What Happens During a Mild Hyperbaric Oxygen Therapy Session

Preparing for Your Session

Arrive in comfortable, loose-fitting cotton clothing — synthetic fabrics can generate static electricity in the chamber. Remove all metal jewellery, watches, and electronics. Most clinics provide storage lockers for personal items.

Eat a light meal 1-2 hours beforehand rather than arriving hungry or overly full. Avoid alcohol and carbonated drinks for 4 hours prior, as these can increase the risk of decompression discomfort. If you're prone to claustrophobia, mention this during your consultation — many chambers have clear viewing panels that help.

Bring something to occupy your mind during the session: a book, tablet (if permitted), or simply plan to rest. Some facilities offer entertainment systems, but confirm availability when booking. If you wear contact lenses, consider switching to glasses for the day, as pressure changes can occasionally cause lens discomfort.

Inside the Chamber

The chamber resembles a large transparent tube or room, depending on the facility. You'll either lie on a padded surface or sit in a comfortable chair. Once sealed inside, the operator begins gradual pressurisation — a process that typically takes 10-15 minutes.

As pressure increases, you'll feel sensations similar to descending in an aircraft. Your ears may pop or feel full. Swallowing, yawning, or gently pinching your nose and blowing can help equalise ear pressure. The operator monitors your comfort throughout and can pause pressurisation if needed.

Once at treatment pressure (usually 1.3-1.5 atmospheres), you'll breathe pure oxygen through a mask or nasal cannula. This phase lasts 60-90 minutes. Many people find it surprisingly peaceful — the chamber is quiet except for the gentle hum of oxygen flow. Some drift off to sleep.

Depressurisation takes another 10-15 minutes. You'll feel your ears adjusting again as pressure gradually returns to normal. The entire session spans 90-120 minutes from entry to exit.

What You Might Feel

During treatment, most people report feeling relaxed or drowsy. The increased oxygen levels can create a mild sense of wellbeing, though dramatic euphoria is uncommon. Some experience slight tingling in fingers or toes as circulation adjusts to the higher oxygen concentration.

Ear pressure is the most noticeable sensation. A few people develop mild sinus pressure, particularly if they have congestion. These feelings typically resolve quickly after the session. Occasionally, vision may seem slightly sharper immediately after treatment due to increased oxygen to the optic nerves.

After your session, you might feel energised or conversely, quite tired. Both responses are normal. Some people notice clearer thinking or improved mood, whilst others feel no immediate change. First-time users sometimes experience mild headaches, which usually diminish with subsequent sessions.

Benefits accumulate gradually rather than appearing dramatically after single treatments. Most practitioners recommend completing at least 10 sessions before evaluating effectiveness.

Post-Session Care

Immediately after treatment, avoid sudden position changes — sit quietly for a few minutes before standing. Drink plenty of water over the following hours to support cellular processes and help eliminate metabolic byproducts.

Some practitioners suggest avoiding alcohol for 4-6 hours post-session, as your body's oxygen processing may be temporarily enhanced. If you're diabetic, monitor blood glucose levels more frequently for the remainder of the day, as oxygen therapy can occasionally affect blood sugar.

Light exercise like walking is fine, but avoid intense physical activity for 2-3 hours. Your body may be processing increased oxygen levels, and demanding activities could cause fatigue. Many people schedule sessions in late afternoon or early evening to allow for restful evenings.

Keep a simple diary noting energy levels, sleep quality, and any symptoms you're targeting. This helps track progress over multiple sessions and adjust treatment frequency if needed.

Treatment Schedules and Expectations

Most conditions require 20-40 sessions for optimal benefit, typically delivered 3-5 times weekly initially, then reducing to maintenance sessions. Acute injuries might respond to intensive daily treatments for 1-2 weeks, whilst chronic conditions often need longer protocols spread over several months.

Athletes sometimes use single sessions for recovery, though research suggests cumulative effects are more significant. Wellness-focused treatments commonly involve 10-20 sessions as an initial course, with periodic top-ups every few months.

Improvement timelines vary considerably. Some people notice enhanced energy or sleep quality within days, whilst tissue healing benefits may take weeks to become apparent. Brain injury recovery protocols can span months, with subtle cognitive improvements emerging gradually.

Costs typically range from £40-80 per session, with package deals reducing per-session rates. Treatment isn't available on the NHS for most conditions, though some private insurance policies may contribute towards medically prescribed protocols.