Cardiorespiratory optimal point as a submaximal evaluation tool in endurance athletes: An exploratory study

Area of Science:

• Exercise Physiology
• Sports Science
• Cardiorespiratory Fitness

Background:

• The cardiorespiratory optimal point (COP), the point of lowest minute ventilation to oxygen consumption ratio (VE/VO2), is crucial for assessing cardiorespiratory efficiency.
• Determining COP at submaximal intensities is valuable when maximal exercise testing is not advisable, such as during competitive periods or off-season training.
• The physiological determinants of COP and its influence on maximal and submaximal exercise variables remain incompletely understood.

Purpose of the Study:

• To identify the physiological determinants of the cardiorespiratory optimal point (COP) in highly trained male and female athletes.
• To investigate the influence of COP on maximal and submaximal variables during cardiopulmonary exercise testing (CPET).
• To explore the utility of COP as a submaximal index for monitoring cardiorespiratory efficiency in athletes.

Main Methods:

• Cardiopulmonary exercise testing (CPET) was performed on 9 female and 24 male athletes to determine COP, ventilatory threshold 1 (VT1), ventilatory threshold 2 (VT2), and maximal oxygen uptake (VO2max).
• Principal component analysis (PCA) was employed to analyze the relationships between variables and identify the main factors explaining COP variance.
• Data analysis included comparisons of COP values between male and female athletes.

Main Results:

• Significant differences in COP were observed between sexes, with males exhibiting a lower COP (22.6 ± 2.9 VE/VO2) compared to females (27.2 ± 3.4 VE/VO2).
• In both male and female athletes, the COP was identified at an intensity preceding ventilatory threshold 1 (VT1).
• Principal component analysis indicated that 75.6% of the variance in COP was explained by principal component 1 (expired CO2 at VO2max) and principal component 2 (minute ventilation at VT2).

Conclusions:

• The cardiorespiratory optimal point (COP) is influenced by expired CO2 at VO2max and minute ventilation at VT2, suggesting these factors are key determinants of cardiorespiratory efficiency.
• COP serves as a valuable submaximal index for monitoring and assessing cardiorespiratory system efficiency in endurance athletes.
• The findings support the use of COP assessment during various training phases, including off-season, competitive periods, and athlete reconditioning.