EXERCISE IN THE TERRESTRIAL CHRISTMAS ISLAND RED CRAB GECARCOIDEA NATALIS - ENERGETICS OF LOCOMOTION

The respiratory and circulatory physiology of exercising Christmas Island red crabs Gecarcoidea natalis were investigated with respect to their annual breeding migration. Red crabs were allowed to walk for up to 45 min. During this exercise period, the functioning of the circulatory system in gas transport and the energy status of the red crabs were quantified. Energy production during exercise required both aerobic and anaerobic contributions. The aerobic scope of G. natalis was low, with only a doubling of the resting rate of oxygen consumption (resting M(dot)O2=95±15 µmol kg-1 min-1). Maximal O2 consumption was attained within the first 5 min of exercise and the level remained stable thereafter. The anaerobic contribution to energy production was directly related to the speed of locomotion. l-lactate levels in blood and leg muscle were similar throughout the exercise period; blood lactate concentration was 33.39±2.29 mmol l-1 after 45 min of exercise. Heart rate in resting animals was 56±7 beats min-1. At the onset of exercise, heart rate also doubled, but without a significant increase in cardiac output. Increased O2 delivery was facilitated by increased extraction from the blood. During the 45 min of exercise, glucose levels increased rapidly in the muscle tissue (from 2.30±0.54 to 8.78±1.20 mmol l-1) and subsequently in the blood (from 1.22±0.26 to 2.12±0.17 mmol l-1), fuelling increased glycolysis during locomotion. The energy production from stored glucose/glycogen was sufficient to support the energetic needs of locomotion, since the energy charge remained stable at 0.82. Haemolymph l-lactate levels in crabs sampled in the field after migration were high compared with levels in many crustacean species but equivalent to l-lactate levels in laboratory animals exercised for less than 10 min. During their migration, therefore, the red crabs avoid exceptional l-lactate build-up in the blood by either walking very slowly or intermittently. However, G. natalis are exceptionally well adapted to cope with exhaustive locomotion and the resultant severe metabolic acidosis.

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EXERCISE IN THE TERRESTRIAL CHRISTMAS ISLAND RED CRAB GECARCOIDEA NATALIS - BLOOD GAS TRANSPORT

Journal of Experimental Biology ◽

10.1242/jeb.188.1.235 ◽

1994 ◽

Vol 188 (1) ◽

pp. 235-256 ◽

Cited By ~ 1

Author(s):

A Adamczewska ◽

S Morris

Keyword(s):

Gas Transport ◽

Lactate Production ◽

Circulatory System ◽

Indirect Evidence ◽

Blood Gas ◽

Christmas Island ◽

Exercise Period ◽

Gas Measurements ◽

Gecarcoidea Natalis ◽

O2 Delivery

The respiratory and circulatory physiology of the terrestrial Christmas Island red crab Gecarcoidea natalis was investigated with respect to exercise in the context of its annual breeding migration. Red crabs were allowed to walk for predetermined periods of up to 45 min. During this exercise period, blood gas measurements were made on venous, pulmonary and arterial samples to assess the function of the lungs in gas exchange and the performance of the circulatory system in gas transport and to determine the role and importance of the haemocyanin. The lungs of G. natalis were very efficient at O2 uptake, pulmonary blood being 8090 % saturated throughout the 45 min exercise period. The maximum O2-carrying capacity was 1.1 mmol l-1, and haemocyanin (Hc) delivered 86 % of oxygen in resting crabs and 97 % during exercise. Oxygen delivery to the tissues was diffusion-limited during exercise. Indirect evidence, from the changes in haemolymph pH during transit through the lungs, suggested that the lung is the site of CO2 excretion. The Bohr shift was high at high pH (pH 7.87.5, phi=-1.23) but decreased at low pH (pH 7.16.8, phi=-0.48). The decreased Hc affinity for O2 during the exercise period facilitated O2 delivery to the tissues without impairing O2 loading at the lungs. The decrease in pH was sufficient to explain the change of affinity of Hc for O2 during the exercise period. The marked acidosis (0.8 pH unit decrease) was largely metabolic in origin, especially during sustained locomotion, but less than could be predicted from concomitant lactate production.

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Using Submaximal Exercise Heart Rate for Monitoring Cardiorespiratory Fitness Changes in Professional Soccer Players: A Replication Study

International Journal of Sports Physiology and Performance ◽

10.1123/ijspp.2020-0554 ◽

2020 ◽

pp. 1-7

Author(s):

Stefan Altmann ◽

Rainer Neumann ◽

Sascha Härtel ◽

Alexander Woll ◽

Martin Buchheit

Keyword(s):

Heart Rate ◽

Potential Role ◽

Lactate Concentration ◽

Soccer Players ◽

Exercise Heart Rate ◽

Incremental Test ◽

Professional Soccer ◽

Optimal Thresholds ◽

The Moment

Purpose: To assess the value of monitoring changes in fitness in professional soccer players, using changes in heart rate at submaximal intensity (HR12km/h) over the velocity at a lactate concentration of 4 mmol/L (v4mmol/L). The authors reexamined (1) a range of threshold magnitudes, which may improve detecting substantial individual changes and (2) the agreement between changes in these 2 variables. Methods: On at least 2 occasions during different moments of the season, 97 professional soccer players from Germany (first, second, and fourth division) completed an incremental test to determine HR12km/h and v4mmol/L. Optimal thresholds for changes in HR12km/h and v4mmol/L were assessed, using various methods (eg, smallest worthwhile change + typical error [TE], successive reiterations approach). Agreement between both variable changes was examined for the whole sample (225 comparisons), 4 different subgroups (depending on the moment of the season), and in an individual over 6 years (n = 23 tests). Results: Changes of 4.5% and 6.0% for HR12km/h and v4mmol/L, respectively, were rated as optimal to indicate substantial changes in fitness. Depending on the (sub)groups analyzed, these thresholds yielded 0% to 2% full mismatches, 22% to 38% partial agreements, and 60% to 78% full agreements in terms of fitness change interpretation between both variables. Conclusions: When lactate sampling during incremental tests is not possible, practitioners willing to monitor adult professional soccer players’ (Germany; first, second, and fourth division) training status can confidently implement short, 3-minute submaximal runs, with 4.5% changes in HR12km/h being indicative of true substantial fitness changes, with 60% to 78% accuracy. Future studies should investigate the potential role of confounding factors of HR12km/h to improve changes in fitness prediction.

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Comparison of rating of perceived exertion scales during incremental and interval exercise

Kinesiology ◽

10.26582/k.51.2.1 ◽

2019 ◽

Vol 51 (2) ◽

pp. 150-157 ◽

Cited By ~ 4

Author(s):

Blaine E. Arney ◽

Jos J. de Koning ◽

Carl Foster ◽

John P. Porcari ◽

Richard P. Mikat ◽

...

Keyword(s):

Heart Rate ◽

Perceived Exertion ◽

Random Sequence ◽

Lactate Concentration ◽

Rating Of Perceived Exertion ◽

Peak Power Output ◽

Exercise Heart Rate ◽

Heart Rate Reserve ◽

Physiological Measures ◽

Interval Exercise

The Rating of Perceived Exertion (RPE) is an important measure of exercise intensity, which is useful both as a primary and adjunctive method of exercise prescription. However, there are multiple variants of the Borg RPE scale, primarily the Borg 6-20 RPE scale (BORG-RPE) and the Borg Category-Ratio-10 scale (BORG-CR10). There are inadequate data available to address the comparability and interchangeability of these two widely used scales. Well-trained non-athletes performed two increment cycle tests, with each scale used in a random sequence. Subjects also performed interval sessions at three intensities (50, 75 and 85% of peak power output) with each scale used in a random sequence. There were very large correlations during the incremental exercise between the conventional physiological measures (% heart rate reserve – r=0.89 & r=.87); and %VO2reserve (r=.88 & r=.90) and RPE measured by either the BORG-RPE or the BORGCR10, respectively. This pattern was also evident during the interval exercise (% heart rate reserve (r=.85 & r=.84; and blood lactate concentration – r=.74 & r=.78) and RPE measured by either the BORG-RPE or the BORG-CR10, respectively. The relationship between RPE measured by the BORG-RPE and the BORGCR10 was large and best described by a non-linear relationship for both the incremental (R2=89) and the interval (R2=.89) exercise. The incremental and interval curves were virtually overlapping. We concluded that the two most popular versions of the RPE scale, BORG-RPE and BORG-CR10, were both highly related to the conventional physiological measures and very strongly related to each other, with an easily described conversion.

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Effect of Thiamine Pyrophosphate on Levels of Serum Lactate, Maximum Oxygen Consumption and Heart Rate in Athletes Performing Aerobic Activity

Journal of International Medical Research ◽

10.1177/147323000803600608 ◽

2008 ◽

Vol 36 (6) ◽

pp. 1220-1226 ◽

Cited By ~ 2

Author(s):

VM Bautista-Hernández ◽

R López-Ascencio ◽

M Del Toro-Equihua ◽

C Vásquez

Keyword(s):

Heart Rate ◽

Oxygen Consumption ◽

Serum Lactate ◽

Thiamine Pyrophosphate ◽

Exercise Heart Rate ◽

Maximum Oxygen Consumption ◽

Double Blind ◽

Male Athletes ◽

Aerobic Activity ◽

Lactate Levels

The aim of this study was to determine the effect of thiamine pyrophosphate (TPP) on serum lactate levels, maximum oxygen consumption (Vo2max) and heart rate in male athletes performing aerobic activity. A double-blind, randomized, crossover study was performed in which lactate levels, Vo2max and heart rates in 27 male athletes were compared at rest and after exercise, following administration of placebo (sodium chloride 0.9%) or TPP (1 mg/kg). At rest, serum lactate levels after placebo or TPP were similar; however, after exercise, the levels were lower in the athletes after taking TPP than after placebo. During exercise, Vo2max in athletes on TPP was higher than on placebo. At rest, heart rate after taking placebo or TPP was similar but, after exercise, heart rate was lower after taking TPP than after placebo. It is concluded that TPP caused serum lactate levels and heart rate to be lower than placebo and Vo2max to be higher in athletes performing aerobic physical activity.

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Sympathetic outflow to the skeletal muscle in humans increases during prolonged light exercise

Journal of Applied Physiology ◽

10.1152/jappl.1997.82.4.1237 ◽

1997 ◽

Vol 82 (4) ◽

pp. 1237-1243 ◽

Cited By ~ 34

Author(s):

Mitsuru Saito ◽

Ryoko Sone ◽

Masao Ikeda ◽

Tadaaki Mano

Keyword(s):

Skeletal Muscle ◽

Heart Rate ◽

Blood Lactate ◽

Muscle Sympathetic Nerve Activity ◽

Initial Period ◽

Lactate Concentration ◽

Blood Lactate Concentration ◽

Tympanic Temperature ◽

Exercise Heart Rate ◽

Dependent Manner

Saito, Mitsuru, Ryoko Sone, Masao Ikeda, and Tadaaki Mano.Sympathetic outflow to the skeletal muscle in humans increases during prolonged light exercise. J. Appl. Physiol. 82(4): 1237 – 1243, 1997.—To investigate the effects of exercise duration on muscle sympathetic nerve activity (MSNA), heart rate, blood pressure (BP), tympanic temperature, blood lactate concentration, and thigh electromyogram were measured in eight volunteers during 30 min of cycling in the sitting position at an intensity of 40% of maximal oxygen uptake. MSNA burst frequency increased 18 min after exercise was begun (25 ± 4 bursts/min at baseline and 36 ± 5 bursts/min at 21 min of exercise), reaching 41 ± 5 bursts/min at the end of exercise. Heart rate and systolic BP increased during exercise. Twenty minutes after commencement of exercise, however, both systolic and diastolic BP values tended to drop compared with the initial period of exercise. Tympanic temperature increased in a time-dependent manner, and the increment was significant 12 min after exercise was begun. Blood lactate concentration and integrated electromyogram showed no significant changes during exercise. The increased MSNA during prolonged light-intensity exercise may be a secondary effect of the drop in BP as a result of blood redistribution caused by thermoregulation rather than by metaboreflex.

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The functioning of the haemocyanin of the terrestrial christmas island red crab gecarcoidea natalis and roles for organic modulators

Journal of Experimental Biology ◽

10.1242/jeb.201.23.3233 ◽

1998 ◽

Vol 201 (23) ◽

pp. 3233-3244 ◽

Cited By ~ 2

Author(s):

A. M. Adamczewska ◽

S. Morris

Keyword(s):

Lactate Concentration ◽

Specific Effect ◽

Time Dependent ◽

Binding Properties ◽

Christmas Island ◽

Land Crabs ◽

Gecarcoidea Natalis ◽

O2 Binding

Gecarcoidea natalis is a land crab that migrates annually several kilometres to breed. The O2-binding properties of haemocyanin in G. natalis were investigated in vitro to test the idea that the O2-binding properties of the haemocyanin of land crabs are not dependent on circulating modulators and to provide a model of haemocyanin functioning during exercise. The affinity of the haemocyanin for O2 decreased with increasing temperature (change in the heat of oxygenation; capdelta H=-59 kJ mol-1). The haemocyanin of G. natalis apparently differs from that of other terrestrial crabs in showing haemocyanin O2 modulation by both organic and inorganic molecules. Haemocyanin O2-affinity was not affected by Mg2+ but was sensitive to changes in Ca2+ concentration ( capdelta logP50/ capdelta log[Ca]=-0.61, where P50 is the partial pressure of O2 required for half-maximal O2 binding). The Bohr factor was modest ( &phgr;=-0.26+/-0.03, N=4, in whole haemolymph at 25 degreesC) and there was no specific effect of CO2 on the O2-binding properties of the haemocyanin. An increase in urate concentration increased haemocyanin O2-affinity, but the effect was linear ( capdelta logP50/ capdelta [urate]=-0.06) and not logarithmic as is the case in other species. The effect of l-lactate on the haemocyanin O2-affinity in G. natalis was unique among the crustaceans,because an increase in l-lactate concentration decreased the haemocyanin O2-affinity. The effect of l-lactate on haemocyanin O2-affinity ( capdelta logP50/ capdelta log[lactate]) was time-dependent and decreased from a maximum of 0.044 on day 1 to 0.001 after 4 days of storage at 4 degreesC. The presence of an unknown dialysable and unstable factor in the haemolymph is postulated to explain the time-dependent effect of l-lactate on haemocyanin O2-binding properties. Model oxygen equilibrium curves constructed for in vivo conditions showed that the reverse effect of l-lactate was advantageous by decreasing the O2-affinity of the haemocyanin beyond that predicted by the Bohr shift alone and assisted in O2 off-loading at the tissues. This effect of lactate can only provide an advantage if the gas-exchange organs maintain arterial O2 loading and thus is dependent on lung function in land crabs and must have occurred coincident with the evolution of these other features.

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The Short Term Cardiovascular and Pulmonary Responses to Exercise in Young Adults

Journal of Shalamar Medical & Dental College - JSHMDC ◽

10.53685/jshmdc.v1i1.46 ◽

2019 ◽

Vol 1 (1) ◽

pp. 13-18

Author(s):

Ambreen Khalid ◽

Adeela Shahid ◽

Farhat Aitazaz

Keyword(s):

Physical Activity ◽

Heart Rate ◽

Diastolic Pressure ◽

Cross Sectional Study ◽

Exercise Heart Rate ◽

P Value ◽

Respiratory Response ◽

Cross Sectional ◽

Post Exercise ◽

Exercise Period

Background: Impaired cardiovascular and respiratory functions are associated with increased mortality andmorbidity. Exploration of the relation between physical activity and cardiovascular and respiratory functions canhelp in understanding the mechanisms of how physical activity improves a person’s quality of life. Objectives: To investigate the post exercise cardio-respiratory response of normal healthy adults and to determine ifthere are gender differences in the post exercise cardio-respiratory response. Methods: A cross-sectional study was conducted on 1st and 2nd year MBBS students of Shalamar Medical andDental College in the department of Physiology. Measurement of Pulmonary functions and recording of ECG wasdone by using Power LAB before and after exercise. Statistical analysis was done on SPSS version 21, student t-testwas applied and p- value < 0.05 was considered statistically significant. Results: The respiratory rate, respiratory minute volume and tidal volume increased while oxygen saturationdecreased significantly after exercise. Heart rate increased significantly in post exercise period. The pre exercisesystolic and diastolic blood pressure increased significantly after exercise. There was a significant post exerciseincrement in diastolic pressure in males than in females. QT was significantly decreased in post-exercise period infemale subjects. Conclusion: The respiratory parameters changed significantly after exercise. Heart rate and blood pressureincreased significantly both in male and female subjects. QT interval decreased significantly only in females;however, changes in PR interval and QRS complex were not significant.

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