RPE Association with Lactate and Heart Rate during High-Intensity Interval Cycling
Purpose: Physiological and perceptual measures during interval exercise are not well understood. The current study therefore examined the correspondence between RPE, HR, and blood lactate concentration ([La]) during interval cycling.
Methods: V̇O2peak and the 4.0 mmol·L-1 lactate threshold were determined. In session 2, subjects (N = 12) warmed up (10 min, 0 W) and completed five 2-min intervals (INT) at >4 mmol·L-1 workload, each separated by 3 min of recovery (REC) (60 rpm, 0 W). HR, RPE, and [La] were recorded at 10 min, at the conclusion of each INT, and each REC and 5- and 10-min recovery.
Results: Repeated-measures ANOVA showed [La], HR, and RPE increased significantly across time (INT and REC). At each time point, repeated-measures ANOVA was used to compare standardized data (α = 0.05). RPE (at INT) intensified concurrently with HR and [La] at INT. Correlations were significant for INT (P ≤ 0.05) (HR-RPE: r = 0.63, [La]-RPE: r = 0.43). Similarly, RPE and HR for REC systematically increased with [La]. Correlations for REC were also significant (HR-RPE: r = 0.44, [La]-RPE: r = 0.34). Correlations were also significant for INT and REC combined (HR-RPE: r = 0.70, [La]-RPE: r = 0.22).
Conclusions: INT and REC independently showed moderate correspondence for RPE-[La] and RPE-HR. However, tighter overall coupling of HR with RPE (vs [La] with RPE) and a dissociation between RPE-[La] suggest RPE during intervals of intense cycling were more sensitive to acute metabolic demand (evidenced by HR) versus [La].