If you have anxiety, you probably have sleep problems.
If you have sleep problems, your anxiety is almost certainly worse because of them.
This isn't a coincidence. Sleep and anxiety have a bidirectional relationship: each one directly worsens the other, and they reinforce each other in ways that are hard to untangle without understanding the mechanism.
What Anxiety Does to Sleep
When you're anxious, your body maintains elevated cortisol and adrenaline levels. These are the stress hormones your nervous system uses to keep you alert in threatening situations.
The problem: sleep requires the opposite state. Your body needs to lower its core temperature, reduce heart rate, and shift out of threat-detection mode. Elevated stress hormones prevent all three.
This is why anxious people often describe lying in bed exhausted but unable to sleep. The body is tired, but the nervous system hasn't received the signal that it's safe to switch off.
The result is usually one of two patterns:
Difficulty falling asleep: Racing thoughts, hyperawareness of physical sensations, inability to stay still. The mind keeps generating problems to solve at exactly the moment it needs to let go.
Early waking: Falling asleep but waking at 3 or 4am with a jolt of anxiety. Cortisol naturally rises in the early morning to prepare the body for the day, but in anxious people it often spikes too early and too sharply.
What Poor Sleep Does to Anxiety
A single night of poor sleep increases emotional reactivity by up to 60%, according to a 2019 study from UC Berkeley. The amygdala, the brain's threat-detection centre, becomes significantly more responsive after sleep deprivation.
More practically: poor sleep reduces the functioning of your prefrontal cortex, the part of your brain that provides rational perspective on anxious thoughts. Without it, catastrophic thinking is harder to challenge. The automatic thoughts that CBT teaches you to question become much more convincing when you're sleep-deprived.
This is why anxious people often notice their anxiety is dramatically worse when they're tired. It's not in their heads. The neurological capacity to manage anxiety is genuinely reduced.
The Loop
Anxiety causes poor sleep. Poor sleep increases anxiety. Increased anxiety causes worse sleep. This loop is self-sustaining, which is why people who develop anxiety-related insomnia often stay in it for months or years without understanding why.
Tracking your sleep quality alongside your anxiety levels is one of the most useful things you can do. Patterns that aren't obvious day-to-day become very clear over weeks of data.
Breaking the Loop
Address the Anxiety First
Most sleep hygiene advice treats insomnia as a sleep problem. In anxious people, it's usually an anxiety problem that shows up at night. Tackling the sleep symptoms directly while anxiety remains untreated produces limited results.
This means: journaling before bed to process the day's anxious thoughts rather than bringing them into the bedroom, using the structured CBT approach to discharge the most active worries before you try to sleep.
BrainHey's evening journaling flow takes about 5 minutes and is specifically designed to help you close open mental loops before bed.
The 90-Minute Rule
Your nervous system needs about 90 minutes to downregulate from stimulation to sleep readiness. Working, watching intense content, or having stressful conversations right up until bedtime leaves your cortisol elevated when you try to sleep.
Build a 90-minute wind-down. This doesn't need to be elaborate: dimmer lighting, lower stimulation, no work. Your nervous system needs a transition period, not an on/off switch.
Don't Use the Bedroom as an Anxiety Arena
If you regularly lie awake anxious in bed, your brain begins to associate the bedroom itself with the anxious state. This is called conditioned arousal, and it's why some people with severe insomnia feel tired everywhere except their own bed.
If you've been lying awake for more than 20 minutes, get up. Do something calm in low light. Return when you feel sleepy. This breaks the conditioned association over time.
Track the Relationship
The most underutilised insight for anxious sleepers is simply data. Most people have no idea which days they sleep well or what's different about them.
When you start tracking sleep quality alongside mood, anxiety levels, and daily events, patterns emerge: the evening activities that help, the thought patterns that correlate with 3am waking, the circumstances that reliably produce good nights.
BrainHey tracks sleep quality as part of every journal entry and surfaces the correlations automatically, so you can see exactly what's affecting your sleep without having to maintain a separate log.
The sleep-anxiety loop feels impossible to break because attacking one side without understanding the other produces limited results. Treat them together, with data, and the pattern becomes much more manageable.