RPE-lactate dissociation during extended cycling

Area of Science:

• Exercise Physiology
• Sports Science
• Human Performance

Background:

• Understanding the relationship between physiological markers and perceived exertion is crucial for optimizing training.
• Blood lactate concentration ([LA]) and heart rate (HR) are commonly used indicators during exercise.
• Ratings of perceived exertion (RPE) provide a subjective measure of exercise intensity.

Purpose of the Study:

• To investigate the association between blood lactate concentration ([LA]), heart rate (HR), and ratings of perceived exertion (RPE) during 60 minutes of steady-state cycling.
• To determine if [LA] is a significant mediator of RPE during prolonged submaximal exercise.

Main Methods:

• 14 physically active college-aged subjects completed a 60-minute cycling test at a power output corresponding to a lactate threshold of 2.5 mmol/L.
• Measurements of HR, [LA], RPE-overall, RPE-legs, and RPE-chest were taken at regular intervals (5-60 minutes).
• Repeated measures ANOVA and correlation analyses were used to compare data points and assess relationships.

Main Results:

• Blood lactate concentration ([LA]) significantly decreased after 20 minutes, while RPE (overall, legs, chest) and HR significantly increased throughout the 60-minute trial.
• Significant positive correlations were found between HR and all RPE measures (RPE-O, RPE-L, RPE-C).
• Correlations between [LA] and HR, as well as [LA] and RPE, were weak and non-significant, indicating a dissociation.

Conclusions:

• A dissociation exists between blood lactate concentration and perceived exertion during extended submaximal cycling exercise.
• RPE demonstrates a "drift" upwards over time, independent of declining lactate levels.
• Blood lactate concentration is not a strong mediator of perceived exertion in prolonged steady-state cycling.