The research was aimed to study the effects of a 30 minute exposure to 2.5 ATA with 100% O2-inhalation on lactate concentration after muscular fatigue from incremental exercise on a cycle ergometer The subjects were 60 male naval cadets aged 20-23 years whose physical fitness was equivalent to the average athletes. All volunteers participated in the first VO2 max exercise test to obtain their baseline data and randomly assigned into 3 groups of 20. The 3 groups were: Rest recovery group (RR), Oxygen recovery group (OR), and the Hyperbaric oxygenation (HBO2) recovery group (HR). The volunteers took the incremental exercise test (Ordinary Lamp Protocol) on a cycle ergometer to exhaustion, then rested according to the above assigned groups. Blood samples were taken from each volunteer before the experiment, at exhaustion and every 5-minute intervals after the exhaustion for 30 minutes and immediately assayed for lactate concentration. The results showed significant decrease of blood lactate concentration at 15, 20 and 25 minutes intervals after the exhaustion in the HR group compared to the others. It might be initially concluded that HBO2 enhanced the rate of lactate removal from peripheral blood vessels, therefore it shortened the recovery time.