The maximum ability to utilize oxygen (VO2max) was observed in active duty marine reserves before and after the implementation of a high intensity interval training program (HIIT). Eleven males volunteered for this study of 32± 6 years of age and heights of 1.77 ± 0.08.With the implementation of HIIT in marine training protocol there was a significant difference seen in VO2max pre and post HIIT training p =.00. Paired t-tests were used to find differences between pre and post HIIT protocol on VO2MAX (alpha = 0.05). This is suggestive that HIIT is effective in improving VO2MAX. Further research should be done on HIIT and its effectiveness on VO2MAX. This should include but not be limited to larger sample sizes, control groups, and high volume training groups.