Hyperbaric oxygen, and not hyperbaric air, resulted in increased insulin sensitivity in diabetic volunteers

Clinical bottom line:

1. Exposure to hyperbaric oxygen resulted in an increased insulin sensitivity in diabetic patients compared to no change in sensitivty on exposure to hyperbaric air.
2. This study shows that it is oxygen breathing and not pressurization that drives this change.

Citation/s:1. Wilkinson DC, Chapman IM, Heilbronn LK. Hyperbaric oxygen but not hyperbaric air increases insulin sensitivity in men with type 2 diabetes mellitus. Diving Hyperb Med. 2020 Dec 20;50(4):386-390. doi: 10.28920/dhm50.4.386-390.

Lead author's name and fax: Dave Wilkinson Email: dwi75741@bigpond.net.au

Three-part Clinical Question:For patients with type-2 diabetes, does the administration of hyperbaric air compared to hyperbaric oxygen, result in increased sensitivity to insulin?
Search Terms: Diabetes, insulin sensitivity, hyperbaric air

The Study:Single-blinded concealed randomised controlled trial with intention-to-treat.
The Study Patients: Adult patients over 40 years with Type-2 diabetes mellitus.
Control group (N = 12 ; 11 analysed): Application of a hyperinsulinaemic euglycaemic glucose clamp technique designed to measure insulin sensitivity before, during and after a 2 ATA, 100% oxygen breathing period of 90 minutes.
Experimental group (N = 13 ; 13 analysed): As above but breathing air at the same pressure.

The Evidence:



HBOT Group

HBA Group


95% CI





Glucose infusion rate (mg/m-sq/min) at steady state 2






-6,725 to 6,707

1. Well-conducted but small experiment with good methodology, well-reported.
2. Baseline session conducted after a 10 hour fast and lasting for 3.5 hours at 1 ATA breathing air to establish insulin sensitivity at normal conditions.
3. Standard dose of insulin infused and glucose infusion rate varied to maintain euglycaemia.
4. Baselines were different between groups and the authors measured the steady state glucose infusion rate twice during the hyperbaric exposures. The figures here are for the second period and show no important difference in the raw numbers.
5. Glucose infusion rate increased by 26% in the HBO group compared to no change in the HBA group (P= 0.04).

Appraised by:Mike Bennett m.bennett@unsw.edu.au; Monday, 18 April 2022
Kill or Update By: April 2025