Gatorade is so 2014
                                
                                
                                    (Newser) -
                                    Want to exercise longer without feeling wiped out? A new study suggests adding beet juice to your diet. The research, published in the  American Journal of Physiology: Regulatory, Integrative and Comparative Physiology , zeros in on nitrate, which is found in beet juice and converted to nitric oxide in the body;...