Published 14 December 2023

Why Can’t I Sleep?

This article explores the scientific underpinnings of insomnia, offering solutions to help you out if you regularly can’t sleep.

The inability to fall asleep is a struggle known by many. Even when you feel tired, you sometimes still can’t get the much needed rest. However, if this is a regular battle, you’re likely dealing with an experience aptly termed insomnia. The article dives into the reasons behind the inability to fall asleep, which involve physical, mental, and environmental factors.

Brain chemistry

Inside our brains, chemicals play a key role in sleepiness and wakefulness. A neurotransmitter called adenosine acts as a sleepiness signal, making us feel sleepy as it accumulates throughout the day. Sometimes, this process doesn’t work as it should, which can lead to feeling tired but not necessarily sleepy. Sometimes, this process doesn’t work as it should, which can lead to feeling tired but not necessarily sleepy.

Another neurotransmitter, GABA, helps quiet down brain activity so we can sleep. Problems with this “brake system” might mean you can’t fall asleep.

Cortical hyperarousal is a state where the outer layer of the brain, known as the cerebral cortex, is excessively alert or active. This heightened brain activity can make it difficult for a person to relax, fall asleep, or maintain restful sleep. Or, in simpler terms, cortical hyperarousal means your brain is overly active when you should be getting ready to sleep.

The mind’s role

Our thoughts and emotions can also interfere with sleep. Stress, anxiety, or simply having a lot on our minds can keep our thoughts racing, making it hard to relax into sleep even if our body is tired.

When we’re under chronic stress, our body can stay in a state of high alert, making it tough to wind down and fall asleep. Simply overthinking, like fixating on your inability to sleep, can make it difficult to fall asleep. The very act of struggling to fall asleep can create a cognitive loop that associates your bed with wakefulness. The phenomenon of conditioned arousal, where the mind associates the bed with wakefulness, makes it increasingly difficult to fall asleep.

Internal body clock

The body’s internal clock—the circadian rhythm—plays a pivotal role in sleep regulation, telling us when to feel sleepy or awake.

Time confusion, caused by shift work or irregular sleep schedules, can confuse our body clock. This leads to feeling tired at the wrong times or being awake when we should be asleep.

Alternatively, a disrupted circadian rhythm could be due to artificial lighting and digital screens. When our internal clock doesn’t match external cues, it can cause a circadian rhythm disorder, which is linked to insomnia.

The nocturnal secretion of melatonin, a hormone that heralds the onset of sleep, can be susceptible to disruption. Sleep schedule changes, lack of light exposure, and too much screen time can all affect melatonin release.

Lifestyle and environment

Our habits and experiences can also affect our ability to sleep and continuously not getting enough sleep can throw off our body’s balance between sleepiness and wakefulness.

A sedentary lifestyle, devoid of physical activity’s vigor, can lead to a lessened sleep drive. The absence of bodily exertion can dilute the physiological need for restful slumber.

Caffeine also has a lingering effect on our bodies. After drinking coffee, the wakeful effects of caffeine can linger, making it harder to fall asleep even when we’re physically tired.

What to do when you can’t sleep

Minor changes can make a big difference in promoting restful sleep. Start by optimizing your sleep environment—keep your bedroom dark, quiet, and cool. You should also establish a consistent sleep schedule, limiting screen time and caffeine intake before heading to bed.

What you do during the day can also impact how well you sleep at night. Combat overactive brain activity with relaxation techniques like deep breathing, yoga, or meditation. Stay out of bed during the day to prevent associating it with being awake, and get 30 minutes of sunlight outside. This will help align your circadian rhythm, allowing you to doze off when you usually can’t fall asleep.


The inability to sleep is like a puzzle with many pieces, influenced by brain chemistry, our thoughts, our body’s clock, and even our habits. The scientific exploration of this puzzle reveals the complexity of sleep, and how the pieces don’t always fit perfectly together. Solutions for better sleep may require a combination of strategies to align these factors and create a better path for restful nights.

Note: While this article delves into the scientific explanations and solutions for insomnia, it is essential to recognize that insomnia is a complex and multifactorial condition. Consulting healthcare professionals or specialists for personalized guidance and treatment is recommended for individuals struggling with chronic sleep disturbances.


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