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
10.1
11.4
<0.05
(30
minute group)
Maximum
performance
10.5
12.4
<0.05
(3
hour group)
Maximum
performance
11.6
12.7
>0.05
(6
hour group)
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: February 2005
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.
