CARBOHYDRATE AND SODIUM INTAKE DURING ULTRATRIATHLON DEPENDS ON THE ORGANIZER'S FOOD SUPPLY

Abstract

243 Food intake and fluid balance were recorded and analysed in 25 athletes during two ultratriathlons (A, n=13 and B, n=12). In B, CHO rich beverages and solid food were available throughout the race, whereas in A, beverages contained almost no CHO. Thus CHO intake of the athletes in A was exclusively dependent on solid food. The consequence was a significantly lower mean CHO intake in A than in B (34±19 g/h vs. 62±21 g/h, p<0.05). 7 athletes experienced an unexpected but definite impairment of performance capacity during A or B. Five of them participated in A and had the lowest CHO intake of all subjects (<20-30 g CHO). The mean fluid intake (A: 825±179 ml/h, B: 875±253 ml/h, n.s.) was below the calculated fluid loss (1.2±0.2 l/h) leading to a total fluid deficit of 2,3±1,0 l. In B, sodium balance was calculated from changes in sodium plasma levels, urinary excretion and bioelectrical multifrequence body water analysis before and after the race. Sodium deficit was −5.4±1.5 g (total loss: 7.1±1.7 g; uptake: 1.8±0.4 g). This deficit was mainly caused by the insufficient sodium intake during the race (181±43 mg/h) which was far from compensating the average loss of 722±146 mg/h! As a consequence, the extracellular fluid volume decreased by 1.5±0.3 l and sodium plasma levels decreased from 136.0±1.9 mmol/l to 134.4±2.1 mmol/l (p<0.05). A beverage with a sodium content of 300-700 mg/l might have easily compensated this deficit. But none of the beverages in A or B had a sodium content above 48 mg/l! The organizer's responsibility for an adequate food supply (at least one hypo- or isotonic beverage with a sodium content of 300-700 mg/l and a CHO content of 40-80 g/l throughout the race) has to be emphasized in ultraendurance events to prevent athletes from developing CHO- and sodium deficiencies.