HBOT side effects and safety

2 min read

Hyperbaric oxygen therapy has a long safety record when it's done with proper screening and trained staff. Like any treatment, though, it has side effects worth knowing about.

Common and usually mild

• Ear pressure and discomfort. By far the most common issue. Learning to equalize prevents most problems. See Ear pressure in the chamber.
• Sinus pressure. Similar cause; much more likely if you're congested.
• Tiredness or lightheadedness after a session.
• Feeling warm while the chamber pressurizes, or cool as it depressurizes.

Less common

• Middle ear barotrauma. Injury from pressure that isn't equalized, ranging from bruising of the eardrum to, rarely, a perforation. Stopping when you feel pain prevents most cases.
• Temporary vision changes. Some people on long courses of HBOT, often dozens of sessions, become slightly more nearsighted. This usually reverses over weeks to months after treatment ends.
• Claustrophobia. Anxiety in enclosed spaces. Clear or seated chambers often help.

Rare but serious

• Oxygen toxicity seizures. High oxygen levels at pressure can, rarely, trigger a seizure. It's uncommon, mostly linked to higher medical pressures, and usually stops once the person breathes normal air. Risk is higher with fever, a seizure disorder or certain medications, which is why screening matters.
• Lung barotrauma. Lung injury from pressure changes, extremely rare in properly screened people.
• Fire. Oxygen-rich environments make fires more dangerous, which is why chambers have strict rules about what you can bring in. See Fire safety in hyperbaric chambers.

How good providers keep you safe

• A full health screening before your first session, updated when your health changes
• Trained staff present for every session
• Slow, controlled pressure changes, with the option to pause
• Strict rules on clothing, products and items in the chamber
• Regular equipment maintenance

After your session

Contact your doctor if you have ear pain that doesn't settle, hearing changes, ongoing dizziness, chest pain or shortness of breath. For anything severe, call 911.

Read Who should not do HBOT before starting.