2013 ASHS Annual Conference

Strenuous exercise, such as marathons, induces inflammation and oxidative stress in humans.  Addition of a carbohydrate (CHO) source to liquid intake during exercise helps prevent inflammation.  Watermelon contains large amounts of free water as well as sugars, some electrolytes and vitamins, lycopene, and amino acids. Watermelon juice, consisting of the puree from the flesh, was tested against a popular carbohydrate beverage to determine ability to alleviate oxidative stress, inflammation, and arterial stiffness in older male athletes (48 ± 2 years).   Subjects consumed watermelon or no watermelon for 2 weeks prior to a 75 km bicycling trial.  During exercise, subjects consumed either watermelon (0.2 g CHO/kg weight) or 6% CHO drink ever 15 minutes.  The study was designed as a crossover, so drink intake was switched following the first exercise trial.  Indirect effects on arterial stiffness were determined using augmentation index (radial artery waveforms) and brachial blood pressure.  Both watermelon and CHO drink fully supported energy demands of exercise.  Intake of watermelon increased total nitrate and antioxidant capacity but not other biomarkers. Post-exercise augmentation index was reduced in both groups, but less so in subjects receiving watermelon.  Our results indicate that watermelon juice can be used as a carbohydrate source to offset exercise inflammation.