Obtaining a formula that improves maximum oxygen consumption estimation in cycle ergometer exercise tests

Background Assessment of peak oxygen consumption (V̇o2peak) using traditional modes of testing such as treadmill or cycle ergometer can be difficult in individuals with stroke due to balance deficits, gait impairments, or decreased coordination. Objective The purpose of this study was to quantitatively assess the validity and feasibility of a modified exercise test using a total-body recumbent stepper (mTBRS-XT) in individuals after stroke. Design A within-subject design, with a sample of convenience, was used. Participants Eleven participants (7 male, 4 female) with a mean of 40.1 months (SD=32.7) after stroke, a mean age of 60.9 years (SD=12.0), and mild to severe lower-extremity Fugl-Myer test scores (range=13–34) completed the study. Methods Participants performed 2 maximal-effort graded exercise tests on separate days using the mTBRS-XT and a cycle ergometer exercise protocol to assess cardiorespiratory fitness. Measurements of V̇o2peak and peak heart rate (peak HR) were obtained during both tests. Results A strong relationship existed between the mTBRS-XT and the cycle ergometer exercise test for V̇o2peak and peak HR (r=.91 and .89, respectively). Mean V̇o2peak was significantly higher for the mTBRS-XT (16.6 mL×kg−1×min−1[SD=4.5]) compared with the cycle ergometer exercise protocol (15.4 mL×kg−1×min−1 [SD=4.5]). All participants performed the mTBRS-XT. One individual with severe stroke was unable to pedal the cycle ergometer. No significant adverse events occurred. Conclusion The mTBRS-XT may be a safe, feasible, and valid exercise test to obtain measurements of V̇o2peak in people with stroke. Health care professionals may use the mTBRS-XT to prescribe aerobic exercise based on V̇o2peak values for individuals with mild to severe deficits after stroke.

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Cardiovascular responses to treadmill and cycle ergometer exercise in children and adults

Journal of Applied Physiology ◽

10.1152/jappl.1997.83.3.948 ◽

1997 ◽

Vol 83 (3) ◽

pp. 948-957 ◽

Cited By ~ 77

Author(s):

Kenneth R. Turley ◽

Jack H. Wilmore

Keyword(s):

Stroke Volume ◽

Peripheral Resistance ◽

Cardiovascular Responses ◽

Cycle Ergometer ◽

Left Ventricular ◽

Absolute Amount ◽

Exercise Tests ◽

Exercise Modality ◽

Cycle Ergometer Exercise ◽

Ergometer Exercise

Turley, Kenneth R., and Jack H. Wilmore. Cardiovascular responses to treadmill and cycle ergometer exercise in children and adults. J. Appl. Physiol. 83(3): 948–957, 1997.—This study was conducted to determine whether submaximal cardiovascular responses at a given rate of work are different in children and adults, and, if different, what mechanisms are involved and whether the differences are exercise-modality dependent. A total of 24 children, 7 to 9 yr old, and 24 adults, 18 to 26 yr old (12 males and 12 females in each group), participated in both submaximal and maximal exercise tests on both the treadmill and cycle ergometer. With the use of regression analysis, it was determined that cardiac output (Q˙) was significantly lower ( P ≤ 0.05) at a given O2 consumption level (V˙o 2, l/min) in boys vs. men and in girls vs. women on both the treadmill and cycle ergometer. The lower Q˙ in the children was compensated for by a significantly higher ( P ≤ 0.05) arterial-mixed venous O2difference to achieve the same or similarV˙o 2. Furthermore, heart rate and total peripheral resistance were higher and stroke volume was lower in the children vs. in the adult groups on both exercise modalities. Stroke volume at a given rate of work was closely related to left ventricular mass, with correlation coefficients ranging from r = 0.89–0.92 and r = 0.88–0.93 in the males and females, respectively. It was concluded that submaximal cardiovascular responses are different in children and adults and that these differences are related to smaller hearts and a smaller absolute amount of muscle doing a given rate of work in the children. The differences were not exercise-modality dependent.

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Exercise-induced lymphocyte apoptosis attributable to cycle ergometer exercise in endurance-trained individuals

Applied Physiology Nutrition and Metabolism ◽

10.1139/h09-018 ◽

2009 ◽

Vol 34 (4) ◽

pp. 603-608 ◽

Cited By ~ 4

Author(s):

James Wilfred Navalta ◽

Brian Keith McFarlin ◽

Thomas Scott Lyons ◽

John Clifton Faircloth ◽

Nicholas T. Bacon ◽

...

Keyword(s):

Cell Death ◽

Oxygen Consumption ◽

Human Lymphocytes ◽

Cycle Ergometer ◽

Treadmill Running ◽

Peak Oxygen Consumption ◽

Lymphocyte Apoptosis ◽

Cycle Exercise ◽

Cycle Ergometer Exercise ◽

Ergometer Exercise

Exercise as a stimulus to induce lymphocyte apoptosis remains controversial. Differences may be due to participant fitness level or the methodology of assessing cell death. Another important issue is the mode of exercise used to induce physiological changes. Treadmill exercise typically induces significant apoptosis in human lymphocytes; however, the effect of cycle exercise is less clear. The 2 main purposes of this study were to assess if cycle ergometer exercise induces similar changes in apoptosis, and to further characterize the morphological method of assessing cell death. Endurance athletes (n = 10; peak oxygen consumption = 55.1 mL·kg–1·min–1) completed a 60-min ride on a cycle ergometer at ~80% peak oxygen consumption. Blood samples taken before (PRE) and after (POST) exercise were used to make blood films for apoptotic analysis via the morphological technique. A significant increase was observed in the apoptotic index following cycle exercise (PRE = 7.3 ± 2%, POST = 12.9 ± 2%; p < 0.01). On average, it took 42 ± 9 min to read PRE sample slides, which was significantly longer than the 27 ± 4 min needed for POST slides (p < 0.01). To our knowledge, this study is the first to report that exercise on the cycle ergometer produces changes in lymphocyte apoptosis. The values measured during this study were about 20% lower than those we have observed following treadmill running, which may be explained by differences in active muscle mass and the resultant physiological stress between the 2 exercise modes. It is likely that cycling may result in reduced immunosuppression, compared with running at the same intensity.

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Acid-base regulation during exercise and recovery in humans

Journal of Applied Physiology ◽

10.1152/jappl.1992.72.3.954 ◽

1992 ◽

Vol 72 (3) ◽

pp. 954-961 ◽

Cited By ~ 51

Author(s):

W. Stringer ◽

R. Casaburi ◽

K. Wasserman

Keyword(s):

Respiratory Acidosis ◽

Normal Subjects ◽

Cycle Ergometer ◽

Moderate Intensity ◽

Moderate Intensity Exercise ◽

Exercise Tests ◽

Cycle Ergometer Exercise ◽

Arterial Ph ◽

Ergometer Exercise ◽

Exercise In Humans

Arterial pH, PCO2, standard bicarbonate, lactate, and ventilation were measured with a high sampling density during rest, exercise, and recovery in normal subjects performing upright cycle ergometer exercise. Three 6-min constant-work exercise tests (moderate, heavy, and very heavy) were performed by each subject. We found a small respiratory acidosis during the moderate-intensity exercise and an early respiratory acidosis followed by a metabolic acidosis for the heavy- and very-heavy-intensity exercise. During recovery, arterial pH rapidly returned to the preexercise value for the moderate-intensity work. However, arterial pH decreased further during the first 2 min of recovery for the heavy- and very-heavy-intensity work, before a slower return toward the resting values. We conclude that arterial acidosis is the consistent arterial pH reaction for moderate-, heavy-, and very-heavy-intensity cycle ergometer exercise in humans and that this acidosis is blunted but not eliminated by the ventilatory response. During recovery, the return to resting arterial pH and PCO2 and standard bicarbonate appears to be determined by the rate of lactate decline.

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Mediation of reduced ventilatory response to exercise after endurance training

Journal of Applied Physiology ◽

10.1152/jappl.1987.63.4.1533 ◽

1987 ◽

Vol 63 (4) ◽

pp. 1533-1538 ◽

Cited By ~ 68

Author(s):

R. Casaburi ◽

T. W. Storer ◽

K. Wasserman

Keyword(s):

Endurance Training ◽

Venous Blood ◽

Normal Subjects ◽

Cycle Ergometer ◽

Work Rate ◽

Exercise Tests ◽

Average Decrease ◽

Cycle Ergometer Exercise ◽

Ergometer Exercise ◽

The Difference

To investigate the mechanism by which ventilatory (VE) demand is modulated by endurance training, 10 normal subjects performed cycle ergometer exercise of 15 min duration at each of four constant work rates. These work rates represented 90% of the anaerobic threshold (AT) work rate and 25, 50, and 75% of the difference between maximum O2 consumption and AT work rates for that subject (as determined from previous incremental exercise tests). Subjects then underwent 8 wk of strenuous cycle ergometer exercise for 45 min/day. They then repeated the four constant work rate tests at work rates identical to those used before training. During tests before and after training, VE and gas exchange were measured breath by breath and rectal temperature (Tre) was measured continuously. A venous blood sample was drawn at the end of each test and assayed for lactate (La), epinephrine (EPI), and norepinephrine (NE). We found that the VE for below AT work was reduced minimally by training (averaging 3 l/min). For the above AT tests, however, training reduced VE markedly, by an average of 7, 23, and 37 l/min for progressively higher work rates. End-exercise La, NE, EPI, and Tre were all lower for identical work rates after training. Importantly, the magnitude of the reduction in VE was well correlated with the reduction in end-exercise La (r = 0.69) with an average decrease of 5.8 l/min of VE per milliequivalent per liter decrease in La. Correlations of VE with NE, EPI, and Tre were much less strong (r = 0.49, 0.43, and 0.15, respectively).

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