The Effect of Different Beverages on Acute Regeneration and Performance during Interval Running

Abstract

Purpose: Field studies show, that in several sports a major part of athletes are seriously dehydrated and carbohydrate depleted after a match. Therefore, during sports-game competitions, it is of great importance to optimize short-term regeneration such as fluid and carbohydrate replacement within breaks. In the present study, the influence of taste and composition of beverages on self-selected drink volumes and the resulting performance capacity was investigated during a simulated game. Methods: 11 athletes (3 female, 8 male) performed 5 treadmill-spiroergometries with a break of at least one week between tests. Test 1 consisted of a stepwise increase in speed (1,5 km x h-1 every 4 minutes, starting from 8-5 km x h-1) in order to determine maximal speed (vmax) and maximal physiologic data. The subsequent tests were applied in random order and consisted of two 30 min. interval runs with speeds depending on individual vmax of test 1. In the 15 min. break between the halves, subjects were offered one of four different beverages to drink ad libitum (Mineral water = MWT, a zero-alcohol beer with 6,4 % carbohydrate content (CHO) = PIT, a zero-alcohol beer with 7,5 % CHO = WET, a 10 % CHO caffeinated beverage = CCT). After the second half, subjects run at 90 % of vmax until exhaustion. Main Results: About one third of the sweat loss was compensated by the halftime drink. The volume of the ingested fluid ranged between 0,43 + 0,19 L and 0,51 + 0,24 L (mean + SD) with no significant differences between beverages. Spiroergometric parameters, as well as lactic acid concentrations, showed no obvious differences between tests 2 to 5. By contrast, running time to exhaustion was significantly longer in WET as compared to MWT and CCT (P=0,05).  Discussion: Taste and composition of a beverage appear to be no important influences on drink volume during competition. It is speculated that the differences in running time originate from different sources, a glycogen depletion in MWT and a decreased gastric emptying rate in CCT. Conclusions: In sports-game competitions, besides predetermined breaks also impromtu breaks have to be used in order to counteract dehydration. In order to substitute sweat and carbohydrates during and after exercise in a balanced way, zero-alcohol beer is a promising candidate.