Vascular Responses to Simulated Breath-Hold Diving Involving Multiple Reflexes

Author(s):  
Brandon G Fico ◽  
Taha Ali Alhalimi ◽  
Hirofumi Tanaka

Breath-hold diving evokes a complex cardiovascular response. The degrees of hypertension induced by the diving reflex are substantial and accentuated by the underwater swimming. This condition provides a circulatory challenge to properly buffer and cushion cardiac pulsations. We determined hemodynamic changes during the diving maneuver. A total of 20 healthy young adults were studied. Hemodynamics were measured during exercise on a cycle ergometer, apnea, face immersion in cold water (trigeminal stimulation), and simulated breath-hold diving. Dynamic arterial compliance (measured by changes in carotid artery diameter via ultrasound divided by changes in carotid blood pressure as assessed by arterial tonometry) increased with simulated diving compared with rest (p=0.007) and was elevated compared with exercise and apnea alone (p<0.01). A significant increase in heart rate was observed with exercise, apnea, and facial immersion when compared with rest (p<0.001). However, simulated diving brought the heart rate down to resting levels. Cardiac output increased with all conditions (p<0.001), with an attenuated response during simulated diving compared with exercise and facial immersion (p<0.05). Mean blood pressure was elevated during all conditions (p<0.001), with a further elevation observed during simulated diving compared with exercise (p<0.001), apnea (p=0.016), and facial immersion (p<0.001). Total peripheral resistance was decreased during exercise and facial immersion compared with rest (p<0.001) but was increased during simulated diving compared with exercise (p<0.001), apnea (p=0.008), and facial immersion (p=0.003). We concluded that central artery compliance is augmented during simulated breath-hold diving to help buffer cardiac pulsations.

2002 ◽  
Vol 93 (3) ◽  
pp. 882-886 ◽  
Author(s):  
Johan P. A. Andersson ◽  
Mats H. Linér ◽  
Elisabeth Rünow ◽  
Erika K. A. Schagatay

This study addressed the effects of apnea in air and apnea with face immersion in cold water (10°C) on the diving response and arterial oxygen saturation during dynamic exercise. Eight trained breath-hold divers performed steady-state exercise on a cycle ergometer at 100 W. During exercise, each subject performed 30-s apneas in air and 30-s apneas with face immersion. The heart rate and arterial oxygen saturation decreased and blood pressure increased during the apneas. Compared with apneas in air, apneas with face immersion augmented the heart rate reduction from 21 to 33% ( P < 0.001) and the blood pressure increase from 34 to 42% ( P < 0.05). The reduction in arterial oxygen saturation from eupneic control was 6.8% during apneas in air and 5.2% during apneas with face immersion ( P < 0.05). The results indicate that augmentation of the diving response slows down the depletion of the lung oxygen store, possibly associated with a larger reduction in peripheral venous oxygen stores and increased anaerobiosis. This mechanism delays the fall in alveolar and arterial Po 2 and, thereby, the development of hypoxia in vital organs. Accordingly, we conclude that the human diving response has an oxygen-conserving effect during exercise.


2014 ◽  
Vol 2 (1) ◽  
Author(s):  
Rheiner V. Mandagi ◽  
Maya Moningka

Abstract: Human dive response aims to conserve oxygen. Direct contact of the water on the forehead, eyes and nose is a strong stimulus for which is innervated by the trigeminal nerve stimulation causes inhibition against respiratory and vasomotor centers and the activation of cardiac vagal motoneuron. The cardiovascular response that causes a decrease in the heart rate and vasoconstriction  Facial cold receptors more strongly activated by low water temperature (10 – 150C). The specific objective of this study was to analyze differences in pulse number of healthy male traditional diver before, while, and after simulated dives. This research is an experimental study with 20 analytical samples are housed in Malalayang 2 Data were analyzed using SPSS and Test T. The results of this study found the number of pulses during a breath hold and facial immersion in cold water was significantly lower than that before doing the activity (p = 0.0001) with 17.1±10.2 difference. The number after the pulse raised face of the water was significantly higher than the current hold your breath and facial immersion in cold water (p = 0.0001), with the difference in the amount of as much as 16.6±10.8 pulse. Conclusion : there are significant difference (p = 0.0001) number of pulses in healthy male traditional divers during the interim before and after the while doing simulations hold your breath and dive with facial immersion in cold water.                                                                                                         . Keywords : Pulse, Traditional Diving    Abstrak.Respon penyelaman manusia bertujuan untuk menghemat oksigen.Kontak langsung terhadap air pada dahi, mata dan hidung merupakan stimulus kuat karena dipersarafi oleh nervus trigeminus dimana stimulasi terhadapnya menyebabkan penghambatan pernafasan dan pengaktifan pusat vasomotor dan motoneuron vagal jantung.Respon kardiovaskuler ini yang menyebabkan penurunan denyut jantung dan terjadinya vasokontriksi.Reseptor dingin wajah lebih kuat teraktivasi dengan air temperatur rendah (10-150C).Tujuan khusus penelitian ini adalah menganalisa perbedaan jumlah denyut nadi laki-laki sehat penyelam tradisional sebelum, sementara, dan sesudah simulasi penyelaman.Penelitian ini merupakan jenis penelitian analitik eksperimental dengan 20 sampel yang bertempat di Malalayang 2. Data dianalisis dengan menggunakanSPSS dan Uji T. Hasil penelitian ini didapatkan jumlah denyut nadi saat melakukan tahan napas dan perendaman wajah dalam air dingin secara bermakna lebih rendah dibandingkan dengan sebelum melakukan kegiatan tersebut (p=0,0001) dengan perbedaan sebanyak 17,1+10,2. Jumlah denyut nadi sesudah wajah diangkat dari dalam air bermakna lebih tinggi daripada saat tahan napas dan perendaman wajah dalam air dingin (p=0,0001), dengan perbedaan jumlah denyut nadi sebanyak 16,6+10,8. Simpulan: ada perbedaan bermakna (p=0,0001) jumlah denyut nadi pada laki-laki sehat penyelam tradisional pada saat sebelum dengan sementara dan sesudah dengan sementara melakukan simulasi penyelaman dengan tahan napas dan perendaman wajah dalam air dingin. Kata Kunci: Denyut Nadi, Penyelaman Tradisional.


1963 ◽  
Vol 204 (2) ◽  
pp. 291-296 ◽  
Author(s):  
Edmundo Ashkar ◽  
William F. Hamilton

Seven dogs who ran well on a motor-driven treadmill were completely sympathectomized (including adrenal denervation) and subjected to unilateral vagotomy below the recurrent laryngeal branch. After recovery and retraining, a terminal experiment was performed in which, after completing the vagotomy, direct Fick determinations of cardiac output and continuous recordings of mean arterial pressure, heart rate, and oxygen consumption were made at rest and during increasing exercise The results were compared with those described by Barger et al. ( Am. J. Physiol. 184: 613, 1956) for normal dogs running at smaller speeds and grades. The heart rate of the operated dogs increased from 117 to 134. Barger's normal dogs doubled their heart rate. The A-V oxygen difference increased with work slightly less than Barger's normal dogs but the scatter in both groups was wide, as was the case with the stroke volume. The resting cardiac output was nearly normal in the operated dogs but increased only 34% with exercise, as against 200–300% in Barger's normals. Oxygen consumption increased about twofold as against the expected normal of three- to sevenfold. Peripheral resistance in both groups went down about 40%. The blood pressure in the normal increased substantially while that in the operated dogs fell about 20% to an average of 60 mm Hg.


2017 ◽  
Vol 38 (12) ◽  
pp. 928-936 ◽  
Author(s):  
Amanda Sardeli ◽  
Lucas do Carmo Santos ◽  
Marina Ferreira ◽  
Arthur Gáspari ◽  
Bruno Rodrigues ◽  
...  

AbstractIncrease in muscle mass and strength through resistance exercise (RE) has been highly recommended for healthy aging. On the other hand, RE could lead to acute cardiovascular risks prompted mainly by intense blood pressure elevations and cardiac autonomic imbalance. We compared the cardiovascular responses to three different RE protocols performed by 21 healthy elderly on a leg press machine. The protocols tested were high load (80% 1RM) until muscular failure (HL); low load (30% 1RM) until muscular failure (LL); low load, 30 repetitions followed by 3 sets of 15 repetitions, with 50% blood flow restriction (LL-BFR); and a control session (CON). Based on heart rate variability analysis, only LL kept parasympathetic indexes lower than CON at 30 min recovery. By finger photoplethysmography, LL-BFR prompted higher systolic and mainly diastolic blood pressure increments in many sets. The heart rate and cardiac output increase, and total peripheral resistance reduction following exercise were not different among RE protocols. There was no significant post-exercise hypotension and carotid arterial compliance changes. HL seems to be the safer protocol to be recommended for the healthy elderly, because it induces lower blood pressure increments and faster parasympathetic recovery compared to LL and LL-BFR.


Hypertension ◽  
2020 ◽  
Vol 75 (2) ◽  
pp. 524-531 ◽  
Author(s):  
John D. O’Connor ◽  
Matthew D. L. O’Connell ◽  
Hugh Nolan ◽  
Louise Newman ◽  
Silvin P. Knight ◽  
...  

Assessment of the cerebrovascular and cardiovascular response to standing has prognostic value for a range of outcomes in the older adult population. Studies generally attempt to control for standing speed differences by asking participants to stand in a specified time but little is known about the range of transition times observed. This study aimed to characterize how standing speed associates with cardiovascular and cerebrovascular measures following transition from supine to standing. Continuous cerebral oxygenation, heart rate, systolic and diastolic blood pressure were monitored for 3 minutes after transitioning from supine to standing. An algorithm was used to calculate the time taken to transition from existing Finometer data (from the height correction unit). Linear mixed-effects models were used to assess the influence of transition time on each of the signals while adjusting for covariates. Transition time ranged from 2 to 27 s with 17% of participants taking >10 s to stand. Faster transition was associated with a more extreme decrease 10 s after standing but improved recovery at 20 s for cerebral oxygenation and blood pressure. Standing faster was associated with an elevated heart rate on initiation of stand and a quicker recovery 10 to 20 s after standing. The speed of transitioning from supine to standing position is associated with cardiovascular and cerebrovascular response in the early period after standing (<40 s). Care should be taken in the interpretation of findings which may be confounded by standing speed and statistical adjustment for standing time should be applied where appropriate.


Entropy ◽  
2018 ◽  
Vol 20 (11) ◽  
pp. 860 ◽  
Author(s):  
Marcos Hortelano ◽  
Richard Reilly ◽  
Francisco Castells ◽  
Raquel Cervigón

Orthostatic intolerance syndrome occurs when the autonomic nervous system is incapacitated and fails to respond to the demands associated with the upright position. Assessing this syndrome among the elderly population is important in order to prevent falls. However, this problem is still challenging. The goal of this work was to determine the relationship between orthostatic intolerance (OI) and the cardiovascular response to exercise from the analysis of heart rate and blood pressure. More specifically, the behavior of these cardiovascular variables was evaluated in terms of refined composite multiscale fuzzy entropy (RCMFE), measured at different scales. The dataset was composed by 65 older subjects, 44.6% (n = 29) were OI symptomatic and 55.4% (n = 36) were not. Insignificant differences were found in age and gender between symptomatic and asymptomatic OI participants. When heart rate was evaluated, higher differences between groups were observed during the recovery period immediately after exercise. With respect to the blood pressure and other hemodynamic parameters, most significant results were obtained in the post-exercise stage. In any case, the symptomatic OI group exhibited higher irregularity in the measured parameters, as higher RCMFE levels in all time scales were obtained. This information could be very helpful for a better understanding of cardiovascular instability, as well as to recognize risk factors for falls and impairment of functional status.


2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Ke-Vin Chang ◽  
Wen-Shiang Chen ◽  
Ruey-Meei Wu ◽  
Ssu-Yuan Chen ◽  
Hsiu-Yu Shen ◽  
...  

The study aim was to assess sympathetic vasomotor response (SVR) by using pulsed wave Doppler (PWD) ultrasound in patients with multiple system atrophy (MSA) and correlate with the tilt table study. We recruited 18 male patients and 10 healthy men as controls. The SVR of the radial artery was evaluated by PWD, using inspiratory cough as a provocative maneuver. The response to head-up tilt was studied by a tilt table with simultaneous heart rate and blood pressure recording. The hemodynamic variables were compared between groups, and were examined by correlation analysis. Regarding SVR, MSA patients exhibited a prolonged latency and less heart rate acceleration following inspiratory cough. Compared with the tilt table test, the elevation of heart rate upon SVR was positively correlated to the increase of heart rate after head-up tilt. The correlation analysis indicated that the magnitude of blood pressure drop from supine to upright was positively associated with the SVR latency but negatively correlated with the heart rate changes upon SVR. The present study demonstrated that blunted heart rate response might explain MSA's vulnerability to postural challenge. PWD may be used to predict cardiovascular response to orthostatic stress upon head-up tilt in MSA patients.


1993 ◽  
Vol 265 (5) ◽  
pp. R1132-R1140 ◽  
Author(s):  
N. B. Olivier ◽  
R. B. Stephenson

Open-loop baroreflex responses were evaluated in eight conscious dogs before and during congestive heart failure to determine the effects of failure on baroreflex control of blood pressure, heart rate, cardiac output, and total peripheral resistance. Heart failure was induced by rapid ventricular pacing. Baroreflex function was determined by calculation of the range and gain of the open-loop stimulus-response relationships for the effect of carotid sinus pressure on blood pressure, heart rate, cardiac output, and total peripheral resistance. The range and gain of blood pressure responses were substantially reduced as early as 3 days after induction of heart failure (161 +/- 6 to 99 +/- 8 mmHg and -2.7 +/- 0.3 to -1.5 +/- 0.1, respectively) and remained depressed for the 21 days of heart failure. This depression in baroreflex control of blood pressure was associated with similar depressions in reflex range and gain for heart rate (125 +/- 9 to 78 +/- 11 beats/min and -2.05 +/- 0.2 to -1.16 +/- 0.2 beats/min, respectively) and cardiac output (1.74 +/- 0.2 to 0.46 +/- 0.2 l/min and -0.81 +/- 0.02 to -0.027 +/- 0.008 l/min, respectively). The group-averaged range and gain for reflex control of vascular resistance were not altered by heart failure. In three dogs, discontinuation of rapid ventricular pacing led to resolution of heart failure within 7 days and partial restoration of the range and gain of reflex control of blood pressure. We conclude that heart failure reversibly depresses baroreflex control of blood pressure principally through a concurrent reduction in reflex control of cardiac output, whereas reflex control of vascular resistance is not consistently affected.


2009 ◽  
Vol 297 (3) ◽  
pp. R769-R774 ◽  
Author(s):  
Steven J. Swoap ◽  
Margaret J. Gutilla

The laboratory mouse is a facultative daily heterotherm in that it experiences bouts of torpor under caloric restriction. Mice are the most frequently studied laboratory mammal, and often, genetically modified mice are used to investigate many physiological functions related to weight loss and caloric intake. As such, research documenting the cardiovascular changes during fasting-induced torpor in mice is warranted. In the current study, C57BL/6 mice were implanted either with EKG/temperature telemeters or blood pressure telemeters. Upon fasting and exposure to an ambient temperature (Ta) of 19°C, mice entered torpor bouts as assessed by core body temperature (Tb). Core Tb fell from 36.6 ± 0.2°C to a minimum of 25.9 ± 0.9°C during the fast, with a concomitant fall in heart rate from 607 ± 12 beats per minute (bpm) to a minimum of 158 ± 20 bpm. Below a core Tb of 31°C, heart rate fell exponentially with Tb, and the Q10 was 2.61 ± 0.18. Further, mice implanted with blood pressure telemeters exhibited similar heart rate and activity profiles as those implanted with EKG/temperature telemeters, and the fall in heart rate and core Tb during entrance into torpor was paralleled by a fall in blood pressure. The minimum systolic, mean, and diastolic blood pressures of torpid mice were 62.3 ± 10.2, 51.9 ± 9.2, 41.0 ± 7.5 mmHg, respectively. Torpid mice had a significantly lower heart rate (25–35%) than when euthermic at mean arterial pressures from 75 to 100 mmHg, suggesting that total peripheral resistance is elevated during torpor. These data provide new and significant insight into the cardiovascular adjustments that occur in torpid mice.


2017 ◽  
Vol 26 (2) ◽  
pp. 116-21
Author(s):  
Arif H.M. Marsaban ◽  
Aldy Heriwardito ◽  
I G.N.A.D. Yundha

Background: Increased blood pressure and heart rate are the most frequent response to laryngoscopy which sometimes causes serious complications. Laryngoscopy technique and tools modification lessen the nociceptive stimulation, thus preventing hemodynamic response. BURP maneuver is used to lower Cormack-Lehane level, but it can cause additional pain stimulation during laryngoscopy. The aim of this study was to compare the cardiovascular response and the need of BURP maneuver during laryngoscopy between CMAC® and conventional Macintosh.Methods: A randomized, single blinded, control trial was performed to 139 subjects who underwent general anesthesia with endotracheal tube. Subjects were randomised into a control group (conventional Macintosh) and an intervention group (CMAC®). The cardiovascular parameters (systolic, dyastolic, mean arterial pressure, and heart rate) were measured prior to induction (T1). Midazolam 0.05 mg/kg and Fentanyl 2 micrograms/kg were given 2 minutes before the induction. Moreover, they were given propofol 1 mg/kg followed by propofol infusion of 10 mg/kg/hour and Atracurium 0.8–1 mg/kg. After TOF-0 cardiovascular parameters (T2) were remeasured, it was proceeded to laryngoscopy. When Cormack-Lehane 1–2 was reached (with or without BURP maneuver), cardiovascular parameters were measured again (T3).Results: Unpaired T-test showed that cardiovascular response during laryngoscopy were significantly lower in the intervention group compared to the control group (p<0.05). The need of BURP maneuver was significantly lower in the CMAC® group compared to the Convensional Macintosh group (13.9% vs 40.3%; p<0.05).Conclusion: Cardiovascular response and BURP maneuver during laryngoscopy with CMAC® were significantly lower compared to conventional Macintosh.


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