Here are four reasons why you should start drinking tart cherry juice. 1. Great Source Of Vitamins. Tart cherry juice is a great source of vitamins and minerals, including manganese, potassium and vitamins A and C. 2. Improve Sleep. Tart cherries are high in melatonin, a hormone that helps regulate our internal circadian clocks. 3. Enhance Exercise Performance. Studies have shown that tart cherry concentrate can enhance endurance exercise performance. 4. Reduce Muscle Soreness. Drinking tart cherry juice in the days before and after intense exercise may reduce muscle soreness