Hyperventilation and Hypoventilation

Written by Jim Folk
Medically reviewed by Marilyn Folk, BScN.
Last updated May 28, 2021

A change in blood oxygen (CO2) level, either too much or too little, can cause many anxiety-like symptoms,[1][2] including:


  • Belching or bloating
  • Chest pain or tightness
  • Dry mouth
  • Faster than normal heartbeat
  • Feeling as if you can't catch your breath
  • Feeling faint, dizzy, weak, or lightheaded
  • Feeling that air is not getting into the lungs
  • Frequent yawn or sighs
  • Headache
  • Increase in feeling anxious
  • Muscle spasms in the hands and feet
  • Not able to think straight
  • Numb, tingly feeling in your hands or feet
  • Numbness and tingling in the arms or around the mouth
  • Numbness or tingling in the fingers
  • Pounding heart
  • Problems sleeping
  • Shortness of breath, or feeling that you can’t get enough air


  • Bluish coloration of the skin caused by lack of oxygen
  • Bluish-colored lips, fingers, or toes
  • Blushing
  • Confusion
  • Daytime drowsiness, sleepiness
  • Delirium
  • Depression
  • Disorientation
  • Dizziness, lightheadedness
  • Fatigue, tiredness
  • Headaches
  • High or low blood pressure
  • Muscle weakness
  • Nausea
  • Rapid heart rate
  • Reduced pupils
  • Seizures
  • Shallow breathing
  • Shortness of breath
  • Slow and shallow breathing
  • Swelling of the ankles
  • Tremors
  • Vomiting
  • Waking up from sleep unrested
  • Waking up many times at night

As hyper and hypoventilation relates to anxiety, when you are stressed, anxious, or think you are in danger, stress hormones are released into the bloodstream. Stress hormones change breathing patterns from slow, deeper breaths, to either rapid, deeper breaths (hyperventilation), or to rapid, shallow breaths (Tachypnea).

When your breathing changes to either of these patterns, carbon dioxide (CO2) levels in the bloodstream decrease. Low levels of CO2 can cause lightheadedness, dizziness, wooziness, and feeling faint, which can trigger an instinctive fear reaction.

This fear reaction can be sufficient to cause an involuntary high degree stress response similar to that of a panic attack.

Moreover, some people hold their breath or under breathe when they are stressed or anxious, causing hypoventilation (not enough oxygen). Not enough oxygen increases CO2 in the blood.

An increase in CO2 can also cause lightheadedness, dizziness, wooziness, and feeling faint, which can also be sufficient to cause an involuntary high degree stress response.

Both hyperventilation and hypoventilation can cause many anxiety-like symptoms, including involuntary panic attacks.[3]

Changing your breathing to a normal pattern can restore healthy CO2, eliminating symptoms of hyper or hypoventilation.

The combination of good self-help information and working with an experienced anxiety disorder therapist, coach, or counselor is the most effective way to address anxiety and its many symptoms. Until the core causes of anxiety are addressed – which we call the underlying factors of anxiety – a struggle with anxiety unwellness can return again and again. Dealing with the underlying factors of anxiety is the best way to address problematic anxiety.

Additional Resources

Return to our anxiety disorders signs and symptoms page.

anxietycentre.com: Information, support, and therapy for anxiety disorder and its symptoms, including Hyperventilation and Hypoventilation.


1. “Hyperventilation.” MedlinePlus, 28 June 2018, https://medlineplus.gov/ency/article/003071.htm

2. “Respiratory depression: Causes, symptoms, and treatment.” Medical News Today, 21 Aug. 2017, https://www.medicalnewstoday.com/articles/319030.php

3. Meuret, Alicia E., and Thomas Ritz. “Hyperventilation in Panic Disorder and Asthma: Empirical Evidence and Clinical Strategies.” NCBI PubMed, U.S. National Library of Medicine, Oct. 2010, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2937087