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Breathing and ventilation

Hypoventilation

Breathing that is too shallow or too slow to clear enough carbon dioxide, often first at night.

What it means

Breathing does two jobs: bringing oxygen in and carrying carbon dioxide out. When the muscles weaken, the second job slips first, and it slips first during sleep. Morning headaches, heavy sleepiness and unrefreshing nights are the usual signs.

Why you might hear it

  • It is the reason an overnight test may be arranged.
  • It is often the finding that leads to NIV being offered.

People who may help

Where Compass goes into this

About this explanation

These are plain explanations of words you may come across, not advice about your own situation. Where a word matters to a decision, the question pages go into it properly, and your own team is the place to take it.