Quiz 4

Maximal O2 consumption

Maximum amount of O2 consumed per minute

Lungs take O2 and transfer it to

blood

Heart pumps

blood carrying O2 to working muscles (limiting factors)

Skeletal muscles

cells to extract & utilize O2 from the blood (AVO2 difference)

VO2 max =

HR max * SV max (alpha - v) * O2

Fick equation

VO2 max expressed as

L/min (absolute)

VO2 max is higher in

larger individuals

higher value does not equal (absolute)

higher aerobic fitness

Relative VO2 max is expressed as

ml/kg/min

Relative VO2 max

considers individual difference based on weight

Relative VO2 max

high value typically equals higher aerobic fitness

Maximal o2 consumption declines

with age

Differences in max aerobic capacity between genders are explained

by differences in body mass

If VO2 max is corrected for weight

difference becomes smaller

If VO2 is corrected for FFM

difference becomes smaller/disappears

VO2 max is a

graded test

You can reach VO2 max

within 8-12min

A plateau in Vo2 with increases in ______ is ideal, but…

work rate, but occurs in <50% of subjects tested

HR within +- 10bpm of

age predicted maximum (220-age)

Respiratory Exchange Ratio

(>1.10 at test termination)

Blood lactate concentration

>8.0mmol/L in first 5 min of recovery

Lactate Threshold Definition

point @ which blood lactic acid rises systematically during incremental exercise

Lactate threshold in untrained subjects

appears @ 50-60% Vo2 max

Lactate threshold in trained subjects

appears at higher work rates 65-80% of VO2 max

Lactate threshold (LT) also known as

is called anaerobic threshold, onset of blood lactate accumulation (OBLA)

Blood lactate levels reach 4mmol/L

Low muscle o2 = hypoxia

F

If glycolytic flux > mitochondrial activity

enter fast glycolysis,

NADH in cytoplasm converts pyruvic acid → lactic acid

Recruitment of fast-twitch muscle fibers

LDH enzyme in fast fibers promotes lactic acid formation

Reduced rate of lactate removal from blood

Intracellular Lactate Shuttle

Liver via Cori Cycle

Calorimetry

Amount of heat given off by a reaction

1 kcal

amount of heat required to raise 1L of H2O by 1C

1kcal = ______ calories = ___ calorie

1000, 1

jacket function

keeps heat from escaping

RER

VCO2 / VO2

RER

Fuel utilization

RER = 0.82, ____kcal/LVO2

4.825

As %VO2 max increases, % energy from fat…

decreases

As %VO2 max increases, % energy from Carbs…

increases

Basal Metabolic Rate (BMR)

Minimum energy requirement needed to sustain life processes representing 60-70% of total energy use

BMR (Basal Metabolic Rate) conditions

morning, fully rested, supine

12-18 hours after eating/drinking/smoking (fasted)

No exercise 1-2 days

Free of all psychic/physical disturbances

Resting Metabolic Rate

Estimate of BMR

Measured under less strenuous conditions

4 hour fast

1 hour w/o strenuous activity

Harris-Benedict Equation (kcal/day) in Men

66.5 + (13.8 x BW in kg) +(5 x height in cm) - (6.8 age)

Harris-Benedict Equation (kcal/day) in Women

655.1 + (9.6 x BW in kg) + (1.9 x height in cm) - (4.7 * age)

TDEE (kcal/day)

1279 + (18.3 x BW in kg) + (2.3 x age) - (338 x gender)

gender 1= female, 0 = male

weight in kg

weight (lbs) / 2.2046

Height in cm

height (inches) x 2.54