9.30.13 kin 110 class notes- Finishing up lecture from week before:o Performance limited by CHO People who exercise regularly need CHO in their dieto Assuming value to eat CHO before exercise: what to choose? Are energy bars better than candy bars?- Cliff bar, power bar & snickers have Long shelf life- Table: type kcal ingredients CHO content proteino Cliff bar 240 br. Rice syrup 43 g 10 go Power bar 240 h. fruc. Corn syr. 45 g 9 go Snickers 270 choc. Pnuts, c. syr. 35 4 go Pb. sand. 300 wheat, flour, pb, c. syr. 45 cho 10 g protein- ^Pb sand. has short shelf life- snickers vs. powerbar studyo 6 subjectso tested energy metabolismo maximal exercise test: used cycle ergometer go as long as you possibly cano each subject tried each product on dif. dayso Powerbar exercise… (few days later) snickers exerciseo Snickers exercise… (^) pb exer.o Mean ex. Time difference = 32.17 s Less than 5% chance Close to statistically significant results!o Everyone did more exercise with powerbaro Is powerbar better? Depends…- Intensity- Diet beforehand- Subjects’ metabolism/training (not a big problem) – they switch- Placebo – everyone can tell snickers vs. Powerbaro Biology take home point Foods designed to aid athletic performance (i.e. powerbar) – simple sugars with starches (etc)- Not necessarily a good part of overall diet- Probably not something you want to eat on a daily basis- Today’s lecture topic:- More dietary CHO will raise glycogeno Less evidence that more dietary CHO increases performanceo Alternative to higher glycogen?o Consuming CHO during exercise (not beforehand)- Cho intake and performanceo Ex. Marathon runners – intensity and timeo Endurance performanceo What is it?o Extended period of time – distance running aerobic oxidative examples: rowing, running, cycling 10-15 mins ++- common test:o how long can you exercise at max intensity?o VO2 max: maximal O2 consumptiono Aerobic capacityo Depends on ability of heart to deliver O2 and muscles to use it- Determinate of Vo2 maxo Lung capacity doesn’t mattero Smokero Cardiovascular diseaseo Heart diseaseo Ageo Fitness levelo Gender- Endurace athletes have high Vo2 max levels- Vo2 max measured by exercising at increasing intensityo Oxygen uptake mL/kg/min vs. running speed (mph)o Reaches a max point- Exercise at some % of maximal oxygen consumption intensity usually between 50% Vo2 max (60-80% of heart rate)o Above 80% - higher than that and it becomes anaerobic- Coyle et al (1983)o Vo2 max vs time to fatigue o Cho delays fatigueo Exercise longer at same intensityo +33 mins vs placeboo 126 mins-158 minso enormous effect- CHO:o How much?o Sugars?o Form?o Concentration?o
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