RangeMedical
SIDE EFFECT MANAGEMENT GUIDE

HBOT
Side effects

Every side effect explained in plain English. What it feels like, why it happens, and exactly what to do about it — step by step.

THE BIG PICTURE

What to Expect

HBOT puts you in a pressurized chamber with pure oxygen at 2.0 ATA. The increased pressure and oxygen concentration is what makes it therapeutic — but it also means your body experiences conditions it is not used to.

Most side effects are mild, happen during the session, and resolve quickly. Your technician monitors you throughout.

1
Ear Pressure

Pressure in your ears during pressurization.

2
Sinus Pressure

Pain in forehead, cheeks, or behind eyes.

3
Vision Changes

Temporary shift in near/distance vision.

4
Fatigue

Feeling tired after sessions as your body heals.

5
Lightheadedness

Brief dizziness when the chamber depressurizes.

6
Mild Headache

Dull headache during or after a session.

7
Claustrophobia

Anxiety or panic inside the chamber.

8
Tooth Pain

Sharp tooth pain during pressure changes.

1
MOST COMMON

Ear Pressure & Discomfort

Nearly everyone feels this, especially during their first few sessions

What It Feels Like

Pressure in your ears during the first few minutes as the chamber pressurizes. Like descending in an airplane, but more gradual. Can range from mild pressure to actual pain if you do not equalize.

Why It Happens

As pressure increases inside the chamber, the air pressure pushes on your eardrum from outside. The Eustachian tube — connecting your middle ear to your throat — needs to let air in to equalize the pressure on both sides of the eardrum.

What to Do

Try First
Swallow frequently during pressurization. This opens your Eustachian tubes naturally.
Yawn or wiggle your jaw. Both help open the passages that equalize ear pressure.
Valsalva maneuver: Gently pinch your nose and blow. You should feel a soft pop as your ears equalize. Do this repeatedly during pressurization.
Chew gum during the session. The chewing motion keeps your Eustachian tubes active.
Tell your technician to slow the pressurization if you need more time to equalize. The rate can always be adjusted.
If It Hurts
Tell your technician immediately. They will stop or slow pressurization right away. Never "push through" ear pain.
The pressurization rate can always be adjusted. There is no fixed speed — your comfort determines the pace.
Do Not Do HBOT If
You have an active ear infection, severe congestion, or recent ear surgery. Tell us before your session if you are congested or have a cold.
Gets Easier Every Session

Your ears learn to equalize faster with practice. Most people have zero ear issues by their 3rd or 4th session.

2
COMMON

Sinus Pressure

Common, especially if you have any congestion

What It Feels Like

Pressure or pain in your forehead, cheeks, or behind your eyes during pressurization. Like a sinus headache.

Why It Happens

Same mechanism as ear pressure — the sinuses are air-filled cavities in your skull. If they cannot equalize pressure (especially if you have any congestion), the pressure difference causes pain.

What to Do

Try First
Take a decongestant (pseudoephedrine/Sudafed) 30-60 minutes before your session. This opens your sinus passages so they can equalize pressure.
Use nasal spray (oxymetazoline/Afrin) 15 minutes before your session. This directly opens your nasal and sinus passages.
If It Hurts
Tell your technician to slow or pause pressurization. Like ear equalization, sinus equalization works better with more time.
Do Not Do HBOT If
You have a sinus infection or severe nasal congestion. Reschedule until it clears. Trying to pressurize with blocked sinuses is painful and counterproductive.
Preventable

A pre-session decongestant eliminates this for the vast majority of people. Once you know your sinuses need the prep, it becomes routine.

3
COMMON

Temporary Vision Changes

Common with repeated sessions, usually noticed after 10+ sessions

What It Feels Like

After multiple sessions (usually 10+), you may notice your near vision gets slightly better and distance vision gets slightly blurrier. Like a mild prescription change.

Why It Happens

Prolonged oxygen exposure temporarily changes the shape of your eye lens — it becomes slightly more rounded. This shifts your focal point. It is a well-documented, reversible effect of hyperbaric oxygen.

What to Know

This Is Temporary
Vision reverses within 2-8 weeks after completing your HBOT series. This is documented in every HBOT textbook.
Do NOT get a new eyeglass prescription during or immediately after an HBOT protocol. Wait until your vision returns to baseline.
Call Us If
Sudden vision loss, severe blurriness, flashing lights, or new floaters. These are not normal HBOT effects and need immediate evaluation.
100% Reversible

Vision returns to baseline after completing the HBOT series. This is documented in every HBOT textbook and is not a concern.

4
COMMON

Fatigue After Sessions

Common, especially in the first 5-10 sessions

What It Feels Like

Feeling tired or unusually sleepy after your session, sometimes for the rest of the day. Some describe it as a "good tired" like after a workout.

Why It Happens

Your body is doing significant repair work with all that extra oxygen. Stem cell mobilization, angiogenesis (new blood vessel growth), and inflammation reduction all take energy. Your body is using the oxygen to heal — and that healing process is physically demanding.

What to Do

Try First
Plan sessions so you can rest afterward if needed. Especially for your first few sessions, do not schedule anything demanding right after.
Eat a good meal before your session. Going in on an empty stomach makes fatigue worse.
Stay hydrated. Dehydration amplifies fatigue. Drink water before and after your session.
Light activity is fine but skip intense workouts on HBOT days. Let your body use that energy for healing.
Your Body Is Healing

Fatigue is actually a positive indicator that the therapy is activating repair processes. Most people feel increasingly energized as their protocol progresses.

5
LESS COMMON

Lightheadedness

Less common — usually brief and happens at the end of a session

What It Feels Like

Brief feeling of dizziness or lightheadedness when the chamber depressurizes at the end of the session, or when standing up to exit. Similar to standing up too quickly.

Why It Happens

The shift from high-pressure oxygen back to normal atmospheric pressure briefly affects blood flow and oxygen delivery to your brain. Your body needs a moment to recalibrate.

What to Do

Try First
Sit up slowly when the chamber opens. Take a moment before standing.
Drink water and eat something after your session. This helps stabilize blood pressure and blood sugar.
If it persists, stay seated and tell your technician. There is no rush to leave the chamber area.
Brief and Normal

Lasts less than a minute for most people. If it persists, stay seated and tell your technician.

6
LESS COMMON

Mild Headache

Less common — usually related to sinus pressure, dehydration, or skipping meals

What It Feels Like

Dull headache during or after a session. Not severe but noticeable.

Why It Happens

Can be from sinus pressure (see above), mild oxygen sensitivity, or dehydration. Skipping meals before sessions makes this more likely.

What to Do

Try First
Eat before your session. Going in on an empty stomach is a common headache trigger.
Stay hydrated. Dehydration is the other common trigger. Drink water before and during your session.
Pre-treat with a decongestant if sinuses are the cause. See the Sinus Pressure section above.
OTC pain reliever (ibuprofen or acetaminophen) if needed after your session.
If Recurring
Contact us. We may adjust session duration or pressure to find a more comfortable protocol for you.
Usually Preventable

Hydration + food + sinus prep eliminates this for most people. Once you identify your trigger, headaches rarely come back.

7
LESS COMMON

Claustrophobia

Less common but important — some people feel anxious in enclosed spaces

What It Feels Like

Feeling anxious, trapped, or panicky inside the chamber. May feel worse during pressurization when you cannot immediately exit.

Why It Happens

The chamber is an enclosed space. Some people have a natural anxiety response to enclosed environments. The inability to immediately leave adds to the feeling.

What to Do

Try First
Tour the chamber before your first session. Seeing it and understanding how it works reduces anxiety significantly.
Bring your phone or a tablet to watch during the session. Distraction is one of the most effective tools for managing claustrophobia.
Practice deep breathing. Slow, controlled breaths calm your nervous system. Breathe in for 4 counts, hold for 4, out for 4.
Know that you CAN communicate with your technician at all times and the session CAN be stopped. The chamber has a clear window.
If Significant
We can do a short "practice session" at lower pressure. This lets you get comfortable with the chamber without committing to a full 60-minute session.
Some patients benefit from a mild anti-anxiety medication before their first few sessions. Ask your provider if this is right for you.
You Are Always in Control

You can communicate with your technician at any time. The session can be stopped and the chamber depressurized at your request. You are never locked in.

8
RARE

Tooth Pain

Rare — only happens if you have an existing dental issue

What It Feels Like

Sharp pain in a tooth during pressurization or depressurization. It can be sudden and intense.

Why It Happens

If you have a cavity, cracked tooth, or recent dental work with an air pocket, the pressure change can push on that trapped air and cause pain. Same mechanism as "barodontalgia" that scuba divers experience.

What to Do

What To Do
Tell your technician immediately. They can adjust the pressurization rate or stop the session if needed.
See a dentist before continuing HBOT sessions to address the underlying dental issue causing the pain.
Signals a Dental Issue

HBOT did not cause the problem, it revealed it. Fixing the dental issue resolves the pain completely.

IMPORTANT

When to Contact Us

Most side effects can be managed with the steps in this guide. But some situations need our help right away.

Call Us Right Away

  • Ear pain that does not resolve after the session
  • Sudden vision changes (not the gradual kind)
  • Persistent severe headache
  • Chest pain or difficulty breathing
  • Any seizure-like symptoms (extremely rare at 2.0 ATA but worth knowing)

Schedule a Check-In

  • Fatigue that is affecting your daily life
  • Recurring headaches after sessions
  • Anxiety that is preventing you from completing sessions
  • Questions about your protocol or timeline

Important: This guide is for Range Medical patients receiving hyperbaric oxygen therapy. Sessions at 2.0 ATA, 60 minutes. Not a substitute for personalized medical advice. All sessions are monitored by trained technicians. Individual responses vary.

Questions? We Are Here.

Whether you need a session adjustment, have concerns about a side effect, or just want to talk through what you are experiencing — our team can help.

Call (949) 997-3988Text Us

1901 Westcliff Dr. Suite 10, Newport Beach, CA 92660