9 13 13 Kin 110 lecture Can you design a study that answers an important question is doable in a reasonable time for reasonable amount of o Heart disease example o Yes as long as you can break it up into smaller studies with each answering part of the question in order to accumulate enough evidence to answer you big question Take home messages o We don t know as much as we think we do o Definitive answers are difficult to obtain o Science is always in transition can t worry about the fact that caffeine is good tomorrow its bad Be weary of consistant data from multiple data Isn t always easy to do We rely on others to do it for us Challenges to doing research that gives clear definitive information o How does info get transmitted to public o Does the public read any of these Public reads translated studies by media to form average people can understand o Myth about exercise in time magazine by john cloud o What gets lost What gets added o Does public get right message How are we doing so far o Metabolism is the sum total of energy transformation reactions in the body TRUE catabolism breaking down anabolism building up o Diet is defined as the average nutrient intake over time o Person in energy balance eats same number of kcal day FALSE eating same number of calories you are expending Body extracts energy from stored reserves to accomplish tasks requiring energy o Basic maintenance energy required to keep heart beating lungs respiring ions across membranes o Energy to do nothing and be alive Energy required to do these tasks is BMR basal metabolic rate or RMR resting metabolic rate same thing more or less RMR can be biggest portion of energy output depending on how active you are o 1 kcal min 1440 kcal day o range from 1000 1800 90 lbs 180 lbs What determines RMR o Age o Gender o Activity o Genetics o Biggest contributor is muscle mass o More muscle mass higher metabolic rate o Fat is inactive tissue o Muscle is highly active tissue o Higher number of calories to be at rest Harris benedict equation for RMR o Men vs women o 9 56 63 6 1 85 175 26 4 68 21 608 324 98 834 2 processes of digesting and absorbing food requires energy o Called diet induced thermogenesis DIT or thermic effect of food o Energy for DIT is about 10 of total energy needs o Eat 2400 kcal day DIT is about 240 kcal Why is difficult to lose weight by cutting food intake o If energy intake goes down so does DIT o Decrease from 2400 kcal day to eating 1000 kcal day the DIT goes from 240 100 o Meaning your daily output is 140 kcal 3 Physical activity o most variable o major difference between people in energy output due to physical activity 0 2000 kcal day energy required for physical activity can vary from 0 to over 2000 kcal day energy must be in form adenosine triphosphate ATP to be used for metabolism o ATP is often called energy currency of the cell o Only ATP can be used for muscles to contract send ions across membranes Every day body supply of ATP is recycled 5000 times o Other stored fuels CHO PRO FAT used to resynthesize ATP Analogy gumball machine o Only takes quarters to take gumballs o Human only takes CP ATP o 1 CHO Glycogen Glucose takes longer than quarters to break down o 100 Fat stored fat takes longer than 1 to break down o Visa Card Protein functional will lose muscle mass if you don t pay it back Can t give it away very long without replacing it o Need to turn the visa 100 and 1 into quarters What determines quantity of energy needed o Rest or exercise o Intensity o Duration o Total energy needed how many ATP required What determines kind of energy required o Intensity o Duration o Availability of stored fuels CHO FAT PRO o What determined stored energy Diet o Nutrition habitual diet pre exercise meal Post exercise nutrition During exercise as well o So energy storage partly determines human athletic performance The other part Capacity to use the energy Determined by physiology Capillaries size Determined by genetics and training
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