Hyperbaric oxygen breathing improved exercise performance and oxygen consumption in normobaric conditions for 3 hours following exposure.

Clinical Bottom Line:
1. Hyperbaric oxygen exposure improved performance capacity and oxygen consumption for at least 3 hours post-exposure.
Appraised by: Mike Bennett, Dept of Diving and Hyperbaric Medicine, Prince of Wales Hospital
Sydney; Monday, 18 January, 1999

Clinical Scenario: An athlete presents suggesting that aerobic performance will be enhanced by exposure to hyperbaric oxygen.
Three-part Question: In athletes, does exposure to hyperbaric oxygen compared to normal air breathing, result in enhanced aerobic performance and for how long?
Search Terms: Hyperbaric oxygenation, exercise.

The Study:
Non-blinded randomised controlled trial with intention-to-treat.
Fit female physical education students with no specific contra-indications to hyperbaric oxygen.
Control group (N = 18 ;18 analysed): All participants had a standard treadmill test with increasing exertion required in a discontinuous manner, three days before hyperbaric exposure.
Experimental group (N = 18 ;18 analysed): All participants were randomised into three arms and then had hyperbaric oxygen at 2.8 ATA for 60 minutes. Each group was tested at a different time post-HBO: 30 mins, 3 hours and 6 hours after completion of HBO protocol.

The Evidence:
Non-event outcomes
Before
After
P-value
Maximum performance (30 mins group)
10.1
11.4
<0.05
Maximum performance (3 hour group)
10.5
12.4
<0.05
Maximum performance (6 hour group)
11.6
12.7
>0.05

Comments:
1. Placebo effect of hyperbaric oxygen not tested - no blinding of subjects.
2. The ventilation dependent oxygen uptake ratio, respiratory exchange ratio and lactate concentrations before and after HBO exposure did not change significantly in any group.
3. No a priori justification is made for the choice of times to test performance.

Expiry date:March 2013
References:
1. Cabric M, Medved R, Denoble P, Zivkovic M, Kovacevic H. Effect of hyperbaric oxygenation on maximal aerobic performance in a normobaric environment. Journal of Sports Medicine and Physical Fitness 1991; 31:362-366.


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