320 likes | 718 Views
Nutrition and ergogenic aids : Preventing infection and enhancing performance Dr Gary Brickley Masters Swimming Event May 2006. Accredited Exercise physiologist Ph.D. in muscle metabolism, MSc. in cardiology Lecturer in physiology and sports nutrition
E N D
Nutrition and ergogenic aids : Preventing infection and enhancing performance Dr Gary Brickley Masters Swimming Event May 2006
Accredited Exercise physiologist Ph.D. in muscle metabolism, MSc. in cardiology Lecturer in physiology and sports nutrition Coaching consultant GB Paralympic cycling team Consultant to triathlon
Overview Nutrition for health Energy demands of swimming Exercise and infection Ergogenic aids for training Ergogenic aids for performance
Energy demands for sprint swimming Explosive power Large lean body mass High levels of resistance training Protein for recovery High phosphocreatine requirement Ability to buffer lactic acid
Energy demands for (ultra) endurance swimming Efficient fat burning Need to use carbohydrates efficiently and refuel Considerations during event –hydration , palatability Blood pressure during ultra performance
Nutrition of the ultimate swimming performer Ability to match the demands of training Ability to recover from high intensity exercise Perfect tapering of diet and training Excellent immune function Focussed nervous energy
Questions To Ask? • Who needs to supplement? • When do you recommend a supplement? • How much do I need? • What do you recommend? • Can you get too much?
Review of ergogenic aids used by GB cycling team
Overview of Cr metabolism • Daily requirement of Cr is 2 g/day • Cr is excreted in urine as creatinine • 1 g/day from diet • 1 g/day from endogenous production - liver, pancreas, kidneys • 95% of Cr stores are found in muscle • 35% as Cr, 65% as CrP • Total Cr stores = Cr + CrP
Side effects • Anecdotal evidence of muscle cramps and strains • gastrointestinal disturbances if Cr is ingested un-dissolved • ingestion of poor quality Cr may be toxic • increase body weight (1-2 kg)? - may be an advantage if it is an increased muscle mass (power to weight ratio)
Sodium Bicarbonate (Baking soda)
Proposed ergogenic benefit • Increased release of lactate and H+ from muscle • Delayed onset of fatigue • Improved high intensity exercise performance
Benefits for swimmers • Need to load 0.3g/kg 60-90 min before exercise mixed with 1-2 litres of water • Evidence of benefits from 1 min to 3 min events • Facilitates blood in coping with changes in acidity
Hazards • Flatulence • Bloating • Diarrhoea • Vomiting
Issues of Caffeine Use • Caffeine is no longer a banned substance in competitive sports • With habitual caffeine users there may be a reduced ergogenic effect. • Side-effects, particularly with large doses in non-habituated caffeine individuals, can includes headaches, insomnia, restlessness etc.
Making CHO drinks • A 6-8% solution appears to be the most effective for hydration and supply of CHO. • To make a 500mL bottle of 6% CHO. • 6/100 x 500mL = 30mL or 30g CHO is needed • Must use a no calorie drink as placebo
Protein supplementation Assists in recovery Ideally taken soon after exercise New evidence of improved sleep patterns emerging Check the amino acid content
Prolonged (> 90 minutes) hard bouts of exercise depress immune function Blood glucose Muscle glycogen Interleukin-6 Stress hormones Free radicals Depression of immune cell functions
Depressed immunity may increase risk of picking up colds and flu Increased risk of infection Depression of immune cell functions
Carbohydrate feeding during exercise prevents the development of hypoglycaemia and reduces IL-6, adrenaline and cortisol responses and thus helps to prevent exercise-induced immune function depression
Vitamin C supplementation and post-race incidence of URTI % of participants reporting symptoms of URTI within 14 days of an ultramarathon race 68% 33% Peters et al 1993 Am J Clin Nutr 57: 170-174
Summary: Anti-oxidants, exercise and immune function • Chronic supplementation with Vitamin C (but not other anti-oxidants) is associated with a lower incidence of URTI following an ultramarathon • Acute supplementation with Vitamin C increases plasma antioxidant capacity but does not influence cortisol response to exercise • Chronic supplementation with Vitamin Cincreases plasma antioxidant capacity and attenuates the cortisol response to exercise • Possible beneficial effects of more potent antioxidants? (e.g. polyphenols in grape juice, dark chocolate)
Other dietary immunostimulants • Glutamine or BCAA • Zinc • Echinacea • -6 fatty acids • Prebiotics • Probiotics • Bovine colostrum Evidence that any of these supplements can limit or prevent exercise-induced immunodepression is weak or lacking
Practical strategies for preventing infection in athletes (1) Minimise the potential for transmission of infectious agents:- • Avoid sick people • Good personal hygiene (wash hands and brush teeth regularly) • Never share drink bottles etc • Avoid getting a dry mouth • Awareness of vulnerability after training or competition
Practical strategies for preventing infection in athletes (2) Minimise the chances of developing depressing the immune system:- • Avoid very prolonged training sessions (> 2 hours) • Monitor mood, fatigue and soreness • Get adequate sleep (at least 6 h) • Eat a well balanced diet with sufficient carbohydrate, protein and micronutrients (and increase antioxidants) • Consume 6% carbohydrate drinks during and after prolonged workouts (2.5 ml/kg every 20 minutes) • Consider vaccination against influenza • Control rate of progression of training (< 20% per week) • Vary training; avoid monotony; include recovery days
Practical strategies for preventing infection in athletes (3) Training and infection:- • Exercise tolerance will be reduced during infection • Exercising with an infection may increase the severity or duration of the illness • Do not train with a fever or with symptoms below the neck (swollen glands, muscle/joint aches, cough) • Do not resume training at the same level • Isolate infected team members from others
Thanks for your attention. Any questions?
Case Studies How may you alter someone’s nutrition who; Is consistently underperforming Has a history of overtraining Who fades near the end of their 400m event Never matches race performance to training