Acute Effects Of Different Cacao Polyphenol Intake On Post-resistance Exercise Arterial Stiffness In Young Men

Resistance exercise (RE) increases arterial stiffness. Polyphenol-rich dark chocolate (DC) intake has been reported to improve arterial function, although it has been suggested that the effects may differ with variations in polyphenol content. PURPOSE: This study investigated the acute effects of DC intake with different cocoa polyphenol content on arterial stiffness after RE. METHODS: Ten healthy adult males (mean age ± standard deviation: 23.1 ± 1.2 years) participated in this study. Participants completed a high-cocoa polyphenol (HCP) trial in which they consumed 1270 mg of cacao polyphenol per 50 g of DC, a medium cacao polyphenol (MCP) trial in which they consumed 635 mg, and a non-cacao polyphenol (NCP) trial with a double-blind randomized crossover design. The RE protocol consisted of 5 sets of 5 repetitions at 80% of one repetition maximum (1RM) bench press, and 5 sets of 10 repetitions at 70% of 1RM biceps curl. Brachial-ankle pulse wave velocity (baPWV) was recorded to measure systemic arterial stiffness, and carotid compliance and β-stiffness index were taken as measures of central arterial stiffness before DC intake (baseline), before RE, immediately after RE, and 30 and 60 min after RE. RESULTS: Baseline baPWV showed no significant differences between trials. Compared with baseline, baPWV significantly increased immediately after RE in all trials (NCP: 1108 ± 89 to 1281 ± 132 cm/sec, P = 0.001; MCP: 1086 ± 94 to 1242 ± 125 cm/sec, P = 0.001; HCP: 1100 ± 95 to 1218 ± 119 cm/ sec, P = 0.001). baPWV at 30 min(NCP: 1194 ± 124 cm/sec, P = 0.05; MCP: 1192 ± 107 cm/sec P = 0.001) and 60 min (NCP: 1210 ± 111 cm/sec, P = 0.001; MCP: 1177 ± 134 cm/sec P = 0.05) showed significant increase in NCP and MCP, but no significant difference was recorded in HCP (30 min: 1167 ± 127 cm/sec, P = 0.375; 60 min: 1176 ± 139 cm/sec, P = 0.079). Baseline carotid compliance showed no significant differences between trials, whereas carotid compliance significantly decreased immediately after RE and at 30 and 60 min after RE in all trials. Baseline β-stiffness index showed no significant differences between trials. Compared with baseline, β-stiffness index significantly increased immediately after RE, and 30 and 60 min after RE in all trials. CONCLUSIONS: These results suggest that the intake of polyphenol-rich DC may rapidly reduce the RE-induced increase in baPWV.