Lab Exam 2 Flashcards
non-exercise equations for predicting VO2 max
regression equations based on age, sex, BMI, PA-R (physical activity rating) and PFA (perceived functional ability)
to extrapolate VO2 max based on submax HR, you must use two HR values between:
120 bpm and 70-85% predicted maximal HR
assumptions from estimating VO2 max from submax heart rates
1) linearity of HR-VO2
2) max heart rate can be estimated based on age
3) assumed exercise economy
how to calculate target VO2R
target VO2 R = (exercise intensity) x (VO2 max - VO2 rest) + VO2 rest
calculating target HRR
target HRR = (exercise intensity) x (HRmax - HRrest) + HRrest
american college of sports medicine recommendations for cardiorespiratory endurance exercise
mode: use large muscle groups
frequency: 3-5 days per week
duration: 20-60 minutes
intensity: moderate and/or vigorous exercise
what is upper body obesity described as
android (fat primarily in abdominal region), greater health risk
what is lower body obesity described as
gynoid (fat primarily in hips and thighs) less of health risk
direct body composition assessments
chemical analysis of a cadaver
indirect body composition assessments
derived from direct method (DEXA)
doubly indirect body composition assessments
skinfold method, bioelectrical impedance analysis (BIA)
DEXA differentiates body composition into 3 components
1) mineral-free lean mass
2) fat mass
3) total body mineral stores
does DEXA provide a direct measure of bone strength?
no, DEXA just measures mineral content, which accounts for around 70% of bone strength
MAP formulas
MAP = 1/3(sBP-dBP) + dBP
MAP = cardiac output (Q) x total peripheral resistance (TPR)
core temps above 40 degrees celsius can lead to:
dangerous hyperthermia, heat stroke, heat exhaustion, may denature proteins, enzymes, leading to brain damage or death
core temps below 35 degrees celsius may lead to:
dangerous hypothermia, may cause slowed metabolism and arrhythmias, or death
body heat gain during exercise =
heat produced - heat loss
what does evaporation rate depend on
temperature and relative humidity and amount of skin surface exposed
how much body heat is lost per mL of sweat evaporated
0.58 kcal heat/mL evaporated
if a wet bulb and a dry bulb displayed the same temperature, what could we conclude about humidity?
100% humidity
mechanisms of heat-related exercise fatigue
1) high brain temp reduces neuromuscular drive (reduction in motor unit recruitment)
2) accelerated muscle glycogen metabolism and hypoglycemia (controversial)
3) increased free radical production (damage to muscle contractile proteins)
4) cardiovascular instability
what does heat acclimation/acclimatization require?
exercise in a hot environment
describe the oxygen transport cascade
reduced PiO2 leads to a decrease in the alveolar partial pressure of oxygen (PAO2), which leads to a reduction in the partial pressure of oxygen in arterial blood (PaO2)
physiological responses to acute altitude exposure
decreased SaO2, decreased VO2 max, increased resting and submax HR, increase ventilation, increased fat utilization, slight decrease in MAP
how do hypoxic conditions affect the ventilatory and lactate thresholds?
leftward shift; ventilatory and lactate thresholds are reached at a lower absolute workload
4 potential reasons why measurement of VO2 max could be contraindicated or impractical
1) expensive equipment
2) trained staff
3) time constraints
4) medical considerations
when prescribing exercise using a predicted max heart rate, how would relative intensity of submaximal exercise be affected if max heart rate was overestimated?
if max heart rate was overestimated, the relative intensity of submaximal exercise would also be overestimated. this is because the predicted heart rate at the given relative intensity will be higher than the heart rate should be at the relative intensity with the individual’s actual HRmax
4 potential sources of error for BMI and waist circumference measurements
1) measurement technique
2) equipment calibration
3) inhalation vs. exhalation
4) most recent meal
4 potential sources of error for skinfold measurements
1) technician training
2) proper equation selection
3) measurement technique
4) calipers
at a given BMI, why does elevated waist circumference confer increased risk of chronic disease?
an elevated waist circumference is indicative of increase risk of chronic disease independent from BMI because fat located in the abdominal region is associated with a greater health risk than peripheral fat
T or F: an individual with a BMD t-score of -2.6 is deemed to have osteoporosis by WHO criteria
True
T or F: you can be certain that an individual with a z-score of 0 does not have osteoporosis
False
T or F: a subject must reach VO2max for a GXT test to produce beneficial information about cardiovascular health
False
list of normal, good prognosis from a GXT
1) achieve > 80% predicted HRR
2) sBP increases 5-10 mmHg per MET
3) HR Recovery = decreases 12 bpm in 1 min
4) 3 min post-exercise sBP = <90% max sBP
5) normal cardiac rhythms
abnormal/poor prognosis from a GXT
1) achieve < 80% predicted HRR
2) slow increase or sudden decrease in sBP
3) sBP > 250 mmHg or increased > 140 mmHg from rest
4) dBP increase > 10 mmHg
5) dysrhythmias, ST segment depression/elevation
at what rate should you release air from cuff to obtain an accurate blood pressure measurement
2-3 mmHg per second
what direction should earpieces face when taking BP?
facing away, like a beak
T or F: it is a good idea to place the head of the stethoscope under the blood pressure cuff in the effort to free a hand, eliminate possibility of hearing your own pulse, and ensure the stethoscope head is firmly held flush in the antecubital space
False
what pressure should you inflate the cuff to for a healthy individual?
no more than 200 mmHg or 20 mmHg above estimated systolic BP
how much time should pass between consecutive BP measurements
90-120 seconds
cuff too small effect on sBP
increase 10-40 mmHg
cuff over clothing effect on sBP
increase or decrease 10-40 mmHg
not resting 3-5 mins effect on sBP
increase 10-20 mmHg
legs crossed effect on sBP
increase 5-8 mmHg
back/feet unsupported effect on sBP
increase 5-15 mmHg
patient talking effect on sBP
increase 10-15 mmHg
GXT protocol: how is speed set?
speed set at 70% HRmax
GXT protocol: how long is each stage?
2 minutes
GXT protocol: how much does treadmill grade increase each stage?
2% (2.5% if above 6 mph)
GXT protocol: when is the test complete?
participant reaches volitional fatigue or predetermined HR%
GXT protocol: when is it safe to stop supervising the subject?
when HR returns to roughly 100 bpm
2 mechanisms by which increased sympathetic activity may increase oxygen delivery with acute high-altitude exposure
1) increased vasodilation
2) increased cardiac output
(3) increased ventilation
(4) increased submax/resting HR
which components of arterial oxygen content would be most affected by blood doping?
hemoglobin concentration
which components of arterial oxygen content would be relatively unaffected by blood doping?
SaO2 (arterial hemoglobin saturation) & the amount of O2 dissolved in the plasma
