Hyperarousal, Sleep, and Mindfulness
What is ‘Hyperarousal’?
Hyperarousal is a common mind-body state — so common that people often experience hyperarousal as ‘normal’! But science shows us that habitual hyperarousal is unhealthy for mind and body.
Hyperarousal refers to stress reactivity — especially the physical side of stress reactivity. When people get stressed, their body goes into hyperarousal.
The body is ‘on alert’ — with muscle tension, changes in blood pressure and heart activation patterns, characteristic effects on blood circulation, digestion, altered levels of hormones & ‘cytokines’, other changes in immune function, etc.
Surprisingly, people often don’t notice their physical feelings of hyperarousal.
That’s because they pay more attention to their psychological stress — their stressed thinking, the ‘story’ of their stress, what’s going on in their mind. But they overlook the physical side of their stress — they ignore hyperarousal.
Hyperarousal and Sleep
Most sleep scientists have considered hyperarousal to be a major contributor to sleep problems.
A 2018 scientific paper tells us: “Hyperarousal is a key component in all modern etiological models of insomnia disorder... [The scientific literature] suggests that over-active neurobiological and psychological systems contribute to difficulty sleeping.” 
During natural healthy sleep, your body follows with your brain’s rhythmic activation pattern of sleep all through the night, until eventually you awaken back into consciousness in the morning.
But with hyperarousal, the brain’s natural rhythm of sleep is disturbed. The body isn't able to relax into deep sleep. And sleep is often fragmented, shallow, hard to stay asleep.
Scientists speculate that some people spend most of their day in hyperarousal. They just don’t notice it — until, at night, they try to sleep.
And many people get especially reactive to stressful thinking later in the day. This extra stress-reactivity heightens their hyperarousal, further worsening their sleep disturbance.
Mindfulness and Hyperarousal
More than two decades of research show that programs of MBSR (Mindfulness-Based Stress Reduction) help people reduce chronic stress.
So, it’s not surprising that mindfulness-based programs are well-known to help people sleep. One study even showed that a program of MBSR could be as effective as the sleep medication, Lunesta — but without side-effects! 
Various other studies have shown that mindfulness-based programs improve sleep , including an MBSR program that helped the sleep of participants older than 75 , and a 2022 Iranian study in which MBSR improved sleep quality for postmenopausal women. 
And I've seen this too. During my 20+ years teaching MBSR, countless patients told me how they started sleeping better after beginning the program's daily routine of mindfulness practices.
Note: Mindfulness isn't a tool to make yourself immediately fall asleep -- its not like a 'sleeping pill' of mindfulness! Instead, people find that regular daily mindfulness (especially mindful physical awareness) gradually reduces habitual hyperarousal. They just start sleeping better.
Problems don't disturb sleep!
When people consider their stress, they often think about their stress-filled thoughts, the 'story' of their problems. For them, this is 'stress'.
But it's not the thoughts that disturb sleep. It's the hyperarousal! Yes, people might have problems, but still they can sleep well -- if they reduce hyperarousal.
To your natural happiness!
1. Hyperarousal and sleep reactivity in insomnia: current insights. David A Kalmbach, et al. Dove Press Nature and Science of Sleep 2018.10
2. Mindfulness-based stress reduction vs. pharmacotherapy for primary chronic insomnia: a pilot randomized controlled clinical trial. Cynthia R. Gross, et al. Explore (NY). 2011
3. A randomized controlled trial of mindfulness meditation for chronic insomnia. Ong JC, et al. Sleep. 2014
4. Mindfulness-based stress reduction for chronic insomnia in adults older than 75 years: a randomized, controlled, single-blind clinical trial. Zhang JX, et al. Explore (New York, N.Y.). 2015, May-Jun
5. Mindfulness-based stress reduction group training improves sleep quality in postmenopausal women. Samaneh Darehzereshki, et al. BMC Psychiatry (2022)