Effects of Dark Chocolate on Exercise Capacity in Sedentary Older Subjects: Underlying Mechanisms

We previously shown in patients with heart failure and type II diabetes that treatment with dark chocolate (DC) improves mitochondrial structure, indicators of mitochondrial biogenesis and oxidative stress in skeletal muscle (SkM). For this study, 17 sedentary subjects (mean age 50 years old) were randomized to placebo (n=8) or DC groups (n=9). In a double blind manner, subjects consumed either 2 squares of Hersheys' Extra Dark chocolate or placebo (20 g) for 3 months. Subjects underwent bicycle ergometry to assess VO2 max and power, lipid profile and SkM biopsy to investigate underlying mechanisms. In the DC group, there was a trend for an increase in V02 max (p=0.056 before vs. after) with no changes with placebo. In the DC group post-treatment there was an increase in maximum exercise related work (watts) achieved (p=0.03). The DC group showed significant increases in HDL levels (p=0.005) and a trend for decreases in triglycerides (p=0.07). SkM biochemistry showed significant increases in protein for m...