Respiratory Responses to Simultaneous Static and Rhythmic Exercises in Humans

1975 ◽  
Vol 49 (5) ◽  
pp. 427-432 ◽  
Author(s):  
R. L. Wiley ◽  
A. R. Lind
Keyword(s):  
Oxygen Consumption ◽  
Minute Ventilation ◽  
Work Load ◽  
Bicycle Ergometer ◽  
Hand Grip ◽  
Static Effort ◽  
The Mean ◽  
Rhythmic Exercise ◽  
Male Subjects ◽  
Respiratory Responses

1. Six male subjects performed simultaneous static (hand-grip) and rhythmic (bicycle ergometer) exercises while their respiratory responses were measured. 2. Oxygen consumption increased with the intensity of rhythmic work load, with a modest additional oxygen consumption accompanying the addition of static effort during the rhythmic exercise. 3. Minute ventilation (V̇E) increased directly with rhythmic exercise, but increased disproportionately to the metabolic need when static effort was added. The mean increment of V̇E elicited by the static exercise influence was nearly constant at 20 1/min, regardless of the rhythmic load present. 4. Possible reflex mechanisms which result in disruption of the normally well-matched ventilation and metabolic oxygen demands whenever static effort is present are discussed.

Fibrinolytic and hemostatic changes during and after maximal exercise in males

1976 ◽  
Vol 40 (3) ◽  
pp. 287-292 ◽  
Author(s):  
G. L. Davis ◽  
C. F. Abildgaard ◽  
E. M. Bernauer ◽  
M. Britton
Keyword(s):  
Heart Rate ◽  
Factor Viii ◽  
Fibrinolytic Activity ◽  
Work Load ◽  
Bicycle Ergometer ◽  
Maximal Heart Rate ◽  
Relative Level ◽  
Maximum Exercise ◽  
Activity Factor ◽  
Male Subjects

To evaluate changes in fibrinolytic activity, factor VIII and other hematological variables during and after a progressive step increment in work load, 10 healthy male subjects (22–27 yr of age) were exercised to exhaustion on an electromagnetic bicycle ergometer. Blood samples were drawn serially throughout the experiment. Little change in fibrinolytic activity was observed before 70–80% maximum heart rate (MHR) was achieved. Major changes occurred after 80% MHR. Peak values coincided with maximum exercise. In contrast major changes in factor VIII were observed between 95 and 100% MHR with peak values occurring 5–10 min postexercise. An increase in white blood cell count, platelet count, and retention was observed at maximum exercise. One individual failed to demonstrate an increase in either fibrinolytic or factor VIII activity. Relating the data to either the percent maximal oxygen uptake or percent maximal heart rate demonstrates the importance of the exercise protocol and exerting all subjects to the same relative level of physiological work.

Effects of glycogen depletion and work load on postexercise O2 consumption and blood lactate

1979 ◽  
Vol 47 (3) ◽  
pp. 514-521 ◽  
Author(s):  
S. S. Segal ◽  
G. A. Brooks
Keyword(s):  
Blood Lactate ◽  
Slow Component ◽  
Minute Ventilation ◽  
Co2 Flux ◽  
Work Load ◽  
Bicycle Ergometer ◽  
Co2 Production ◽  
O2 Consumption ◽  
Glycogen Depletion ◽  
Heavy Exercise

To study a possible relationship between blood lactate and O2 consumption (VO2) after exercise, 11 male subjects exercised on a bicycle ergometer at moderate and heavy work loads in both normal glycogen and glycogen-depleted states. At rest, glycogen depletion resulted in significantly lowered blood glucose and lactate concentrations, CO2 production (VCO2), respiratory exchange ratio (R), and minute ventilation (VE). With the exception of glucose, these variables changed more in response to heavy exercise (HE: 2 min at a mean of 1,750 kg.m/min) than to moderate exercise (ME: 2 min at a mean of 1,000 kg.m/min). At either work load, VCO2, R, and lactate showed consistently greater responses in the normal glycogen state. The slope of the initial component of the postexercise VO2 curve was unaffected by either work load or lactate. Although the slope of the slow component of the postexercise VO2 curve became significantly more negative after HE, it was unaffected by the level of lactate. These results are inconsistent with the hypothesis of a “lactacid O2 debt.” Exercise intensity was the predominant factor influencing the magnitude and kinetics of postexercise VO2. Glycogen depletion resulted in lower VCO2, R, and blood lactate, but higher VE during heavy exercise. The results suggest that factors, in addition to CO2 flux to the lungs, influence VE during exercise.

Maximal heart rate during work in older men

1959 ◽  
Vol 14 (4) ◽  
pp. 562-566 ◽  
Author(s):  
Irma Åstrand ◽  
Per-Olof Åstrand ◽  
Kaare Rodahl
Keyword(s):  
Heart Rate ◽  
Ambient Air ◽  
Work Load ◽  
Work Capacity ◽  
Bicycle Ergometer ◽  
Maximal Heart Rate ◽  
Average Maximum ◽  
Work Up ◽  
Aerobic Work Capacity ◽  
Male Subjects

Nine 56–68-year-old male subjects performed muscular work up to maximal loads on a bicycle ergometer while breathing both ambient air and oxygen. Heart rate increased to an average maximum of 163/min. The maximal O2 intake averaged 2.24 l/min. and the blood lactic acid concentration 85 mg/100 ml. In no case was the maximal heart rate higher when breathing O2 than when breathing air. This low maximal heart rate in older people probably limits the capacity for O2 intake. Four subjects were able to work for about 1 hour without any sign of exhaustion on a work load requiring an O2 consumption of about 50% of their maximal aerobic work capacity. Submitted on October 3, 1958

Effect of ENDUROX™ on Metabolic Responses to Submaximal Exercise

1999 ◽  
Vol 9 (4) ◽  
pp. 434-442 ◽  
Author(s):  
Samuel N. Cheuvront ◽  
Robert J. Moffatt ◽  
Kyle D. Biggerstaff ◽  
Shawn Bearden ◽  
Paul McDonough
Keyword(s):  
Oxygen Consumption ◽  
Repeated Measures ◽  
Perceived Exertion ◽  
Minute Ventilation ◽  
Rating Of Perceived Exertion ◽  
Peak Oxygen Consumption ◽  
Metabolic Responses ◽  
Double Blind ◽  
Serum Glycerol ◽  
Male Subjects

Claims that ENDUROX™ enhances performance by altering metabolic responses to exercise were tested. In a double-blind crossover design, 10 male subjects were randomly assigned to consume 400 mg of placebo or 800 mg ENDUROX™ for 7 days. Cycle ergometry was performed for 30 minutes at 25%, followed by 10 min at 65% of peak oxygen consumption. After a 1-week washout period, subjects performed the identical exercise protocol following 7 days of reciprocal supplemental conditions. Expired gases were collected and analyzed continuously for oxygen consumption, minute ventilation, and respiratory exchange ratio. Heart rate, blood pressure, rating of perceived exertion, blood lactate, and serum glycerol data were also collected at regular intervals. A two-way ANOVA with repeated measures revealed no significant main or interaction effects involving group differences (p > 0.05) between trials for any variable during rest, 25% or 65% (VO2 peak), or recovery. Our findings do not support the ergogenic claims for ENDUROX™.

Metabolic, cardiovascular, and respiratory factors in the development of fatigue in lifting tasks

1978 ◽  
Vol 45 (1) ◽  
pp. 64-68 ◽  
Author(s):  
J. S. Petrofsky ◽  
A. R. Lind
Keyword(s):  
Oxygen Uptake ◽  
Maximal Oxygen Uptake ◽  
Work Load ◽  
Specific Weight ◽  
Bicycle Ergometer ◽  
Isometric Contractions ◽  
Bicycle Ergometry ◽  
Physiological Capacity ◽  
Male Subjects ◽  
Extended Work

Three well-trained male subjects served as volunteers in these experiments to examine the physiological capacity for extended work during lifting tasks. The maximal oxygen uptake (VO2max) during lifting was always lower than work on the bicycle ergometer. However, the work load during lifting which could be maintained for 1--4 h was 50% of the VO2max for lifting each specific weight of box; the limit for lifting light boxes without fatigue was at an oxygen uptake of about 25% of the VO2max obtained from bicycle ergometry. Significant fatigue in the forearm muscles was found during prolonged lifting as assessed from the endurance of isometric contractions and from the surface electromyogram (EMG), and was more pronounced as the weight of the box increased.

BICYCLE ERGOMETER MEASUREMENT OF MAXIMAL OXYGEN UPTAKE IN CHILDREN

1967 ◽  
Vol 45 (6) ◽  
pp. 937-946 ◽  
Author(s):  
Gordon R. Cumming ◽  
Werner Friesen
Keyword(s):  
Oxygen Uptake ◽  
Pulse Rate ◽  
Maximal Oxygen Uptake ◽  
Work Load ◽  
Bicycle Ergometer ◽  
Cycle Ergometer ◽  
Uptake Curve ◽  
Exercise Tests ◽  
Straight Line ◽  
The Mean

Seven to 15 maximal exercise tests on a cycle ergometer were done on twenty boys, 11 to 15 years of age, until the work load was sufficiently high that it could not be sustained for 3 min. The mean maximal pulse rate was 202 beats/min, and the mean maximal oxygen uptake was 53.8 ml/kg per min. A plateau of the oxygen uptake curve occurred in only 7 of the 20 subjects, whereas the pulse rate reached a plateau in 13 subjects. On the basis of the pulse rate – work load straight line relationship for submaximal exercise, the intensity of the load that the subjects were able to complete was such that a mean predicted pulse rate of 247 beats/min would have resulted. This information can be utilized to obtain maximal oxygen uptake from a single test in children.

Bicycle Crank Length

1976 ◽  
Vol 20 (18) ◽  
pp. 415-421
Author(s):  
V. John Gross ◽  
Corwin A. Bennett
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Perceived Exertion ◽  
Young Male ◽  
Bicycle Ergometer ◽  
Adult Males ◽  
Heavy Load ◽  
Percentage Points ◽  
Male Subjects ◽  
Crank Length

An experiment was conducted varying bicycle crank length as a ratio of cyclist's crotch height over a range from 0.17 to 0.23. A light and a heavy load were used with ten young male subjects. Heart rate, oxygen consumption and perceived exertion measures were taken during bicycle ergometer pedaling sessions. All measures showed the superiority of a crank length of about 0.20 of crotch height (0.10 of standing height). A change of crank length of three percentage points of crotch height increases energy expenditure by one kcal/minute. The standard crank is too long for 60% of adult males and almost 100% of females. Varied crank lengths or adjustable cranks should be made available.

Iron-Deficiency Anaemia: Its Effect on Maximum Aerobic Power and Responses to Exercise in African Males Aged 17–40 Years

1973 ◽  
Vol 44 (6) ◽  
pp. 555-562 ◽  
Author(s):  
C. T. M. Davies ◽  
A. C. Chukweumeka ◽  
J. P. M. Van Haaren
Keyword(s):  
Cardiac Output ◽  
Plasma Volume ◽  
Aerobic Power ◽  
Minute Ventilation ◽  
Haemoglobin Concentration ◽  
Work Load ◽  
Severe Anaemia ◽  
Bicycle Ergometer ◽  
Oxygen Intake ◽  
Maximum Aerobic Power

1. The physiological responses to exercise of two groups of industrial workers with moderate and severe anaemia were measured and compared with a group of matched controls, working and living under similar conditions. Exercise was performed on a stationary bicycle ergometer at five consecutive work loads. During the final minute of each exercise periods, oxygen intake, minute ventilation volume, and cardiac and respiratory frequencies were measured. On a separate occasion, blood haemoglobin concentration was measured at rest and cardiac output and blood and plasma volumes were estimated while subjects exercised at a fixed percentage of the maximum aerobic power for 6 min. 2. Oxygen intake for a given work load and ventilation rate was similar in all subjects studied but exercise cardiac output was elevated in the anaemic group. The increased cardiac output was due to an increased heart rate, the stroke volume being similar in the anaemic and control subjects. There was a marked decrement (∼34%) in maximum aerobic power and some evidence of a raised plasma volume in the severely anaemic group. 3. These results suggest that anaemia impairs performance during moderate and near maximum exercise. There is an associated rise of cardiac output and plasma volume.

Human Skeletal Muscle Phosphorylase Activities with Exercise and Training

1972 ◽  
Vol 50 (11) ◽  
pp. 1038-1042 ◽  
Author(s):  
A. W. Taylor ◽  
M. A. Booth ◽  
S. Rao
Keyword(s):  
Skeletal Muscle ◽  
Work Load ◽  
Bicycle Ergometer ◽  
Healthy Male ◽  
Maximal Aerobic Capacity ◽  
Work Time ◽  
Muscle Phosphorylase ◽  
Male Subjects ◽  
Exercise And Training ◽  
And Training

Fifteen healthy male subjects classified as sedentary (7) or active (8), exercised to exhaustion on a bicycle ergometer at a work load requiring 70% of their maximal aerobic capacity. Biopsy samples of the vastus lateral is muscle were taken at rest, at the time of fatigue, and after a 10 min recovery. Training increased [Formula: see text], [Formula: see text], work time to fatigue, skeletal muscle glycogen levels, and phosphorylase a activity (P < 0.01). An exhaustive submaximal exercise reduced the glycogen levels of the trained group to values similar to the fatigue levels of the nontrained subjects: the higher the initial glycogen levels, the longer the subjects were able to exercise before the onset of fatigue. Skeletal muscle phosphorylase a activities decreased with exercise to fatigue in all groups whereas phosphorylase b activities were maintained. Training had no effect on resting phosphorylase b activity.

scholarly journals Exercise Modulation of Blood Pressure, Respiratory Rate and Pulse Rate in Undergraduate Students

2021 ◽  
Author(s):  
Taiwo E. O. ◽  
Thanni L. O. A.
Keyword(s):  
Blood Pressure ◽  
Respiratory Rate ◽  
Undergraduate Students ◽  
Pulse Rate ◽  
Circulatory System ◽  
Bicycle Ergometer ◽  
Postgraduate Students ◽  
Stop Watch ◽  
The Mean ◽  
Male Subjects

Background: Physical Activity improves the functional capacity of the circulatory system with minimum myocardium stress. Objectives: This study was designed to assess exercise modulation and sex difference of blood pressure (BP), respiratory rate (RR) and pulse rate (PR) of selected undergraduate students. Design: This study involved 360 students selected using convenience sampling method, aged between 18 and 35 years. Lecturers and postgraduate students were exempted from the study. BP was measured using Sphygmomanometer before exercise and 30 minutes interval during exercise for two hours. Bicycle Ergometer was used as the exercise apparatus. Stop watch was used to measure PR and RR. Data were analyzed using descriptive statistics. Results: In total, 360 subjects, 180 males and 180 females, were included in the study. The mean SBP at baseline was 111.59 mmHg±0.35. It reduced to 96.99 mmHg±0.36 after 120 minutes of exercise (p=0.000). The mean DBP at baseline was 69.78mmHg±0.32. It reduced to 56.01mmHg±0.30 after 120 minutes of exercise (p=0.000). The mean Respiratory Rate (RR) at baseline was 15.91 cycles/ minute±0.11. It increased to 28.82 cycles/minute±0.21 after 120 minutes of exercise (p=0.000). The mean Rate Pulse Pressure (RPP) at baseline was 8322.35 mmHg. cycles/ minute±0.05 It increased to 12033.55mmHg.cycles/minute±0.21 after 120 minutes of exercise (p=0.000). Moreover, the male-female relationships showed that the SBP, DBP, RR and RPP were significantly lower in female than male subjects (p=0.000). Conclusions: Exercise reduces SBP and DBP. This reduction is greater among females.

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