Control of ventilation in elite synchronized swimmers

1987 ◽  
Vol 63 (3) ◽  
pp. 1019-1024 ◽  
Author(s):  
R. L. Bjurstrom ◽  
R. B. Schoene
Keyword(s):  
Heart Rate ◽  
Ventilatory Response ◽  
Minute Ventilation ◽  
Mean Value ◽  
Heart Rate Change ◽  
Breath Holding ◽  
Breath Hold ◽  
Lung Volumes ◽  
Co2 Partial Pressure ◽  
Control Of Ventilation

Synchronized swimmers perform strenuous underwater exercise during prolonged breath holds. To investigate the role of the control of ventilation and lung volumes in these athletes, we studied the 10 members of the National Synchronized Swim Team including an olympic gold medalist and 10 age-matched controls. We evaluated static pulmonary function, hypoxic and hypercapnic ventilatory drives, and normoxic and hyperoxic breath holding. Synchronized swimmers had an increased total lung capacity and vital capacity compared with controls (P less than 0.005). The hypoxic ventilatory response (expressed as the hyperbolic shape parameter A) was lower in the synchronized swimmers than controls with a mean value of 29.2 +/- 2.6 (SE) and 65.6 +/- 7.1, respectively (P less than 0.001). The hypercapnic ventilatory response [expressed as S, minute ventilation (1/min)/alveolar CO2 partial pressure (Torr)] was no different between synchronized swimmers and controls. Breath-hold duration during normoxia was greater in the synchronized swimmers, with a mean value of 108.6 +/- 4.8 (SE) vs. 68.03 +/- 8.1 s in the controls (P less than 0.001). No difference was seen in hyperoxic breath-hold times between groups. During breath holding synchronized swimmers demonstrated marked apneic bradycardia expressed as either absolute or heart rate change from basal heart rate as opposed to the controls, in whom heart rate increased during breath holds. Therefore the results show that elite synchronized swimmers have increased lung volumes, blunted hypoxic ventilatory responses, and a marked apneic bradycardia that may provide physiological characteristics that offer a competitive advantage for championship performance.(ABSTRACT TRUNCATED AT 250 WORDS)

Sexual influence on the control of breathing

1983 ◽  
Vol 54 (4) ◽  
pp. 874-879 ◽  
Author(s):  
D. P. White ◽  
N. J. Douglas ◽  
C. K. Pickett ◽  
J. V. Weil ◽  
C. W. Zwillich
Keyword(s):  
Ventilatory Response ◽  
Minute Ventilation ◽  
Premenopausal Women ◽  
Co2 Production ◽  
Menstrual Phase ◽  
Co2 Partial Pressure ◽  
Ventilatory Responses ◽  
Chemical Stimuli ◽  
Low Levels ◽  
Normal Women

Previous investigation has demonstrated that progesterone, a hormone found in premenopausal women, is a ventilatory stimulant. However, fragmentary data suggest that normal women may have lower ventilatory responses to chemical stimuli than men, in whom progesterone is found at low levels. As male-female differences have not been carefully studied, we undertook a systematic comparison of resting ventilation and ventilatory responses to chemical stimuli in men and women. Resting ventilation was found to correlate closely with CO2 production in all subjects (r = 0.71, P less than 0.001), but women tended to have a greater minute ventilation per milliliter of CO2 produced (P less than 0.05) and consequently a lower CO2 partial pressure (PCO2) (men 35.1 +/- 0.5 Torr, women 33.2 +/- 0.5 Torr; P less than 0.02). Women were also found to have lower tidal volumes, even when corrected from body surface area (BSA), and greater respiratory frequency than comparable males. The hypoxic ventilatory response (HVR) quantitated by the shape parameter A was significantly greater in men [167 +/- 22 (SE)] than in women (109 +/- 13; P less than 0.05). In men this hypoxic response was found to correlate closely with O2 consumption (r = 0.75, P less than 0.001) but with no measure of size or metabolic rate in women. The hypercapnic ventilatory response, expressed as the slope of ventilation vs. PCO2, was also greater in men (2.30 +/- 0.23) than in women (1.58 +/- 0.19, P less than 0.05). Finally women tended to have higher ventilatory responses in the luteal than in the follicular menstrual phase, but this was significant only for HVR (P less than 0.05). Women, with relatively higher resting ventilation, have lower responses to hypoxia and hypercapnia.

Heart rate responses to apneic underwater diving and to breath holding in man

1963 ◽  
Vol 18 (5) ◽  
pp. 854-862 ◽  
Author(s):  
Albert B. Craig
Keyword(s):  
Heart Rate ◽  
Venous Return ◽  
Intrathoracic Pressure ◽  
Breath Holding ◽  
Breath Hold ◽  
Physiological Mechanisms ◽  
The Subject ◽  
Compression Chamber

Bradycardia is a response to apneic diving which man has in common with many other species. Slowing of the heart rate during diving was observed in children as well as adults and was as prominent in poor swimmers as in those subjects who were familiar with the water. The response was independent of depth down to 27 m, but could not be produced by simulated dives in a compression chamber. Diving in water implies several maneuvers, some of which were investigated during breath holding. It was observed that the tachycardia produced by breath holding at different Valsalva pressures was proportional to the increase of intrathoracic pressure. At equal pressures the tachycardia was less when the subject was in water than when in air. Other maneuvers which increased venous return at the beginning of the breath hold produced a bradycardia during the apnea, and conversely when venous return was impaired there was a tachycardia. The hypothesis is presented that diving bradycardia in man might be explainable in terms of already known physiological mechanisms. swimming; submersion Submitted on February 27, 1963

Validation of the Hexoskin wearable vest during lying, sitting, standing, and walking activities

2015 ◽  
Vol 40 (10) ◽  
pp. 1019-1024 ◽  
Author(s):  
Rodrigo Villar ◽  
Thomas Beltrame ◽  
Richard L. Hughson
Keyword(s):  
Heart Rate ◽  
Ventilatory Threshold ◽  
Minute Ventilation ◽  
Intraclass Correlation ◽  
Relative Magnitude ◽  
Mean Value ◽  
Maximal Heart Rate ◽  
Mean Values ◽  
Exercise Condition ◽  
The Mean

We tested the validity of the Hexoskin wearable vest to monitor heart rate (HR), breathing rate (BR), tidal volume (VT), minute ventilation, and hip motion intensity (HMI) in comparison with laboratory standard devices during lying, sitting, standing, and walking. Twenty healthy young volunteers participated in this study. First, participants walked 6 min on a treadmill at speeds of 1, 3, and 4.5 km/h followed by increasing treadmill grades until 80% of their predicted maximal heart rate. Second, lying, sitting, and standing tasks were performed (5 min each) followed by 6 min of treadmill walking at 80% of their ventilatory threshold. Analysis of each individual’s mean values under each resting or exercise condition by the 2 measurement systems revealed low coefficient of variation and high intraclass correlation values for HR, BR, and HMI. The Bland–Altman results from HR, BR, and HMI indicated no deviation of the mean value from zero and relatively small variability about the mean. VT and minute ventilation were provided in arbitrary units by the Hexoskin device; however, relative magnitude of change from Hexoskin closely tracked the laboratory standard method. Hexoskin presented low variability, good agreement, and consistency. The Hexoskin wearable vest was a valid and consistent tool to monitor activities typical of daily living such as different body positions (lying, sitting, and standing) and various walking speeds.

The diving physiology of bottlenose dolphins (Tursiops truncatus). I. Balancing the demands of exercise for energy conservation at depth

1999 ◽  
Vol 202 (20) ◽  
pp. 2739-2748 ◽  
Author(s):  
T.M. Williams ◽  
J.E. Haun ◽  
W.A. Friedl
Keyword(s):  
Heart Rate ◽  
Blood Lactate ◽  
Tursiops Truncatus ◽  
Marine Mammals ◽  
Bottlenose Dolphins ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Energetic Cost ◽  
Breath Holding ◽  
Breath Hold

During diving, marine mammals must rely on the efficient utilization of a limited oxygen reserve sequestered in the lungs, blood and muscles. To determine the effects of exercise and apnea on the use of these reserves, we examined the physiological responses of adult bottlenose dolphins (Tursiops truncatus) trained to breath-hold on the water surface or to dive to submerged targets at depths between 60 and 210 m. Changes in blood lactate levels, in partial pressures of oxygen and carbon dioxide and in heart rate were assessed while the dolphins performed sedentary breath-holds. The effects of exercise on breath-hold capacity were examined by measuring heart rate and post-dive respiration rate and blood lactate concentration for dolphins diving in Kaneohe Bay, Oahu, Hawaii. Ascent and descent rates, stroke frequency and swimming patterns were monitored during the dives. The results showed that lactate concentration was 1.1+/−0.1 mmol l(−1) at rest and increased non-linearly with the duration of the sedentary breath-hold or dive. Lactate concentration was consistently higher for the diving animals at all comparable periods of apnea. Breakpoints in plots of lactate concentration and blood gas levels against breath-hold duration (P(O2), P(CO2)) for sedentary breath-holding dolphins occurred between 200 and 240 s. In comparison, the calculated aerobic dive limit for adult dolphins was 268 s. Descent and ascent rates ranged from 1.5 to 2.5 m s(−1) during 210 m dives and were often outside the predicted range for swimming at low energetic cost. Rather than constant propulsion, diving dolphins used interrupted modes of swimming, with more than 75 % of the final ascent spent gliding. Physiological and behavioral measurements from this study indicate that superimposing swimming exercise on apnea was energetically costly for the diving dolphin but was circumvented in part by modifying the mode of swimming.

Temperature effect on the human dive response in relation to cold water near-drowning

1984 ◽  
Vol 56 (1) ◽  
pp. 202-206 ◽  
Author(s):  
J. S. Hayward ◽  
C. Hay ◽  
B. R. Matthews ◽  
C. H. Overweel ◽  
D. D. Radford
Keyword(s):  
Heart Rate ◽  
Water Temperature ◽  
Cold Water ◽  
Breath Holding ◽  
Breath Hold ◽  
Cold Stimulation ◽  
Near Drowning ◽  
Voluntary Hyperventilation ◽  
Dive Response ◽  
Breath Hold Duration

To facilitate analysis of mechanisms involved in cold water near-drowning, maximum breath-hold duration (BHD) and diving bradycardia were measured in 160 humans who were submerged in water temperatures from 0 to 35 degrees C at 5 degrees C intervals. For sudden submersion BHD was dependent on water temperature (Tw) according to the equation BHD = 15.01 + 0.92Tw. In cold water (0–15 degrees C), BHD was greatly reduced, being 25–50% of the presubmersion duration. BHD after brief habituation to water temperature and mild, voluntary hyperventilation was more than double that of sudden submersion and was also dependent on water temperature according to the equation BHD = 38.90 + 1.70Tw. Minimum heart rate during both types of submersions (diving bradycardia) was independent of water temperature. The results are pertinent to accidental submersion in cold water and show that decreased breath-holding capacity caused by peripheral cold stimulation reduces the effectiveness of the dive response and facilitates drowning. These findings do not support the postulate that the dive response has an important role in the enhanced resuscitatibility associated with cold water near-drowning, thereby shifting emphasis to hypothermia as the mechanism for this phenomenon.

Pulmonary diffusing capacities for oxygen-labeled CO2 and nitric oxide in rabbits

1998 ◽  
Vol 84 (2) ◽  
pp. 606-611 ◽  
Author(s):  
Hartmut Heller ◽  
Gabi Fuchs ◽  
Klaus-Dieter Schuster
Keyword(s):  
Nitric Oxide ◽  
Mass Spectrometry ◽  
Mean Value ◽  
Breath Holding ◽  
Breath Hold ◽  
Diffusing Capacity ◽  
Membrane Component ◽  
Single Breath ◽  
Partial Pressures

Heller, Hartmut, Gabi Fuchs, and Klaus-Dieter Schuster. Pulmonary diffusing capacities for oxygen-labeled CO2 and nitric oxide in rabbits. J. Appl. Physiol. 84(2): 606–611, 1998.—We determined the pulmonary diffusing capacity (Dl) for18O-labeled CO2(C18O2) and nitric oxide (NO) to estimate the membrane component of the respective gas conductances. Six anesthetized paralyzed rabbits were ventilated by a computerized ventilatory servo system. Single-breath maneuvers were automatically performed by inflating the lungs with gas mixtures containing 0.9% C18O2or 0.05% NO in nitrogen, with breath-holding periods ranging from 0 to 1 s for C18O2and from 2 to 8 s for NO. The alveolar partial pressures of C18O2and NO were determined by using respiratory mass spectrometry. Dl was calculated from gas exchange during inflation, breath hold, and deflation. We obtained values of 14.0 ± 1.1 and 2.2 ± 0.1 (mean value ± SD) ml ⋅ mmHg−1 ⋅ min−1for[Formula: see text]and Dl NO, respectively. The measured[Formula: see text]/Dl NOratio was one-half that of the theoretically predicted value according to Graham’s law (6.3 ± 0.5 vs. 12, respectively). Analyses of the several mechanisms influencing the determination of[Formula: see text]and Dl NOand their ratio are discussed. An underestimation of the membrane diffusing component for CO2 is considered the likely reason for the low[Formula: see text]/Dl NOratio obtained.

Effects of beta-adrenergic blockade on ventilation and gas exchange during exercise in humans

1983 ◽  
Vol 54 (5) ◽  
pp. 1306-1313 ◽  
Author(s):  
E. S. Petersen ◽  
B. J. Whipp ◽  
J. A. Davis ◽  
D. J. Huntsman ◽  
H. V. Brown ◽  
...  
Keyword(s):  
Heart Rate ◽  
Gas Exchange ◽  
Time Constant ◽  
Minute Ventilation ◽  
Work Rate ◽  
Beta Blockade ◽  
Adrenergic Blockade ◽  
O2 Uptake ◽  
Beta Adrenergic ◽  
Co2 Partial Pressure

The effects of beta-adrenergic blockade induced by intravenous propranolol hydrochloride (0.2 mg/kg) on ventilatory and gas exchange responses to exercise were studied during tests in which the work rate was either increased progressively or maintained at a constant load in six healthy young male subjects. Heart rate during exercise decreased by about 20% and cardiac output, as estimated by a modification of the method of Kim et al. (J. Appl. Physiol. 21: 1338–1344, 1966), by about 15%. The relation between work rate and O2 uptake (VO2) was unaffected by propranolol, whereas maximal O2 uptake (VO2max) decreased by 5% and the anaerobic threshold, estimated noninvasively, was lowered by 23%. The relations between CO2 output (VCO2) and end-tidal CO2 partial pressure (PCO2) and between VCO2 and minute ventilation (VE) were both unaffected. The time constants for changes of VO2, VCO2, and VE during on-transients from unloaded pedaling to either a moderate (ca. 50% VO2max) or a heavy (ca. 67% VO2max) work rate in the control studies were in agreement with previously reported values, i.e., 42, 60, and 69 s, respectively. beta-Blockade was associated with a significantly increased time constant for VO2 of 61 s but with less consistent and insignificant changes for VCO2 and VE. There was a small but significant increase of the time constant for heart rate from 40 to 45 s. It is concluded that propranolol exerts its primary influence during exercise on the cardiovascular system without any discernible effect on ventilatory control.

Background ventilatory stimulus as a determinant of load compensation

1989 ◽  
Vol 66 (3) ◽  
pp. 1352-1358 ◽  
Author(s):  
H. E. Greenberg ◽  
D. M. Rapoport ◽  
P. J. Gloeggler ◽  
R. M. Goldring
Keyword(s):  
Interindividual Variability ◽  
Ventilatory Response ◽  
Minute Ventilation ◽  
Normal Subjects ◽  
Co2 Production ◽  
Control Mechanisms ◽  
Co2 Response ◽  
Co2 Partial Pressure ◽  
Load Compensation ◽  
Resistive Loading

Compensation for inspiratory flow-resistive loading was compared during progressive hypercapnia and incremental exercise to determine the effect of changing the background ventilatory stimulus and to assess the influence of the interindividual variability of the unloaded CO2 response on evaluation of load compensation in normal subjects. During progressive hypercapnia, ventilatory response was incompletely defended with loading (mean unloaded delta VE/delta PCO2 = 3.02 +/- 2.29, loaded = 1.60 +/- 0.67 1.min-1.Torr-1 CO2, where VE is minute ventilation and PCO2 is CO2 partial pressure; P less than 0.01). Furthermore the degree of defense of ventilation with loading was inversely correlated with the magnitude of the unloaded CO2 response. During exercise, loading produced no depression in ventilatory response (mean delta VE/delta VCO2 unloaded = 20.5 +/- 1.9, loaded = 19.2 +/- 2.5 l.min-1.l-1.min-1 CO2 where VCO is CO2 production; P = NS), and no relationship was demonstrated between degree of defense of the exercise ventilatory response and the unloaded CO2 response. Differences in load compensation during CO2 rebreathing and exercise suggest the presence of independent ventilatory control mechanisms in these states. The type of background ventilatory stimulus should therefore be considered in load compensation assessment.

Responses to Exercise in Normobaric Hypoxia: Comparison of Elite and Recreational Ski Mountaineers

2014 ◽  
Vol 9 (6) ◽  
pp. 978-984 ◽  
Author(s):  
Raphael Faiss ◽  
Claudia von Orelli ◽  
Olivier Dériaz ◽  
Grégoire P. Millet
Keyword(s):  
Heart Rate ◽  
Oxygen Uptake ◽  
Maximal Oxygen Uptake ◽  
Hypobaric Hypoxia ◽  
Ventilatory Response ◽  
Minute Ventilation ◽  
Normobaric Hypoxia ◽  
Hypoxic Ventilatory Response ◽  
Treadmill Test ◽  
National Team

Purpose:Hypoxia is known to reduce maximal oxygen uptake (VO2max) more in trained than in untrained subjects in several lowland sports. Ski mountaineering is practiced mainly at altitude, so elite ski mountaineers spend significantly longer training duration at altitude than their lower-level counterparts. Since acclimatization in hypobaric hypoxia is effective, the authors hypothesized that elite ski mountaineers would exhibit a VO2max decrement in hypoxia similar to that of recreational ski mountaineers.Methods:Eleven elite (E, Swiss national team) and 12 recreational (R) ski mountaineers completed an incremental treadmill test to exhaustion in normobaric hypoxia (H, 3000 m, FIO2 14.6% ± 0.1%) and in normoxia (N, 485 m, FIO2 20.9% ± 0.0%). Pulse oxygen saturation in blood (SpO2), VO2max, minute ventilation, and heart rate were recorded.Results:At rest, hypoxic ventilatory response was higher (P < .05) in E than in R (1.4 ± 1.9 vs 0.3 ± 0.6 L · min−1 · kg−1). At maximal intensity, SpO2 was significantly lower (P < .01) in E than in R, both in N (91.1% ± 3.3% vs 94.3% ± 2.3%) and in H (76.4% ± 5.4% vs 82.3% ± 3.5%). In both groups, SpO2 was lower (P < .01) in H. Between N and H, VO2max decreased to a greater extent (P < .05) in E than in R (–18% and –12%, P < .01). In E only, the VO2max decrement was significantly correlated with the SpO2 decrement (r = .74, P < .01) but also with VO2max measured in N (r = .64, P < .05).Conclusion:Despite a probable better acclimatization to altitude, VO2max was more reduced in E than in R ski mountaineers, confirming previous results observed in lowlander E athletes.

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