How to Fall Asleep When You Can’t Switch Off
You’re exhausted. Your body feels heavy. And your mind won’t stop. You replay conversations. Problem solve for tomorrow. Revisit old worries. If you struggle with racing thoughts at night, you’re really not alone.
But how do you actually fall asleep when your brain won’t cooperate? The answer isn’t willpower. It’s physiology (shocker).
Why you’re lying awake even when you’re tired
Sleep latency (the time it takes to fall asleep) is influenced by more than just physical fatigue. It’s shaped by your cognitive load and your nervous system state. In simple terms, great sleep doesn’t happen just because you’re tired. It happens when your brain feels safe enough to power down.
Research on insomnia shows strong links to cognitive hyperarousal (a state where the brain remains overly alert at night). Instead of slowing down, it stays active, problem-solving and processing. This heightened mental activity is what often delays sleep and/or contributes to fragmented sleep.
So even if you have a consistent bedtime routine and feel physically exhausted, unprocessed mental load can keep you awake. Sleep doesn’t begin when you’re tired. It begins when your brain is ready to let go.
Racing thoughts at night are a daytime problem
Throughout the day, your brain absorbs an enormous amount of stimulation:
Notifications
Screen time
Decision-making
Emotional processing
Work stress
Social interactions
Even when these experiences are no longer front of mind, they still activate your sympathetic nervous system — the system responsible for alertness and survival. For many people, bedtime is the first quiet moment of the day. And in that quiet, the brain finally starts processing everything it didn’t have time to process earlier.
Research suggests that is associated with increased metabolic and cortical activity at night — meaning your brain is still highly active when it should be transitioning into rest. When the nervous system remains alert, melatonin production can be delayed, and your brain stays in “problem-solving mode” instead of recovery mode.
That “tired but wired” feeling? It’s your nervous system struggling to shift gears.
Why constant stimulation makes it hard to fall asleep
Modern life rarely allows true decompression. Common contributors to racing thoughts at night include:
Blue light exposure before bed
Emotional conversations close to bedtime
High cognitive demand throughout the day
Environmental noise
Decision fatigue
When stimulation never fully stops, your body never receives a clear signal that it’s safe to rest. So we take the day to bed with us.
Sleep starts with safety
Sleep is not something you force. It’s something your body allows. For sleep to begin, the parasympathetic nervous system, often called “rest and digest”, needs to take over. This shift reduces heart rate, lowers stress hormones, and prepares the brain for deeper rest.
Think of sleep as a state your body enters when it no longer needs to stay alert. The real question isn’t just how to fall asleep. It’s how to feel safe enough for your nervous system to do so.
How to fall asleep
If racing thoughts at night are driven by overstimulation, the solution is gentle downregulation — reducing cognitive and sensory input before bed.
1. Reduce Cognitive Input Before Bed
Write down tomorrow’s to-do list to offload mental clutter
Avoid screens at least 60 minutes before sleep
Use softer, warmer lighting in the evening
2. Signal Safety to the Brain
Practice slow breathing (try inhaling for 4, exhaling for 6)
Take a warm shower to support heat regulation
Train your body & mind with consistent bed and wake up times
3. Reduce Sensory Stimulation
Keep the room dark and cool
Minimise noise
Allow physical stillness before sleep
Research suggests that lowering external stimuli and reducing cognitive demand may help decrease hyperarousal, allowing the nervous system to shift into a sleep-ready state. In other words: the less your brain needs to monitor, process or react to, the easier it becomes to fall asleep.
The Role of Sensory Reduction in Sleep Readiness
Sensory reduction and parasympathetic activation environments can support the transition from alertness to rest. When external input decreases — light, noise, temperature fluctuations, mental stimulation — the brain has fewer reasons to stay vigilant. This downshift supports melatonin release and reduces sleep latency. Experiences designed to calm the nervous system and remove stimulation may help the body transition into sleep mode more effectively.
If you can’t switch off at night, it’s not a personal failure. It’s a nervous system that hasn’t been given permission to slow down. Sleep begins when safety replaces stimulation.
Creating environments that reduce sensory input and support parasympathetic activation can help your body fall asleep more naturally — instead of fighting for it. And if your mind struggles to power down, it may be worth exploring experiences specifically designed to calm the nervous system before bedtime.
Emerging research continues to explore the connection between cognitive arousal, nervous system activation, and sleep onset.
If you’d like to explore the science further, here are a few foundational studies:
Riemann, D., et al. (2010). The hyperarousal model of insomnia: A review of evidence. Sleep Medicine Reviews.
– Explores how cognitive and physiological hyperarousal contribute to difficulty falling asleep.Kay, D. B., & Buysse, D. J. (2017). Hyperarousal and beyond: New insights into insomnia mechanisms. Current Sleep Medicine Reports.
– Discusses how increased cortical and metabolic activity may delay sleep onset.Perlis, M. L., et al. (2001). Beta/Gamma EEG activity in patients with primary insomnia. Sleep.
– Demonstrates elevated brain activity in individuals struggling to fall asleep.Bonnet, M. H., & Arand, D. L. (2010). Hyperarousal and insomnia. Sleep Medicine Reviews.
– Examines the relationship between stress activation and prolonged sleep latency.
