FIH Medical Seminar, The Hague, June 4 2014 Dr …...Nutritional Strategies and Hydration before,...

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

Field Hockey

skills

tale

nt

Endurance capacity tactics

Power

train

ing

speed 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

Blood-borne glucose

Lipids

moderate

low

low

minutes

~ 90 min

> 2 hour

large

small

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 (O2 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 3-5 g/kg/day

Moderate exercise 5-7 g/kg/day

Moderate to heavy exercise 7-12 g/kg/day

Extreme exercise 10-12+ g/kg/day

Carbohydrates: (before) Exercise

Pre-event meal GI complaints

Pre-event snack 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): 1.0-1.2 g/kg/h

Thereafter: ‘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