Food as Fuel for Fitness

CNS) fatigue is associated with reduced neural drive – either an inability to maintain it or unwilling too – protective mechanism?

• is more closely associated with physiological changes at the local level e.g., unable to match energy demand in the muscles

If glycogen stores are depleted, free fatty acids increase in the blood, to be used as fuel Tryptophan is a precursor for serotonin, and therefore more serotonin goes to the brain • Serotonin promotes lethargy and fatigue; thus, could reduce exercise performance

If exercise is very high intensity (≥100% VO2max and short duration (5-10 min) there does not seem to be an additional benefit to maximising glycogen stores (Hawley et al., 1997).

Consuming 7 – 10 g/kg/ BM 24 – 36 hours prior to competition should be adequate to optimise glycogen stores - as long as there are no CHO restrictions in the days preceding this - 770 grams for a 77kg person

Important to be mindful of those who might restrict intake for weight management reasons (Burke, 2017) Also important to avoid muscledamaging exercise in the days leading up to exercise Zone 1 or zone 2 relatively for heart rate

• Events are highly reliant on glycogen as a fuel source, so CHO loading encouraged Several different protocols have been suggested and modified over-time • 60s • 3 days of depletion followed by 3 days of loading • 80s • 3 days of loading – no depletion phase • 20s

• 36 – 48 h prior should be sufficient to optimise stores (10-12 g/BM/day) • CHO loading improved performance in these events

• CNS fatigue • GI discomfort • Gastro-intestinal • Stiches • Stomach Pain • Carbohydrate availability/depletion of glycogen • Hypoglycemia • Low blood sugar • Poor recovery • Lack of sleep • Lack of Carbohydrates • Dehydryation • when 2% of our body mass has been lost through sweating

The aim of pre-exercise specific fuelling is to implement nutritional strategies that will optimise performance; specifically, delay the onset of factors that cause fatigue/negatively affect performance

1 hour pre exercise - Carbohydrate-rich snacks that are low in fibre, fat, and protein - Bannana - Jam Sandwich - Haribos - Yoghurts - Cornflakes - Granola - No wholemeal pasta or meals - Remember – some athletes experience hypoglycaemia - Some may get low blood sugar due to hyper consumption - Avoid by providing low GI CHO, consuming CHO in event and importantly, experiment in training!

• Should be consumed 1 – 4 h before competition • Should be just to restore/top up glycogen stores – the heavy lifting should have been done in the previous few days! • Prevent hunger and GI distress • Low in Fibre or Fats due to the time that it takes for the body to digest it • Carbohydrate-rich (1-4 g/kg/BM) • Restore liver glycogen content after sleeping

• 10 g per kg/BM/day = 10 x 56 = 560 grams of carbohydrate • Only for the Elite Elite level

Muscle glycogen and plasma glucose are the most important for exercise Exercise is associated with different training adaptations - Endurance training - Strength Training - Sprint training - Capilarry density - Glycogen density - Muscle size - Plasma Volume

The principal role of carbohydrates is to provide energy for muscular contraction (Gleeson & Jeukendrup, 2011) - We consume carbohydrates in the diet and store them in muscle and liver in the form of glycogen

• Liver stores aropund 320-440 calories of glycogen - All of this gets broken down into glucose and enters your muscles - It is well established that there is a heavy reliance of muscle glycogen during high intensity exercise - If insufficient carbohydrates consumed, then suboptimal muscle glycogen for competition is possible - Stomach can break it down as well • 12 – 16 g/kg W.W. in muscles (300 – 400 g of CHO or 1200 – 1600 Kcal