Why Fibromyalgia Causes Pain, Why It Worsens at Night, and How Poor Sleep Fuels Brain Fog

Fibromyalgia pain stems from altered nervous‑system processing causing varied sensations that often worsen at night; learn why sleep breaks down, how brain fog follows, and five practical tips to sleep better.

What causes the pain in fibromyalgia

Fibromyalgia is not simply damaged tissue; it reflects changes in how the brain and spinal cord process signals. This central sensitisation means normal touch or movement can be amplified into pain. Neurochemical differences (for example altered serotonin and substance P) and impaired pain‑inhibition pathways contribute to persistent, widespread pain.

How pain feels and where it appears

• Types of sensations: Dull aching, burning, sharp/stabbing, throbbing, electric‑shock sensations, pins and needles and numbness. These can vary in intensity and quality from hour to hour.
• Typical locations: Widespread musculoskeletal pain is common — neck, shoulders, lower back, hips and limbs are frequent sites; headaches, facial or jaw (TMJ) pain and chest wall discomfort also occur. 
• Sensitivity features: Allodynia (pain from light touch) and hyperalgesia (exaggerated pain from painful stimuli) are common; temperature changes and pressure points may trigger burning or stiffness. 

Why symptoms often worsen at night and disturb sleep

• Hormonal and circadian shifts: Night‑time falls in cortisol and altered melatonin rhythms can reduce the body’s natural pain‑modulating effects, making sensations feel stronger after dark.
• Reduced distraction: With fewer daytime activities, attention often turns to bodily sensations, increasing perceived pain.
• Disrupted sleep architecture: People with fibromyalgia commonly have reduced deep (slow‑wave) sleep, which prevents muscle relaxation and restorative processes; this both increases pain and makes it harder to stay asleep. 

Sleep deprivation, brain fog and the vicious cycle

Poor sleep increases pain sensitivity and weakens descending pain control, so one bad night often leads to worse pain the next day. Chronic sleep loss also impairs cognition — memory, attention and processing speed — commonly called “fibro‑fog.” Pain, fatigue and cognitive problems then feed back to worsen sleep, creating a self‑reinforcing cycle. 

Encouragement and five practical steps for better nights

You are not defined by your symptoms — small, consistent changes can improve comfort and sleep.

1. Optimise the bedroom: keep it cool, dark and quiet; use breathable bedding to reduce night‑time discomfort.
2. Gentle wind‑down routine: dim lights, avoid screens 30–60 minutes before bed and practise slow breathing.
3. Positional supports: use pillows under knees or at the neck to relieve pressure points and reduce muscle tension.
4. Limit stimulants and heavy evening meals: avoid caffeine and large meals after mid‑afternoon; choose light, low‑fat snacks if needed.
5. Bedtime relaxation: short body‑scan or progressive muscle relaxation in bed to shift attention away from pain and encourage sleep onset.