Black Tea Extract Reduces DOMS, Oxidative Stress, and Cortisol Responses to High-Intensity Interval Training

Abstract

Muscle soreness and decreased performance often follow a bout of high-intensity exercise. By reducing these effects, an athlete can train more frequently and increase performance. PURPOSE: To examine whether a high-potency, black tea extract (BTE) alters delayed onset muscle soreness (DOMS), oxidative stress, and cortisol (CORT) responses to high-intensity anaerobic exercise. METHODS: College-age males (N=18) with 1+yrs of weight training experience completed a double-blind, placebo-controlled, crossover study. Each subject completed two testing sessions (T1 and T2), which consisted of a 30s Wingate Test plus eight 10s intervals. Blood samples were obtained before, and 0, 30 and 60 min following the sessions for analysis of CK, GSH:GSSG, and CORT. Muscle soreness was recorded at 24 and 48 h post-test using a visual analog scale. Subjects consumed the BTE or placebo (PLA) for 9 d. T1 occurred on day 7 and administration continued for 2 more days during the assessment of DOMS. Each subject underwent a 5 d washout before administering the product they did not receive in the initial supplementation phase. BTE supplementation consisted of 1,760mg BTE·d-1. Significance was set at p<.10 to protect against type II error. RESULTS: Across the 48 h post-exercise period, BTE produced significantly lower DOMS (24 h=1.1+0.3 cm; 48 h=0.9+0.3 cm) compared to PLA (24 h=2.1+0.4 cm; 48 h=1.9+0.5 cm), P<.001. A Time × Condition interaction (P=.044) emerged for the GSH:GSSG ratio, with BTE having less oxidative stress at 30 and 60 min post compared to PLA (P<.02). An interaction also emerged for CK (P=.005), with BTE having significantly lower CK by 30 min post (228+33 U·L−1 vs 333+41 U·L−1, P=.005) despite similar values immediately post-exercise (316+55 U·L−1 vs 334+49 U·L−1, P=.69). CORT secretion was altered both by Time (P<.001) and Condition (P=.09). Though both BTE and PLA had elevated CORT values post-exercise, the BTE condition had lower overall CORT, which was confirmed by AUC analysis (P=.098). CONCLUSIONS: BTE appears to enhance recovery or blunt some of the physiological responses to acute anaerobic intervals and is associated with a reduction in DOMS. This may help optimize performance during an acute bout of exercise while also speeding the recovery process in order to facilitate engaging in future training. Supported by WellGen, Inc.