Nutritional Strategies and Hydration before, during and after a hockey match FIH Medical Seminar, The Hague, June 4 2014 Dr Marco Mensink, Wageningen University, Division of Human Nutrition
training Field Hockey skills speed tactics Endurance capacity Power talent anthropometrics psychological
Sports Nutrition Pyramid
Energy Metabolism
ATP resynthesis RATE DELAY CAPACITY Phosphocreatine very high instantaneous very small (anaerobic) Glycolysis high seconds small Oxidative metabolism Glycogen moderate minutes large Blood-borne glucose low ~ 90 min small Lipids low > 2 hour unlimited
Game player Football, Soccer, Hockey, Tennis, Intermittent exercise Soccer: 1000 bouts of action 8-13 km covered Jogging (37%), walking, cruising, sprinting (11%) ~75% V02 max Blood lactate ~4-6; peak 8-12 mmol/l
Intermittent high intensity exercise With repeated sprints power output supported by PhosphoCreatine and aerobic metabolism
Nutritional Strategies
(Phospho)Creatine High-energy Phosphate Contributes to high-intensity exercise for initial seconds, up to 20 sec Restoration aerobic (O 2 availability), within 4-5 minutes Muscle (95% of body store) Sources Diet (meat; supplements!) Endogenous production liver
Carbohydrates The Main Energy Food
Glycogen Skeletal Muscle and Liver Limited amount Exercise intensity Anaerobic glycolysis Oxidative breakdown
Carbohydrates: Diet Light Moderate exercise Moderate to heavy exercise Extreme exercise 3-5 g/kg/day 5-7 g/kg/day 7-12 g/kg/day 10-12+ g/kg/day
Carbohydrates: (before) Exercise Pre-event meal Pre-event snack GI complaints rebound hypoglycaemia 30-75 min Single/multiple CHO -> mouth rinse 1-2 hour Single/multiple CHO -> 30 g/h 2-3 hour Single/multiple CHO -> 60 g/h > 2.5 hours Glucose:fructose (2:1) -> 90 g/h Nutritional training essential
Carbohydrates: Recovery Immediate (0-4h): Thereafter: 1.0-1.2 g/kg/h daily scheme
Practical recommendations
Protein The Tissue Builder
Protein: optimizing training adaptation
Protein recommendations.. individuals engaged in regular exercise training require more dietary protein than sedentary individuals... intakes of 1.4 2.0 g/kg/day.. is not only safe, but may improve the training adaptations to exercise training... possible.. to obtain.. protein requirements through a varied, regular diet, supplemental protein is a practical way of ensuring adequate intake...superiority of one protein type over another.. remains to be convincingly demonstrated... appropriately timed protein intake is an important component of an overall exercise training program.
Protein balance
Optimizing training adaptation
Optimizing training adaptation Provide sufficient protein with each main meal (20-25 g) Ingest 20-25 g dietary protein during/immediately after exercise Whey (dairy) is an excellent source Consider protein prior to sleep Co-ingest carbohydrates to replete glycogen
Practical recommendations
Hydration
Hydration status
Fluid balance during exercise Fluid balance/sweat rate: prebw-postbw+fluid-urine
Practical recommendations Before Exercise Start well-hydrated Pay attention to thirst Drink last 2 hours 5-10 ml per kg -> pale yellow urine Hyperhydrate During Exercise Short-term: drink to sweat loss Long-term: drink to thirst or prevent > 2-3% BW loss Cold drinks (thermoregultaion) overdrinking (hyponatremia)
Beverage composition Sodium Decreases diuresis (urine output) Stimulates thirst Carbohydrates Sodium-glucose co-transport Gastric emptying Glycogen restoration Palatability
Issues in post-exercise rehydration Practical issues: opportunities, conscious decisions Voluntary intake: 30-70% of sweat losses People fail to rehydrate Difficult after high levels of hypohydration (2-5% BM) or interval between exercises short (6-8h) Solid foods
Practical recommendations After Exercise 150% of sweat loss add to your liquid: Sodium and Glucose Slower drinking (GI complaints) Palatable is key Limit alcohol intake Solid foods / sodium replacement
Summary Carbohydrates: the Energy Food Daily diet Pre/during/post exercise Protein: The Muscle Builder 20-25 gram per meal and post exercise Rehydration: 150% sweat loss Sodium content
Recovery meal/drink Repletion: Carbohydrates -> 1-1.5 g/kg Rehydration: Fluid Reparation: Protein -> 10-20 gram
Nutritional Strategies and Hydration before, during and after a hockey match marco.mensink@wur.nl