TL;DR: A typical hyperbaric oxygen therapy (HBOT) session in Canada lasts 60 to 120 minutes. You breathe 100% oxygen inside a pressurised chamber at 1.5 to 3.0 atmospheres absolute (ATA). The most common side effects – ear pressure and temporary vision changes – are mild and resolve on their own. This guide walks you through every step, from preparation to recovery.
Hyperbaric oxygen therapy is a non-invasive medical treatment used in hospitals and accredited clinics across Canada. If your physician has referred you for HBOT, you may be wondering what the experience actually involves. This step-by-step guide from Canada Hyperbarics explains exactly what happens before, during, and after your treatment session so you can arrive informed and confident.
Estimated reading time: 7 minutes
What Is Hyperbaric Oxygen Therapy?
Hyperbaric oxygen therapy (HBOT) is a medical treatment in which you breathe pure oxygen inside a pressurised chamber. The pressure inside the chamber is raised to between 1.5 and 3.0 atmospheres absolute (ATA) – roughly 1.5 to 3 times normal sea-level air pressure. This allows your lungs to absorb significantly more oxygen than they would under normal conditions.
The increased oxygen dissolves into your blood plasma and reaches tissues throughout your body, promoting healing, reducing inflammation, and fighting certain infections. Health Canada recognises HBOT as a treatment for 14 approved indications, including non-healing wounds, radiation injury, carbon monoxide poisoning, and decompression sickness.
How Do You Prepare for Your First HBOT Session?
Preparation is straightforward, but following these steps helps ensure a safe and comfortable experience.
- Get a physician referral. In Canada, HBOT requires a referral from a qualified physician. Your referring doctor will assess whether HBOT is appropriate for your condition and order the treatment. Visit the Canada Hyperbarics clinic directory to find an accredited facility near you.
- Complete a medical screening. The hyperbaric clinic will review your medical history, current medications, and any implanted medical devices. Certain conditions – such as untreated pneumothorax or specific types of chemotherapy – may affect your eligibility.
- Wear appropriate clothing. You will be asked to wear 100% cotton clothing or a hospital-provided cotton gown. Synthetic fabrics, jewellery, watches, hearing aids, and electronic devices are not permitted inside the chamber for safety reasons.
- Avoid certain products. On treatment days, do not use perfume, cologne, hairspray, deodorant, nail polish, or petroleum-based skin products. These items may pose a fire risk in the oxygen-enriched environment.
According to a 2026 phenomenological study published in Nursing Reports, patients who received clear information about procedures and expectations before their first session reported lower anxiety and greater satisfaction with their overall treatment experience (Vila-Vidal et al., 2026).
What Happens When You Arrive at a Hyperbaric Clinic?
When you arrive for your appointment, a trained hyperbaric technician or nurse will guide you through the process. Here is what to expect:
- Vital signs check. Staff will measure your blood pressure, heart rate, and blood oxygen levels before each session.
- Safety briefing. On your first visit, you will receive a full orientation covering chamber operation, ear-clearing techniques, and what to do if you feel uncomfortable during treatment.
- Personal items storage. You will store all personal belongings in a locker outside the treatment area.
- Blood sugar check (if applicable). If you have diabetes, your blood glucose may be tested before entering the chamber to prevent hypoglycaemia during treatment.
What Does a Hyperbaric Treatment Session Feel Like?
Understanding what happens inside the chamber can ease any nervousness. Here is a step-by-step breakdown of a typical session:
Step 1: Entering the chamber
You will either lie down in a monoplace chamber (a single-person clear acrylic tube) or sit in a multiplace chamber (a larger room-sized unit that treats several patients at once). In a multiplace chamber, you breathe oxygen through a hood or mask. In a monoplace chamber, the entire unit is pressurised with pure oxygen. Learn more about the differences between chamber types.
Step 2: Pressurisation (compression)
The chamber pressure increases gradually over 10 to 15 minutes. During this phase, you will feel pressure in your ears – similar to the sensation during aeroplane descent. Staff will teach you techniques to equalise the pressure, such as swallowing, yawning, or gently pinching your nose and blowing. According to research published in PubMed, ear pressure is the most commonly reported sensation during HBOT and is generally mild (Curtis et al., 2021).
Step 3: Treatment at pressure
Once the chamber reaches the prescribed pressure (typically 2.0 to 2.4 ATA), you simply breathe normally. This phase lasts 60 to 90 minutes depending on your treatment protocol. During this time, you can:
- Rest or sleep
- Watch television or a film (many clinics provide screens)
- Listen to music
- Read (paper materials only – no electronics)
Research from Toronto General Hospital found that patients receiving HBOT at 2.0 ATA for 90-minute sessions tolerated the treatment well, with most reporting progressive comfort over successive sessions (Curtis et al., 2021).
Step 4: Depressurisation (decompression)
At the end of the session, the pressure is lowered slowly over 10 to 15 minutes. You may feel a slight popping sensation in your ears, similar to compression. The technician will guide you through this phase.
How Long Does a Typical HBOT Treatment Plan Last?
A single session lasts 60 to 120 minutes including compression and decompression time. Most treatment plans involve 20 to 40 sessions, scheduled once or twice daily, five days per week. The exact number depends on your condition and your physician’s treatment plan.
| Condition | Typical Sessions | Frequency |
|---|---|---|
| Non-healing wounds | 20–40 | 5 days/week |
| Radiation injury | 20–40 | 5 days/week |
| Carbon monoxide poisoning | 3–5 | Daily (urgent) |
| Decompression sickness | 1–5 | As needed (emergency) |
| Sudden hearing loss | 10–20 | 5 days/week |
What Are the Common Side Effects of Hyperbaric Oxygen Therapy?
HBOT is considered a safe, well-tolerated treatment when administered in an accredited facility by trained staff. Based on PubMed research, the most commonly reported side effects include:
| Side Effect | Frequency | Details |
|---|---|---|
| Middle-ear barotrauma | Most common | Ear pressure or mild discomfort during pressurisation. Usually prevented with proper equalisation techniques. |
| Temporary myopia | Occasional | Mild, reversible near-sightedness that typically resolves within weeks of completing treatment. |
| Sinus pressure | Occasional | Similar to ear pressure. Patients with sinus congestion should inform staff beforehand. |
| Fatigue | Common | Many patients feel tired after sessions. This is a normal response. |
| Oxygen toxicity seizure | Very rare | Occurs in fewer than 1.5% of patients according to meta-analysis data (Elfil et al., 2025). |
A Canadian feasibility study at Toronto General Hospital reported that mild middle-ear barotrauma occurred in 3 of 17 patients and new-onset myopia in 4 of 17, with all side effects resolving after treatment completion (Curtis et al., 2021).
What Should You Do After Each HBOT Session?
- Hydrate. Drink plenty of water after your session to support your body’s healing response.
- Rest if needed. Feeling tired after treatment is normal. Plan for a quiet afternoon if possible, especially during your first few sessions.
- Eat a balanced meal. If you fasted for blood sugar management, eat soon after your session.
- Report any concerns. If you experience persistent ear pain, vision changes, or any unusual symptoms, contact your hyperbaric clinic promptly.
- Attend all scheduled sessions. Consistency is important for treatment effectiveness. Missing sessions can reduce the benefits of your overall treatment plan.
Frequently Asked Questions About Hyperbaric Treatment
Is hyperbaric oxygen therapy painful?
No. HBOT is a painless treatment. The most common sensation is mild ear pressure during pressurisation, similar to what you experience on an aeroplane. Staff will teach you simple techniques to manage this discomfort.
Can I bring my phone or tablet into the chamber?
No. Electronic devices, including mobile phones and tablets, are not permitted inside hyperbaric chambers due to fire safety regulations in the oxygen-enriched environment. Many clinics provide entertainment options such as television screens.
Will I feel claustrophobic in the chamber?
Some patients feel anxious in a monoplace chamber. If you have concerns about enclosed spaces, speak with your clinic beforehand. Multiplace chambers offer a more open environment, and some clinics can provide mild sedation if necessary.
How much does hyperbaric oxygen therapy cost in Canada?
Costs vary by province and clinic. In provinces where HBOT is covered by the provincial health plan – such as OHIP in Ontario for approved indications – there is no out-of-pocket cost at eligible facilities. Private clinic sessions typically range from $150 to $400 per session. Some private insurance plans may cover HBOT. Check the Canada Hyperbarics coverage guide for province-specific details.
Can children receive hyperbaric oxygen therapy?
Yes. Children can receive HBOT for approved indications. Paediatric patients are supervised closely by trained staff, and a parent or guardian may be permitted to accompany the child depending on the chamber type and facility policy.
How soon will I notice results from HBOT?
Results vary by condition and individual response. Some patients notice improvement within the first few sessions, while others may not see noticeable changes until completing 15 to 20 sessions. Your treating physician will monitor your progress and adjust the treatment plan as needed.
Are there any conditions that prevent someone from receiving HBOT?
Certain conditions may be contraindications for HBOT, including untreated pneumothorax, certain chemotherapy medications, and some types of implanted medical devices. Your hyperbaric physician will conduct a thorough screening before treatment begins. Visit the Canada Hyperbarics research page for more information on indications and safety.
Take the Next Step
If your physician has recommended hyperbaric oxygen therapy, you are taking an important step toward your recovery. Use the Canada Hyperbarics clinic directory to find an accredited hyperbaric facility in your province, or explore our conditions page to learn more about how HBOT may help your specific situation.
This content is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before starting any new treatment. Hyperbaric oxygen therapy should only be administered by trained professionals in accredited facilities.