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Page 1

Concept questions

What are the 3 macronutrients and their fundamental

characteristics? Which are used for energy?

What are the muscle and blood fuel sources respectively?

What is the relationship between exercise intensity and…

Use of fat?

Use of carbs?

What is the relationship between muscle glycogen and exercise

intensity? What effect does that have on muscle glycogen and performance during

exercise?

Describe the 2 different ways in which the liver produces glucose.

How do these processes change with increased exercise intensity? Which one

contributes more glucose at high intensity?

Explain what is occurring in the above graph. What is special

about the first hour of exercise? Why does that occur? (Hint: Think about the

liver).

When is the best time to eat after exercise? Why?

How does muscle protein

synthesis differ when exercising vs. relaxing?

Name the 2 types of

micronutrients and their functions.

Which vitamins are lipid

soluble? Water soluble? How do the characteristics of a lipid vs. water soluble

vitamin differ?

What is glycemic index?

What event occurs after a

pre-exercise carbohydrate meal? If the meal had a lower glycemic index would

the same event occur?

Graph the relationship between

lipolysis (y-axis) and insulin (x-axis).

Graph the relationship

between lipolysis (y-axis) and exercise time (x-axis).

What happens to blood

glucose if a meal is ingested…

More than 4 hours before exercise?

Less than 1 hour before exercise?

What is the benefit of

ingesting carbohydrates during exercise? How much should you eat?

What is BMR? RMR? How are

the 2 related?

Rank these activities from

highest to lowest amount of energy expenditure:

RMR, DIT, Physical Activity

Which form of energy

expenditure changes the greatest on a day-to-day basis?

Page 2

Vocabulary

glucose - blood sugar; comes from digestion in liver(mono)

fructose - sugar in fruits; converted to glucose in the liver(mono)

galactose - combined with glucose to make milk sugar in mammary gland(mono)

sucrose - glucose+fructose; 25% of caloric intake for average american; table sugar (di)

lactose - glucose+galactose; milk sugar only; lactose intolerant= lack "lactase" enzyme (di)

maltose - glucose+glucose; smallest part of diet -- cereal, beer (di)

2 forms of polysaccharides - starch and fiber

starch - storage of CHO in plants; complex carbs; 50% of carb intake; grains, potatoes, corn; amylose+amylopectin

fiber - mostly make up structural components in plans; can't digest!

exercise intensity on muscle fuel source - - high intensity = more carb

- low intensity = more fat

Carbohydrate fuel - 1. blood glucose from liver

2. muscle glycogen

Fat Fuel - 1. plasma free fatty acids (adipose tissue)

2. intramuscular triacylglycerols (IMTG)

Muscle fuel - 1. Muscle glycogen

2. intramuscular triacylglycerols

Blood-borne fuel - 1. plasma free fatty acids (adipose tissue)

2. blood glucose

low intensity vs. high intensity specific fuel sources - -low intensity: lacks muscle glycogen as fuel source so PLASMA FATTY ACIDS

-high intensity: MUSCLE GLYCOGEN!

Can muscle glycogen be transported? - NO! cannot be transported from one muscle to another

Glycogen - - storage of CHO in animals

- long link of glucose molecules

- stored in liver and muscle

- liver glycogen -> blood glucose

- muscle glycogen-> local store of fuel for contraction

glycogen breakdown - 1.glycogenolysis - glycogen -> glucose for fuel

2. glycogen is major source for high intensity

3. hit the wall when run out

muscle glycogen is key for performance - endurance!

CHO DISTRIBUTION: - 1. plasma glucose (16 kcal)

2. liver glycogen (400 kcal)

3. muscle glycogen (1600 kcal)

what is the norm blood glucose level before exercise? - 5 mM -- continues to decrease with exercise

order of energy source during exercise: - 1. muscle glycogen

2. IMTG

3. blood glucose

4. plasma fatty acids

gluconeogensis occurs more than glycogenolysis during exercise. (T or F) - FALSE! break down of glycogen in liver happens way more than generation of glucose from other sources

higher intensities of exercise lead to more glycogenolysis - true

gluconeogenesis - - happens in liver

- lactate can leave muscle and go to liver to be converted to glucose

liver produces 2 times as much glucose in intense exercise vs. rest (T OR F) - TRUE!

does glucose uptake increase or decrease with increase exercise intensity - increase!

ROLE OF CHO IN BODY - - brain uses almost only glucose for fuel

- primary fuel for muscles during exercise

- difficult to maintain intensity with depleted sugar levels

LIPIDS - - 3 kinds: simple, complex, and derived

- dietary fat = triglycerides

- same elements as carbs but linked differently

lipolysis - -triglyceride broken down to release fatty acids for energy

lipase - enzyme needed to break down triglycerides by adding H20

Fatty acids - -chain of C with H attached

- # of C and H determines properties

- saturated and unsaturated

Saturated fatty acids - -NO double bonds: H attached to every possible binding site

- mostly in animal fat,dairy, eggs,

-SOLID @ room temp

Unsaturated fatty acids - -1 or more double bonds

-MONOunsat: 1 double bond: olive, peanut oils

-POLYunsat: more than 1 double: sunflower, corn, safflower oils

-hydrogenation: ADD H!(remove double bonds) makes spreads -- more unhealthy

-LIQUID @room temp

compound lipids - lipids + other molecules

- phospholipids (lipid and phosphate)--> essential component of cell membrane

- glycolipids (lipid and carbo) --> antibody identification

-lipoproteins (lipid and protein)--> makes lipid water soluble; major form of lipid transport in blood

lipoprotein types - -chylomicrons : packaged triglycerides from diet

-high density lipoproteins (HDL) : good cholesterol

-low density lipoproteins (LDL):bad cholesterol

-very low density lipoproteins (VLDL): mostly triglyceride inside; food goes to liver and cholesterol and tricylglycerol combine to make VLDL (makes more cholesterol if too low)

- NORMAL CHOLESTEROL =200 mg/dl

ADIPOCYTES AND LIPIDS/FA ARE NOT THE SAME THING!!! - true

DISTRIBUTION OF FAT STORAGE - 1. adipose tissue = 108,000 kcal

2. intramuscular tricylglycerols = 2,700 kcal

3. plasma tricylglycerols = 36 kcal

4. plasma FFA =3.6 kcal

is there more lipid or carb storage in muscles? - more kcal of LIPID bc only 2,000 total kcal of glycogen

lipid use during exercise - 1. fat is PRIMARY FUEL at REST/ LOW INTENSITY

2. proportion of energy from fat decreases as exercise intensity increases -- but either way fat use is still very high!!!

contribution of plasma fatty acids and IMTG - - increase intensity = half and half

- decreased intensity = mostly plasma fatty acids

PROTEINS - - examples are hormones, enzymes, transporters, hemoglobin

- metabolism -> protein is constantly "turning over"

---- tissue building= anabolism

---- tissue breakdown=catabolism

what is different between amino acids? - R group!

what is the r group for alanine? - CH3! can also be converted to glucose (pyruvate first) and used in gluconeogensis

what is deamination - nitrogen removed from amino acids; occurs in liver and forms urea

what is transamination - when N2 is removed from one amino acid and passed to another to pass energy

Nitrogen Balance - N intake = N excretion; negative balance = malnourished; positive balance = growth, children, pregnant women

what is the recommended protein intake - 0.8 g/kg of body weight (50-100 g of protein per day)

what kind of issues can excess protein lead to? - kidney and liver problems

Lipid soluble vitamins - ADEK!

- stored, slow turn over (daily ingestion not necessary)

- low fat diet may lead to deficiency

- toxic if have too much

water soluble vitamins - B and C's

- not stored (fast turn over)

- lots are lost in urine

-potency:8-14 hours

-need more frequently

Minerals - -can join with compounds to make proteins (iron in hemoglobin -- need it bc binding site)

Major minerals contribution!

Calcium

sodium

Mg - Ca- muscle contraction, bone formation

Na- nerve function, water and acid/base balance

Mg- protein synthesis

(when in doubt- acid base balance)

Water!

-% of body mass?

-% of muscle mass?

% of Fat mass? - -BM: 40-70%

-MM: 65-75%

-FM: 10%

functions of body water - - lubricates tissues

- transport medium

- cushions and protects

-temperature regulation

transient hypoglycemia - - eating breakfast leads to increased blood glucose, so increased insulin, so increased glucose uptake; so with workout--> more glucose uptake which may lead to crash, but probably not

glycemic index -- high vs. low - value that represents how high a given meal increases blood glucose concentration

- high GI--> immediately released into blood stream --> increased insulin response

- decrease in glucose does not cause fatigue, often unnoticed

relationship of lipolysis and insulin - lipolysis is very SENSITIVE to insulin -- insulin enhances glucose into fat cells

Glycemic index and lipolysis -- - -lipolysis is REDUCED MORE after high glycemic meals than low glycemic meals

PRE-EXERCISE MEAL SUMMARY: - - meals more than 4 hours before exercise leads to INCREASED GLYCOGEN

- meals less than an hour before exercise leads to DECREASED glucose in early exercise for short time and decreased lipolysis after CHO meal

CHO INGESTION DURING EXERCISE -- why does it delay fatigue? - - prevents hypoglycemia

- increase CHO oxidation late in exercise bc can't rely only on fat stores

- DOES NOT spare muscle glycogen to save for later use

recommendations for CHO ingestion during exercise - 30-60 g CHO/hr

Gastric emptying -- what increases or decreases rate? - -increases rate:

-- increased volume

-decreases rate:

-- increase in caloric content

-- increase in solute concentration (osmolality)

-- exercise intensity >75% VO2 max

-- deviations from 7 pH

-- dehydration

fluid absorption -- what affects it - ALL INCREASE INTESTINAL FLUID ABSORPTION:

-low to mod level of glucose and sodium

- hypotonic to isotonic fluids with NaCl and glucose

adequate fluid replacement -- how much CHO needed in drink? - 4%

CHO after exercise - GOAL -- increase muscle glycogen

-highest rate of glycogen synthesis occurs after exercise -- so eat high cho after working out

recommendations for CHO after workout - 500-600 g CHO

what is hyponatremia and who is more likely to get it? - - low sodium in blood; people who are above and below optimal BMI are more likely to have this

components of daily energy expenditure and percentages - - RMR (60-75%)

-DIT (10%)

- physical activity (15-30%)

BMR what is it and how to find it - - sit for 30 min before measuring

-estimates number of calories needed to function

-RMR is less strictly measured than BMR

how much can rigorous exercise increase energy expenditure compared to resting? - 10 times!

physical activity ratio (PAR) - - light work = 3x resting (EE)

- heavy work=6-8x resting

-maximal = >9x resting

metabolic equivalents (MET) - multiple of RMR

- 1 met=3.6 ml/kg/min

-2 mets= 2 rmr

- way to measure energy expenditure not at rest

calorie - quantity of heat necessary to raise the temp of 1 ml of water by 1degree c

-300 calories on food wrapper is really 300 kcal and 300,000 calories

bioenergetics - -converting food to energy

-all forms of energy are interchangeable

-energy transfer occurs by releasing energy trapped in chemical bonds

energy need for bodily work (types of work and examples) - mechanical work - muscle contraction

chemical work-protein synthesis

cell transport work - pump ion across membranes

Who would benefit from a drug that increase ATPase? - -high endurance athletes! may be detrimental bc rigor mortis bc ATPase breaks down the ATP

ATP breakdown reaction - ATP --> ADP + P + energy

what are the cells 2 major energy transforming activities? - 1. take potential energy in food and store in bonds of ATP

2. break down ATP to use energy for biological work

ATP supply - -small quantity so need to continually resynthesizes

- extreme exercise conditions lead to levels in skeletal muscle to decrease

-stores only 80-100 g of ATP while resting

Phosphocreatine (PcR) - energy for ATP resynthesis from anaerobic splitting of phosphate from PCR

-CELLS STORE ABOUT 4-6 TIMES MORE PCR THAN ATP!!!

glycolysis energy investment and generation - investment : 2 ATP

generation: produces ATP, NADH, pyruvate and/or lactate

energy release from macronutrients - Stage 1: digests/absorbs macronutrients

Stage 2: degrades all into acetyl-CoA

Stage 3: acetyl CoA degrades into H20 and CO2 to make ATP

energy release from CHO - -complete oxidation of glucose molecule yields 30-32 ATP

-LOTS of energy from breaking down glucose dissipates as heat

glycolysis: two forms of CHO breakdown - -aerobic: pyruvate is end product-- SLOW process

-anaerobic: lactate formation -- RAPID process

lactic acid stays in same muscle(T orF) - FALSE! lactic acid spreads to all muscles and can be measured anywhere

when does pyruvate convert to lactate? - 2 molecules of pyruvate from anaerobic breakdown of glycolysis. lactate forms when NADH oxidation doesn't keep pace with formation in glycolysis

-- aka during exercise, not enough O2 so pyruvate takes H+ from NADH and forms lactate and NAD+ to allow glycolysis to continue

energy metabolism regulation (enzyme inhibitors and activators) - INHIBITORS: ATP and NADH

ACTIVATORS: ADP and NAD+

what has the greatest effect on rate limiting enzymes that control macronutrient energy metabolism? - cellular ADP concentration!

lipogenesis - formation of FAT when glucose and protein aren't used for energy

fats require intermediates generated in carb breakdown for their continual catabolism for energy - true

what breakdown provides more power? (fat or carb) - carb breakdown!! so depleting muscle glycogen decreases a muscles max aerobic power output

Acetyl CoA - -common point where rules meet at start of ATP production

-glucose>pyruvate>acetyl coA

-fatty acid>fatty acetyl coA>acetyl coA

-protein>AA> acetyl CoA

what are products of krebs cycle and what is it for? - completes oxidation of substrates for oxidative phosphorylation; produces 3 NADH and 1 FADH

cellular oxidation - mitochondria remove electrons from hydrogen and eventually pass them to O2

electron transport chain - - final pathway where electrons from Hydrogen are passed to O2

-mitochondrial O2 is driving source of change bc final acceptor to combine with hydrogen to form water

-provides 95% of all cellular energy

oxidative phosphorylation - synthesizes ATP by transferring electrons from NADH and FADH2 to O2

-more than 90% of ATP synthesis takes place in respiratory chain

-reducing agents (NADH AND FADH) donate electrons to form gradient

- 2.5 ATP for every NADH and 1.5 ATP for every FADH

hypothesis for ATP formation - electron transport chain results in pumping H+ions through inner membrane space to inter membrane space--> creates gradient so that H+ diffuses back to cytosol where ADP and P can then combine to form ATP(through ATP synthase)

efficiency of oxidative phosphorylation (GREAT EFFICIENCY! - yields 32 ATP from 1 mol of glucose

-34% efficiency of aerobic respiration --66% energy released as heat!!!! -- more over weight people would benefit from reduced efficiency

ATP at rest and during exercise - 500:1 ATP:ADP ration -- with exercise.. ratio gets much smaller but overall ATP DOES NOT CHANGE MUCH!

can all forms of energy transfer occur at once during exercise? - YES!!! just may not play a big role

ATP-PC immediate energy - limited storage of high energy phosphates

ratio of PCR to ATP at rest: 5:1

nuclear resonance imaging(NMR) - used to measure number of high energy phosphates

glycolysis for short term energy - -forms ATP rapidly, but exhausts quicker

- 2 ATP/mol of glucose

Lactate threshold - - low tissue O2 --> reliance on glycolysis --> activation of fast twitch muscle fibers--> reduced lactate removal

blood lactate potential uses - - lactate shuttle -- converted to pyruvate and oxidized as energy in diff cell

-gluconeogenesis -- converted back to glucose in liver in cori cycle

cori cycle - conversions of glucose to lactate from muscle to liver

O2 consumption with exercise - O2in-O2out =O2 consumption

-O2 MEASURED at lung not tissues but O2 USED in tissues NOT LUNG

steady state - when O2 demand is met by O2 delivery

- no lactate accumulation

VO2 and exercise intensity - -as VO2 increases, EE increases

- VO2 max - point where VO2 no longer increases with increasing intensity

oxygen deficit - - transition from rest to exercise -- takes time for O2 to reach steady state

- difference between total O2 consumed during exercise and total O2 that would have been consumed if VO2 reached steady state immediately

oxygen debt - -measured O2 in recovery - theo resting O2 concentration

- pay back for metabolic alterations to get body back to pre-exercise condition

-larger recovery with increased intensity

-most lactate is oxidized for energy **

EPOC (excess postexercise O2 consumption) - may be due to ventilation, hormones, circulation, temp, reloading blood with O2

direct vs indirect calorimetry - -direct: subject enclose din container and measures heat production

-indirect: uses measurements of VO2 to asses energy expenditure -- Vexpired LESS THAN Vinspired l VO2= o2 inspired-o2 expired

Respiratory quotient (same as respiratory exchange ration -RER) - -shows substrate utilization

- RQ range =.7-1.0

-CARB: 1.00 ; all fat = 0.70

-combination of use =.85

RER > 1 ..how? - happens at HIGH INTENSITY

-- happens bc excess of CO2 to compensate for lactic acid accumulation--> SO CO2 is not from substrate but is from acid base balance

doubley labeled water technique - - goal is to calculate O2 consumption over time to estimate energy expenditure (days)

- can calculate from CO2 production

DIT! - 1)obligatory thermogenesis : energy needed to digest food

2) facultative thermogenesis : related to increased activation of sympathetic nervous system which can lead to an increase in energy metabolism

NON-exercise activity thermogenesis (NEAT) - -spontaneous activity (fidget, twitch, pacing)

-lean individuals are usually more fidgety

-increased neat--> decreased fat gain

what climates increase BMR - cold and hot! cold more

THE BIGGEST LOSER! -- what was it measuring? and how? - - wanted to see if this program helped preserve fat free mass and maintain resting metabolic rate

-RMR went down but fat loss was mostly not lean mass

-measured TDEE and measured RMR by indirect calorimetry

lipolysis and glucose relationship - increased glucose in blood --> increased insulin --> lipolysis DECREASES because doesn't want to break back down after just bringing it from the blood