper. High cortisol levels may be silently sabotaging your sleep, leaving you in a cycle of exhaustion that no amount of rest seems to fix. Cortisol is your body’s main stress hormone, and while it plays a crucial role in energy and metabolism, too much of it, especially at the wrong times, can wreak havoc on your ability to sleep. If you find yourself wired but tired, constantly running on empty, or waking up exhausted no matter how many hours you spend in bed, it’s time to take a closer look at how stress hormones are affecting your sleep.

The Role of Cortisol in the Body

Cortisol isn’t the villain it’s made out to be. In fact, it’s essential for survival. Produced by the adrenal glands, cortisol helps regulate metabolism, blood pressure, immune function, and the body’s response to stress. It also plays a key role in maintaining the sleep-wake cycle, following a natural rhythm where it peaks in the morning to help you wake up and gradually decreases throughout the day to allow for restful sleep at night.

This process is controlled by the hypothalamic-pituitary-adrenal (HPA) axis, a system that regulates the body’s stress response. When stress is short-term, cortisol spikes help you stay alert and focused. However, when stress becomes chronic, the HPA axis can become dysregulated, keeping cortisol levels high when they should be tapering off. This leads to disrupted sleep, fatigue, and an overworked nervous system. Research has shown that elevated nighttime cortisol is associated with sleep disturbances and increased risks of metabolic disorders.

How Elevated Cortisol Levels Disrupt Sleep

The body thrives on routine, and that includes the sleep cycle. Ideally, cortisol rises in the morning to promote alertness and gradually falls throughout the day, reaching its lowest levels at night so melatonin, the sleep hormone, can take over. But when cortisol remains elevated into the evening, sleep quality suffers.

One of the biggest ways high cortisol interferes with sleep is by disrupting the body’s circadian rhythm. Chronic stress flattens the natural cortisol curve, making it harder to wind down at night. Instead of feeling naturally sleepy, you may feel restless, anxious, or wired, even when physically exhausted. Studies confirm that chronic stress alters cortisol secretion patterns, leading to insomnia and fragmented sleep.

High cortisol also suppresses melatonin production, the hormone responsible for making you feel drowsy. Without enough melatonin, falling asleep becomes a challenge, and even if you do drift off, staying asleep is just as difficult. This is why many people with stress-related insomnia wake up frequently during the night or experience light, unrefreshing sleep.

Another major problem is that cortisol keeps the nervous system in a heightened state of alertness. This makes it difficult for the body to transition into deep, restorative sleep. The deeper stages of sleep are where the body repairs itself, supports brain function, and balances hormones. Without this essential recovery time, you wake up groggy and fatigued, no matter how early you went to bed.

Recognising the Signs of High Cortisol Affecting Sleep

Cortisol dysregulation doesn’t just show up as tiredness. Many people dealing with high cortisol experience difficulty falling asleep, waking up frequently during the night, and feeling wired but exhausted. If you wake up groggy and unrefreshed, struggle with afternoon energy crashes, or experience anxiety and restlessness in the evening, it could be a sign that cortisol is interfering with your sleep cycle.

Studies have shown that people with higher cortisol levels at night are more likely to experience poor sleep quality, increased night-time awakenings, and feelings of fatigue the following day. This means that high cortisol doesn’t just affect sleep—it also impacts mood, productivity, and overall well-being.

Strategies to Balance Cortisol Levels for Better Sleep

The good news is that there are plenty of ways to rebalance cortisol and improve sleep quality. One of the most effective strategies is managing blood sugar levels, as blood sugar fluctuations can trigger cortisol spikes. Recent research found that consuming balanced meals with protein, healthy fats, and fibre helps prevent the blood sugar dips that contribute to cortisol overproduction.

Dietary Approaches

 Magnesium-rich foods such as leafy greens, nuts, and seeds can also help regulate the nervous system, while tryptophan-containing foods like turkey and salmon support melatonin production. Reducing caffeine intake, particularly in the afternoon and evening, can prevent additional cortisol spikes that delay melatonin release.

Lifestyle Modifications

Lifestyle modifications are another essential part of balancing cortisol. Studies show that engaging in gentle movement, such as yoga or walking, reduces cortisol levels without overstimulating the body. 

Establishing a bedtime routine that includes relaxation techniques, such as deep breathing or meditation, signals to the body that it’s time to wind down. Avoiding stimulating activities before bed, such as checking emails, watching intense TV shows, or consuming heavy meals, can help prevent further cortisol spikes.

Environmental Factors

Your sleep environment plays a crucial role as well. Research highlights that exposure to artificial light in the evening suppresses melatonin production and increases cortisol levels. 

Keeping your bedroom cool, dark, and quiet supports melatonin release and improves sleep quality. A consistent sleep schedule is also key—going to bed and waking up at the same time every day helps regulate the body’s internal clock, preventing further disruptions to the cortisol-melatonin cycle.

When to Seek Professional Help

If lifestyle changes aren’t improving sleep disturbances, it may be time to consult a healthcare provider. Chronic high cortisol can contribute to adrenal dysfunction, making it harder for the body to regulate stress and sleep naturally. 

Signs that professional help may be needed include persistent sleep issues despite making lifestyle changes, symptoms of adrenal fatigue such as extreme tiredness and low blood pressure, and chronic stress that affects daily life, mood, and energy levels.

A functional medicine practitioner or endocrinologist can assess cortisol levels through saliva or blood tests and provide personalised recommendations, including adaptogenic herbs, supplements, or specific interventions to support adrenal health. 

Research suggests that adaptogens such as ashwagandha and rhodiola can help regulate cortisol levels and improve resilience to stress, making them beneficial for those experiencing chronic cortisol-related sleep disturbances.