Validity of 3 protocols for verifying VO2 max

Area of Science:

• Exercise Physiology
• Cardiorespiratory Fitness Assessment

Background:

• Maximal oxygen uptake (VO2 max) is a key indicator of cardiorespiratory fitness.
• Verification bouts are used to confirm 'true' VO2 max, but their validity within a single testing session is not well established.

Purpose of the Study:

• To evaluate the validity of VO2 max measurements using verification bouts following graded exercise tests (GXTs) of different durations within a single visit.
• To determine the optimal GXT duration for reliable VO2 max assessment.

Main Methods:

• Twelve recreationally trained men completed three GXT protocols (short, middle, long duration) followed by exhaustive verification bouts on separate days.
• Verification bout intensity was set at speeds equivalent to two stages minus the end-GXT speed.
• VO2 max, heart rate (HR), and respiratory exchange ratio (RER) were measured.

Main Results:

• No significant differences in VO2 max were found between the different GXT durations.
• The middle duration GXT protocol demonstrated the strongest validity for VO2 max (ICC α=0.97).
• The long GXT protocol showed a slightly higher maximal heart rate, and RER measurements were inconsistent across protocols.

Conclusions:

• Graded exercise testing with verification bouts during a single visit is a valid method for measuring 'true' VO2 max.
• A GXT duration of approximately 10 minutes is optimal for achieving reliable VO2 max measurements.
• The findings support the use of single-visit GXT with verification for accurate cardiorespiratory fitness assessment.