Carbohydrate Ingestion Before and During Soccer Match Play and Blood Glucose and Lactate Concentrations

Abstract

Context: The ingestion of carbohydrate (CHO) before and during exercise and at halftime is commonly recommended to soccer players for maintaining blood glucose concentrations throughout match play. However, an exercise-induced rebound glycemic response has been observed in the early stages of the second half of simulated soccer-specific exercise when CHOelectrolyte beverages were consumed regularly. Therefore, the metabolic effects of CHO beverage consumption throughout soccer match play remain unclear.Objective: To investigate the blood glucose and blood lactate responses to CHOs ingested before and during soccer match play.Design: Crossover study. Setting: Applied research study.Patients or Other Participants: Ten male outfield academy soccer players (age ¼ 15.6 6 0.2 years, height ¼ 1.74 6 0.02 m, mass ¼ 65.3 6 1.9 kg, estimated maximal oxygen consumption ¼ 58.4 6 0.8 mLÁkg À1 Ámin À1). Intervention(s): Players received a 6% CHO-electrolyte solution or an electrolyte (placebo) solution 2 hours before kickoff, before each half (within 10 minutes), and every 15 minutes throughout exercise. Blood samples were obtained at rest, every 15 minutes during the match (first half: 0-15, 15-30, and 30-45 minutes; second half: 45-60, 60-75, and 75-90 minutes) and 10 minutes into the halftime break.Main Outcome Measure(s): Metabolic responses (blood glucose and blood lactate concentrations) and markers of exercise intensity (heart rate) were recorded.Results: Supplementation influenced the blood glucose response to exercise (time 3 treatment interaction effect: P .05), such that glucose concentrations were higher at 30 to 45 minutes in the CHO than in the placebo condition. However, in the second half, blood glucose concentrations were similar between conditions because of transient reductions from peak values occurring in both trials at halftime. Blood lactate concentrations were elevated above those at rest in the first 15 minutes of exercise (time-of-sample effect: P , .001) and remained elevated throughout exercise. Supplementation did not influence the pattern of response (time 3 treatment interaction effect: P ¼ .49).Conclusions: Ingestion of a 6% CHO-electrolyte beverage before and during soccer match play did not benefit blood glucose concentrations throughout the second half of exercise.Key Words: supplementation, sports drinks, football, intermittent exercise, rebound hypoglycemia Key PointsA 6% carbohydrate-electrolyte beverage ingested before and during soccer match play did not maintain blood glucose concentrations in the second half of match play. The efficacy of carbohydrate-fluid supplementation regimes that are recommended for high-intensity intermittent team sports players can be improved, and more effective carbohydrate-supplementation strategies can be developed to maintain blood glucose concentrations throughout soccer match play.

Half-Time Strategies to Enhance Second-Half Performance in Team-Sports Players: A Review and Recommendations

“…Notably, ingesting sucrose in the form of a 6% carbohydrate-electrolyte beverage before (i.e., within two hours of commencing exercise and within five minutes of starting each half) and during (i.e., every 15 minutes of exercise) simulated soccer-specific exercise attenuated a decline in soccer shooting performance; specifically relating to the speed of the shots taken post-exercise 5 . However, in agreement with pilot data reported by Bangsbo et al 44 , the provision of exogenous carbohydrates prior to and during soccer-specific caused ~30% reductions in blood glucose concentrations during the initial stages of the second half; a finding which has since been confirmed in both simulated and actual soccer match-play 4,6 . This exercise-induced rebound glycaemic response is most likely explained by an increased glucose uptake by the previously active muscles, lowered catecholamine concentrations, and reduced stimulation of liver glycogenolysis can cause transient reductions in blood glucose concentrations at the onset of the second half 44 .…”

“…Although often considered crucial for primarily tactical reasons, physiologically, half-time can be viewed as a recovery period following the previous bout of match-play, a preparatory period preceding subsequent competition, or a period of transition between the two halves 2 . Irrespective of the perceived function of this period, substantial physiological changes relating to acid-base balance 3 , the glycaemic response [4][5][6] and muscle (Tm) and core temperature (Tcore) changes [7][8][9][10][11] result from typically passive periods comparable in length to those observed during half-time (i.e., ~15 min).…”

The effects of match congestion on gait complexity in female collegiate soccer players

“…First, prolonged exercise is often associated with a loss of muscle glycogen and potential development of hypoglycemia . This can occur during a 90‐minute soccer match, and it may require more than 24 hours to fully restore depleted glycogen stores . Reduced muscle glycogen and subsequent hypoglycemia can reduce exercise performance as well as disrupt motor control during voluntary activity .…”

“…This can occur during a 90‐minute soccer match, and it may require more than 24 hours to fully restore depleted glycogen stores . Reduced muscle glycogen and subsequent hypoglycemia can reduce exercise performance as well as disrupt motor control during voluntary activity . Second, players participating in a soccer match typically experience muscle soreness and muscle damage for several days post‐match .…”

“…27 Reduced muscle glycogen and subsequent hypoglycemia can reduce exercise performance as well as disrupt motor control during voluntary activity. 26,28 Second, players participating in a soccer match typically experience muscle soreness and muscle damage for several days post-match. 3,29 The perception of muscle pain or discomfort resulting from prior exercise can alter motor control strategies 30 such that players may select a gait that is "least painful."…”