If you are considering or currently undergoing hyperbaric oxygen therapy (HBOT), you might be wondering about its side effects. A common question patients ask is: Does Hyperbaric Oxygen Therapy Make You Tired? The science provides a nuanced answer that involves how your body metabolizes increased oxygen levels. While some people report fatigue after a session, it is often related to the body’s natural recovery process and the heightened energy expenditure required for cellular repair.

Understanding HBOT and Energy Expenditure

Hyperbaric oxygen therapy involves breathing pure oxygen in a pressurized chamber. This process significantly increases the oxygen concentration in your blood, which promotes healing, reduces inflammation, and stimulates the production of stem cells. However, these complex biological processes require energy. When your body shifts into high gear to repair damaged tissues, it can temporarily deplete your energy reserves. This biological demand is a primary reason why Does Hyperbaric Oxygen Therapy Make You Tired is a valid concern for many patients. The therapy essentially encourages your cells to work harder, which can lead to a feeling of mild, temporary fatigue.

The Role of Increased Oxygen Levels

One of the immediate effects of HBOT is a surge in tissue oxygenation. This sudden increase can cause a shift in your metabolic state. While oxygen is essential for energy production (ATP), the body sometimes undergoes a mild adjustment period. Some individuals experience a feeling of relaxation or drowsiness during the session itself, which can be mistaken for post-treatment fatigue. However, persistent tiredness is often linked to the anti-inflammatory response triggered by the therapy, as the body uses energy to clear out waste products from damaged cells.

Comparing Immediate vs. Cumulative Fatigue

It is important to distinguish between feeling tired immediately after a single session and experiencing cumulative fatigue over a series of treatments. Most patients report feeling energetic or relaxed right after a session, not drowsy. The exhaustion that does occur is often a delayed response. Clinical observations suggest that cumulative fatigue can appear after several weeks of daily sessions. This is more common in protocols treating chronic conditions like wound healing or Lyme disease. In these cases, the fatigue is a sign that the regenerative processes are actively resolving inflammation.

Common Factors Influencing Post-HBOT Fatigue

Length and Pressure of the Session

The duration and atmospheric pressure of your HBOT session directly impact your body’s energy demands. Longer sessions (over 90 minutes) at higher pressures (above 2.0 ATA) require more physiological effort. Patients undergoing aggressive protocols for acute injuries may feel more tired than those receiving mild, lower-pressure therapy for general wellness. The body’s oxygen detoxification and cellular repair systems are taxed proportionally to the “dose” of oxygen.

Underlying Health Conditions

The reason you are seeking HBOT often dictates how you will feel afterward. For instance, patients with chronic fatigue syndrome, fibromyalgia, or long COVID might find that HBOT initially exacerbates feelings of tiredness before improvement occurs. This phenomenon, sometimes called a “healing crisis” or “herxheimer reaction,” occurs when the body rapidly removes toxins and pathogens. Conversely, healthy individuals using HBOT for athletic recovery often report increased alertness and reduced muscle soreness.

Hydration and Nutrition Status

Your cellular hydration and energy stores before a session play a crucial role. Hyperbaric chambers are often dry