scholarly journals Oxygen Cost of Recreational Horse-Riding in Females

2015 ◽  
Vol 12 (6) ◽  
pp. 808-813 ◽  
Author(s):  
Louisa Beale ◽  
Neil S Maxwell ◽  
Oliver R Gibson ◽  
Rosemary Twomey ◽  
Becky Taylor ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Cycle Ergometer ◽  
Peak Oxygen Consumption ◽  
Moderate Intensity ◽  
Oxygen Cost ◽  
Metabolic Demand ◽  
Moderate Intensity Exercise ◽  
The Public ◽  
Horse Riding ◽  
Ergometer Exercise

Background:The purpose of this study was to characterize the physiological demands of a riding session comprising different types of recreational horse riding in females.Methods:Sixteen female recreational riders (aged 17 to 54 years) completed an incremental cycle ergometer exercise test to determine peak oxygen consumption (VO2peak) and a 45-minute riding session based upon a British Horse Society Stage 2 riding lesson (including walking, trotting, cantering and work without stirrups). Oxygen consumption (VO2), from which metabolic equivalent (MET) and energy expenditure values were derived, was measured throughout.Results:The mean VO2 requirement for trotting/cantering (18.4 ± 5.1 ml·kg-1·min-1; 52 ± 12% VO2peak; 5.3 ± 1.1 METs) was similar to walking/trotting (17.4 ± 5.1 ml·kg-1·min-1; 48 ± 13% VO2peak; 5.0 ± 1.5 METs) and significantly higher than for work without stirrups (14.2 ± 2.9 ml·kg-1·min-1; 41 ± 12% VO2peak; 4.2 ± 0.8 METs) (P = .001).Conclusion:The oxygen cost of different activities typically performed in a recreational horse riding session meets the criteria for moderate intensity exercise (3-6 METs) in females, and trotting combined with cantering imposes the highest metabolic demand. Regular riding could contribute to the achievement of the public health recommendations for physical activity in this population.

Peripheral Chemoreflex Drive in Moderate-Intensity Exercise

1996 ◽  
Vol 21 (4) ◽  
pp. 285-300 ◽  
Author(s):  
Claudette M. St. Croix ◽  
David A. Cunningham ◽  
Donald H. Paterson ◽  
John M. Kowalchuk
Keyword(s):  
Peak Level ◽  
Cycle Ergometer ◽  
Open Loop ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Peripheral Chemoreceptor ◽  
Carotid Bodies ◽  
Ergometer Exercise ◽  
End Tidal ◽  
Peripheral Chemoreflex

The purpose of this study was to measure the contribution of the peripheral chemoreceptor (pRc) to [Formula: see text] during the steady-state of moderate-intensity cycle ergometer exercise using continuous hyperoxic suppression of pRc drive, while stabilizing the drive from the central chemoreceptor by clamping end-tidal PCO2 (PETCO2) at the peak level attained during the hyperoxic period of a poikilocapnic ride. In the isocapnic protocol, the PETCO2 was maintained at a constant level by a negative feedback, open loop system. Five subjects completed four repetitions of each of the poikilocapnic and isocapnic protocols. In the poikilocapnic protocol, [Formula: see text] declined following the step into hyperoxia and then began to increase, whereas the decline in [Formula: see text] was maintained in the isocapnic protocol. However, the mean decrease in [Formula: see text] was not significantly different between the poikilocapnic (16.1 ± 5.0%) and isocapnic (14.9 ± 4.4%) protocols. These results suggest that the declining phase of [Formula: see text] is fully complete before the secondary central stimulating actions of hyperoxia on [Formula: see text] and that the pRc contributes about 15% of the drive to breathe in moderate intensity exercise. Key words: ventilatory control, carotid bodies, hyperoxia

scholarly journals Effect of Moderate-Intensity Exercise Training on Peak Oxygen Consumption in Patients With Hypertrophic Cardiomyopathy

JAMA ◽  
2017 ◽  
Vol 317 (13) ◽  
pp. 1349 ◽  
Author(s):  
Sara Saberi ◽  
Matthew Wheeler ◽  
Jennifer Bragg-Gresham ◽  
Whitney Hornsby ◽  
Prachi P. Agarwal ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Hypertrophic Cardiomyopathy ◽  
Exercise Training ◽  
Peak Oxygen Consumption ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise

Effects of sleep deprivation on thermoregulation during exercise

1984 ◽  
Vol 246 (1) ◽  
pp. R72-R77 ◽  
Author(s):  
M. N. Sawka ◽  
R. R. Gonzalez ◽  
K. B. Pandolf
Keyword(s):  
Sleep Deprivation ◽  
Sweat Rate ◽  
Thermal Conductance ◽  
Cycle Ergometer ◽  
Moderate Intensity ◽  
Control Test ◽  
Moderate Intensity Exercise ◽  
Ergometer Exercise ◽  
Total Body ◽  
And Control

Five fit men completed a practice, control, and sleep deprivation exercise test. Two nights of normal sleep preceded the control test, and 33 h of wakefulness preceded the sleep deprivation test. These tests consisted of 20 min of rest followed by 40 min of cycle-ergometer exercise (50% of peak O2 uptake, VO2) in a temperate (ambient temperature, 28 degrees C; relative humidity, 30%)-environment. Esophageal temperature (Tes), local sweat rate (mds), and chest thermal conductance (kch) were continuously measured. During exercise a 0.7 and 0.5 degrees C rise in Tes was found for the sleep deprivation and control tests, respectively. This increase in Tes values from rest to the end of exercise was greater (P = 0.08) for the sleep deprivation than control test. Total body sweat rate, calculated from Potter balance measurements, was 27% less (P less than 0.01) for the sleep deprivation than the control test. Both mds and kch values were lower (P less than 0.05) during the final 20 min of exercise for the sleep deprivation than control test. Final exercise mds values were 19% lower (P less than 0.05) for the sleep deprivation than control test. An asynchronous rather than a normal synchronous mds pattern was frequently observed during the sleep deprivation test. During the sleep deprivation test, the mds sensitivity (delta mds X delta Tes-1) was 38% lower (P less than 0.01) and kch sensitivity (delta kch X delta Tes-1) was 42% lower (P less than 0.05) than during the control test. These data indicate that sleep deprivation decreases evaporative and dry heat loss during moderate-intensity exercise.

Epinephrine infusion during moderate intensity exercise increases glucose production and uptake

2000 ◽  
Vol 278 (5) ◽  
pp. E949-E957 ◽  
Author(s):  
Stuart H. Kreisman ◽  
Nicholas Ah Mew ◽  
Mylène Arsenault ◽  
Sharon J. Nessim ◽  
Jeffrey B. Halter ◽  
...  
Keyword(s):  
Plasma Catecholamines ◽  
Glucose Production ◽  
Cycle Ergometer ◽  
Moderate Intensity ◽  
Metabolic Clearance ◽  
Moderate Exercise ◽  
Moderate Intensity Exercise ◽  
Epinephrine Infusion ◽  
Ergometer Exercise ◽  
Male Subjects

The glucoregulatory response to intense exercise [IE, >80% maximum O2 uptake (V˙o 2 max)] comprises a marked increment in glucose production (Ra) and a lesser increment in glucose uptake (Rd), resulting in hyperglycemia. The Ra correlates with plasma catecholamines but not with the glucagon-to-insulin (IRG/IRI) ratio. If epinephrine (Epi) infusion during moderate exercise were able to markedly stimulate Ra, this would support an important role for the catecholamines' response in IE. Seven fit male subjects (26 ± 2 yr, body mass index 23 ± 0.5 kg/m2,V˙o 2 max 65 ± 5 ml ⋅ kg− 1 ⋅ min− 1) underwent 40 min of postabsorptive cycle ergometer exercise (145 ± 14 W) once without [control (CON)] and once with Epi infusion [EPI (0.1 μg ⋅ kg− 1 ⋅ min− 1)] from 30 to 40 min. Epi levels reached 9.4 ± 0.8 nM (20× rest, 10× CON). Ra increased ∼70% to 3.75 ± 0.53 in CON but to 8.57 ± 0.58 mg ⋅ kg− 1 ⋅ min− 1in EPI ( P < 0.001). Increments in Ra and Epi correlated ( r 2 = 0.923, P ≤ 0.01). In EPI, peak Rd (5.55 ± 0.54 vs. 3.38 ± 0.46 mg ⋅ kg− 1 ⋅ min− 1, P = 0.006) and glucose metabolic clearance rate (MCR, P= 0.018) were higher. The Ra-to-Rdimbalance in EPI caused hyperglycemia (7.12 ± 0.22 vs. 5.59 ± 0.22 mM, P = 0.001) until minute 60 of recovery. A small and late IRG/IRI increase ( P = 0.015 vs. CON) could not account for the Ra increase. Norepinephrine (∼4× increase at peak) did not differ between EPI and CON. Thus Epi infusion during moderate exercise led to increments in Ra and Rd and caused rises of plasma glucose, lactate, and respiratory exchange ratio in fit individuals, supporting a regulatory role for Epi in IE. Epi's effects on Rd and MCR during exercise may differ from its effects at rest.

scholarly journals Modified Total-Body Recumbent Stepper Exercise Test for Assessing Peak Oxygen Consumption in People With Chronic Stroke

2008 ◽  
Vol 88 (10) ◽  
pp. 1188-1195 ◽  
Author(s):  
Sandra A Billinger ◽  
Benjamin Y Tseng ◽  
Patricia M Kluding
Keyword(s):  
Oxygen Consumption ◽  
Exercise Test ◽  
Health Care Professionals ◽  
Cycle Ergometer ◽  
Peak Oxygen Consumption ◽  
Exercise Protocol ◽  
Exercise Tests ◽  
Cycle Ergometer Exercise ◽  
Ergometer Exercise ◽  
Total Body

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.

Endurance training decreases plasma glucose turnover and oxidation during moderate-intensity exercise in men

1990 ◽  
Vol 68 (3) ◽  
pp. 990-996 ◽  
Author(s):  
A. R. Coggan ◽  
W. M. Kohrt ◽  
R. J. Spina ◽  
D. M. Bier ◽  
J. O. Holloszy
Keyword(s):  
Endurance Training ◽  
Plasma Glucose ◽  
Cycle Ergometer ◽  
Fat Free Mass ◽  
Strenuous Exercise ◽  
Moderate Intensity ◽  
Glucose Turnover ◽  
Moderate Intensity Exercise ◽  
Ergometer Exercise ◽  
Before And After

To assess the effects of endurance training on plasma glucose kinetics during moderate-intensity exercise in men, seven men were studied before and after 12 wk of strenuous exercise training (3 days/wk running, 3 days/wk cycling). After priming of the glucose and bicarbonate pools, [U-13C] glucose was infused continuously during 2 h of cycle ergometer exercise at 60% of pretraining peak O2 uptake (VO2) to determine glucose turnover and oxidation. Training increased cycle ergometer peak VO2 by 23% and decreased the respiratory exchange ratio during the final 30 min of exercise from 0.89 +/- 0.01 to 0.85 +/- 0.01 (SE) (P less than 0.001). Plasma glucose turnover during exercise decreased from 44.6 +/- 3.5 mumol.kg fat-free mass (FFM)-1.min-1 before training to 31.5 +/- 4.3 after training (P less than 0.001), whereas plasma glucose clearance (i.e., rate of disappearance/plasma glucose concentration) fell from 9.5 +/- 0.6 to 6.4 +/- 0.8 ml.kg FFM-1.min-1 (P less than 0.001). Oxidation of plasma-derived glucose, which accounted for approximately 90% of plasma glucose disappearance in both the untrained and trained states, decreased from 41.1 +/- 3.4 mumol.kg FFM-1.min-1 before training to 27.7 +/- 4.8 after training (P less than 0.001). This decrease could account for roughly one-half of the total reduction in the amount of carbohydrate utilized during the final 30 min of exercise in the trained compared with the untrained state.

Ten days of exercise training reduces glucose production and utilization during moderate-intensity exercise

1994 ◽  
Vol 266 (1) ◽  
pp. E136-E143 ◽  
Author(s):  
L. A. Mendenhall ◽  
S. C. Swanson ◽  
D. L. Habash ◽  
A. R. Coggan
Keyword(s):  
Endurance Training ◽  
Time Course ◽  
Plasma Concentrations ◽  
Glucose Production ◽  
Peak Oxygen Uptake ◽  
Cycle Ergometer ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Ergometer Exercise ◽  
Exercise Induced

We have previously shown that 12 wk of endurance training reduces the rate of glucose appearance (Ra) during submaximal exercise (Coggan, A. R., W. M. Kohrt, R. J. Spina, D. M. Bier, and J. O. Holloszy. J. Appl. Physiol. 68: 990-996, 1990). The purpose of the present study was to examine the time course of and relationship between training-induced alterations in glucose kinetics and endocrine responses during prolonged exercise. Accordingly, seven men were studied during 2 h of cycle ergometer exercise at approximately 60% of pretraining peak oxygen uptake on three occasions: before, after 10 days, and after 12 wk of endurance training. Ra was determined using a primed, continuous infusion of [6,6-2H]glucose. Ten days of training reduced mean Ra during exercise from 36.9 +/- 3.3 (SE) to 28.5 +/- 3.4 mumol.min-1.kg-1 (P < 0.001). Exercise-induced changes in insulin, C-peptide, glucagon, norepinephrine, and epinephrine were also significantly blunted. After 12 wk of training, Ra during exercise was further reduced to 21.5 +/- 3.1 mumol.min-1.kg-1 (P < 0.001 vs. 10 days), but hormone concentrations were not significantly different from 10-day values. The lower glucose Ra during exercise after short-term (10 days) training is accompanied by, and may be due to, altered plasma concentrations of the major glucoregulatory hormones. However, other adaptations must be responsible for the further reduction in Ra with more prolonged training.

Cholinergic and opioid involvement in release of growth hormone during exercise and recovery

1993 ◽  
Vol 75 (2) ◽  
pp. 870-878 ◽  
Author(s):  
D. L. Thompson ◽  
J. Y. Weltman ◽  
A. D. Rogol ◽  
D. L. Metzger ◽  
J. D. Veldhuis ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Oxygen Consumption ◽  
Blood Lactate ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Exercise Bout ◽  
Peak Oxygen Consumption ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Testing Period

Cholinergic and opioid pathways have been implicated as mediators of the increased growth hormone (GH) release observed during exercise. This study compared the GH responses induced by a moderate-intensity exercise bout during treatment with placebo (Plac), the opioid receptor antagonist naltrexone (Nalt), the indirect cholinergic agonist pyridostigmine (PD), or a combination of the two drugs (P + N). Ten active males served as subjects (age, 25.1 +/- 0.6 yr; wt, 79.7 +/- 2.5 kg; % body fat, 14.9 +/- 1.4; peak oxygen consumption, 46.2 +/- 2.7 ml.kg-1 x min-1). Blood samples were drawn at 5-min intervals during the 4.5-h testing period to determine the GH concentration. The testing period was divided as follows: 0600–700 h = baseline, 0700–0800 h = preexercise, 0800–0830 h = exercise, and 0830–1030 h = recovery. Drugs were administered 1 h before exercise (at 0700 h). Exercise consisted of 30 min of cycling at an individualized work load previously found to elicit a blood lactate concentration of 2.5 mM. Heart rate, oxygen consumption, blood lactate, and blood glucose were measured throughout the exercise period. Results indicated that neither the resting GH concentration nor the metabolic parameters during exercise were altered by the treatments. Peak serum GH concentration was not significantly altered by the treatments (range 7.3 +/- 2.0 to 12.6 +/- 4.4 micrograms/l).(ABSTRACT TRUNCATED AT 250 WORDS)

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

2009 ◽  
Vol 34 (4) ◽  
pp. 603-608 ◽  
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.

Sign in / Sign up

Export Citation Format

Share Document