VO2max and Ventilatory Threshold

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VO2max and Ventilatory Threshold

• PED 5700
• Lab 1

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Ventilation Threshold
CO2 from Krebs cycle and buffering lactic acid
stimulate ventilation even faster
CO2 from Krebs cycle stimulates ventilation
Aerobic
Aerobic and Anaerobic
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Determining Ventilation Threshold
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Determining Ventilation Threshold
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Ventilation Threshold

• What can it be used for?

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(No Transcript)
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Lab Report

• Purpose
• Methods
• Results
• Discussion

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Purpose

• To determine the aerobic fitness level and
  anaerobic threshold.

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Methods

• Measurements
• VO2 ml/min
• VO2/KG ml/kg/min
• VCO2
• R
• VE
• VO2max
• HR (?)

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Methods

• VO2 and Ventilation were measured from expired
  gases analyzed with an open circuit, online
  metabolic system (SensorMedics 2900) during a
  graded treadmill exercise test.

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Methods

• VO2max Criteria
• Leveling off of VO2, despite and increase in
  workload
• R value greater than 1.15
• Within 10 beats of age predicted maximum heart
  rate
• Post-exercise blood lactate greater than 8
  mmol/liter

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Methods

• Ventilation Threshold Criteria
• Tvent Breakpoint when ventilation (VE) is
  plotted over oxygen uptake (VO2)

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Results

• VO2max
• Ventilation threshold
• Target heart rate based on ventilation
  (anaerobic) threshold

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Results

• Determine VO2max
• Determine ventilation threshold
• Plot VE over VO2 on a separate graph (see later
  slides)
• From the graph, determine the ventilatory or
  anaerobic threshold and the heart rate at the
  anaerobic threshold

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Discussion
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Lab Reports

• Write up your results.
• Include an introduction, methods, results, and
  discussion sections.
• Include the data and the graph in the results
  section along with what other important data you
  feel was gained from the test
• Discuss the findings (what they mean, how they
  can be put to use, etc.)
• Lab reports are due 2/14/06.

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Validity and reliability of combining three
methods to determine ventilatory threshold
STEVEN E. GASKILL BRENT C. RUBY AVA J. WALKER
OTTO A. SANCHEZ ROBERT C. SERFASS ARTHUR S.
LEON MEDICINE AND SCIENCE IN SPORTS AND EXERCISE
2001331841-1848 Purpose This research was
undertaken to validate a combination of
methodologies to determine ventilatory threshold
(VT). Methods Three methods were used
individually and then combined to determine VT as
follows 1) ventilatory equivalencies, 2) excess
CO2 production, and 3) a modified V-slope method.
Three groups of participants-endurance athletes
(N 132), healthy, aerobically active adults (N
31), and healthy, sedentary/low-active adults
(N 22)-were independently evaluated for VT and
compared with the criterion standard lactate
threshold (LT) defined as the first rise in blood
lactate with increasing intensity of exercise.
Results VT and LT were significantly
correlated using the combined VT method within
each study group (r 0.98, 0.97, and 0.95,
respectively P lt 0.001). Mean O2 values at VT
and LT were not significantly different between
the three groups (P gt 0.20). The combined method
improved the determination rate of VT and reduced
the standard deviation of the LT - VT difference
by 80-170 over the individual methods. During
test-retest procedures O2lt and O2vt determined
by the combined method met criteria demonstrating
further reliability. Conclusion The combined
method to determine VT is valid and reliable
across a wide fitness range in healthy
individuals and improves the determination rate
and accuracy of VT determination over the use of
single methods.
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CHEATHAM, C. C., A. D. MAHON, J. D. BROWN, and D.
R. BOLSTER. Cardiovascular responses during
prolonged exercise at ventilatory threshold in
boys and men. Med. Sci. Sports Exerc., Vol. 32,
No. 3, pp. 1080-1087, 2000. Purpose The purpose
of this study was to examine the cardiovascular
responses during prolonged exercise in boys and
men at an intensity set relative to ventilatory
threshold (VT). Methods Eight boys (10-13 yr)
and 10 men (18-25 yr) completed an orientation
trial, a maximal exercise test, and a 40-min
submaximal exercise bout at an intensity equal to
the VO2 at VT (  64.5 VO2max). Results Heart
rate (HR) was higher and stroke volume (SV) was
lower in the boys compared with the men (P  
0.05). From 10 to 40 min, HR significantly
increased 9.5 and 13.6 and SV significantly
decreased 8.8 and 11.6 in the boys and men,
respectively. Despite the tendency for the
changes in HR and SV to be greater in the men,
the group-by-time interaction was not
significant. Cardiac output was greater in the
men (P   0.05) but remained constant over time
(P gt 0.05). In men, mean arterial blood pressure
was higher (P   0.05) and decreased 4.2 over
time. In boys, mean arterial blood pressure
remained constant, which resulted in a
significant group-by-time interaction. Total
peripheral resistance (TPR) was significantly
higher in the boys and remained constant over
time (P gt 0.05). From 0 to 40 min, the decrease
in plasma volume was significantly greater in the
men (-10.2) than the boys (-5.7) but was
unrelated to the changes in SV in either group (P
gt 0.05). Conclusion In conclusion, the
cardiovascular responses during prolonged
exercise are similar in boys and men, although
there is a tendency for the magnitude of
cardiovascular drift to be greater in the men.