scholarly journals Physiology, pathophysiology and (mal)adaptations to chronic apnoeic training: a state-of-the-art review

2021 ◽  
Author(s):  
Antonis Elia ◽  
M. Gennser ◽  
P. S. Harlow ◽  
Matthew J. Lees
Keyword(s):  
Preliminary Evidence ◽  
Breath Holding ◽  
Breath Hold ◽  
Long Term Effects ◽  
Diving Response ◽  
Recreational Sport ◽  
Modern Times ◽  
Military Campaigns ◽  
World Records

AbstractBreath-hold diving is an activity that humans have engaged in since antiquity to forage for resources, provide sustenance and to support military campaigns. In modern times, breath-hold diving continues to gain popularity and recognition as both a competitive and recreational sport. The continued progression of world records is somewhat remarkable, particularly given the extreme hypoxaemic and hypercapnic conditions, and hydrostatic pressures these athletes endure. However, there is abundant literature to suggest a large inter-individual variation in the apnoeic capabilities that is thus far not fully understood. In this review, we explore developments in apnoea physiology and delineate the traits and mechanisms that potentially underpin this variation. In addition, we sought to highlight the physiological (mal)adaptations associated with consistent breath-hold training. Breath-hold divers (BHDs) are evidenced to exhibit a more pronounced diving-response than non-divers, while elite BHDs (EBHDs) also display beneficial adaptations in both blood and skeletal muscle. Importantly, these physiological characteristics are documented to be primarily influenced by training-induced stimuli. BHDs are exposed to unique physiological and environmental stressors, and as such possess an ability to withstand acute cerebrovascular and neuronal strains. Whether these characteristics are also a result of training-induced adaptations or genetic predisposition is less certain. Although the long-term effects of regular breath-hold diving activity are yet to be holistically established, preliminary evidence has posed considerations for cognitive, neurological, renal and bone health in BHDs. These areas should be explored further in longitudinal studies to more confidently ascertain the long-term health implications of extreme breath-holding activity.

The human spleen as an erythrocyte reservoir in diving-related interventions

2002 ◽  
Vol 92 (5) ◽  
pp. 2071-2079 ◽  
Author(s):  
Kurt Espersen ◽  
Hans Frandsen ◽  
Torben Lorentzen ◽  
Inge-Lis Kanstrup ◽  
Niels J. Christensen
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Indirect Method ◽  
Hemoglobin Concentration ◽  
Breath Holding ◽  
Breath Hold ◽  
Peripheral Blood Flow ◽  
Diving Response ◽  
Human Spleen ◽  
The Face

Twelve subjects without and ten subjects with diving experience performed short diving-related interventions. After labeling of erythrocytes, scintigraphic measurements were continuously performed during these interventions. All interventions elicited a graduated and reproducible splenic contraction, depending on the type, severity, and duration of the interventions. The splenic contraction varied between ∼10% for “apnea” (breath holding for 30 s) and “cold clothes” (cold and wet clothes applied on the face with no breath holding for 30 s) and ∼30–40% for “simulated diving” (simulated breath-hold diving for 30 s), “maximal apnea” (breath holding for maximal duration), and “maximal simulated diving” (simulated breath-hold diving for maximal duration). The strongest interventions (simulated diving, maximal apnea, and maximal simulated diving) elicited modest but significant increases in hemoglobin concentration (0.1–0.3 mmol/l) and hematocrit (0.3–1%). By an indirect method, the splenic venous hematocrit was calculated to 79%. No major differences were observed between the two groups. The splenic contraction should, therefore, be included in the diving response on equal terms with bradycardia, decreased peripheral blood flow, and increased blood pressure.

scholarly journals THE IMPACT OF THE COVID-19 PANDEMIC ON THE PROFITABILITY OF LARGE COMMERICAL BANKS IN THE REPUBLIC OF NORTH MACEDONIA

2021 ◽  
Vol 14(63) (2) ◽  
pp. 79-84
Author(s):  
Fitim Deari ◽  
Keyword(s):  
Commercial Banks ◽  
Preliminary Evidence ◽  
Long Term Effects ◽  
Commerical Banks ◽  
The Republic ◽  
Using Data ◽  
The Impact ◽  
Profitability Ratios

The purpose of this study is to investigate the impact of the current Covid-19 pandemic on profitability ratios of large commercial banks in the Republic of North Macedonia. By using data over the period 2004 – 2020, ten profitability indicators are examined. These indicators are investigated by comparing their values before and during the Covid-19 pandemic. Overall, the study reveals a preliminary evidence that large commercial banks are affected by the Covid-19 pandemic. So far, profitability of large banks has not changed significantly due to Covid-19 and they keep satisfactory profitability levels. However, this impact should be investigated furthermore in next studies because the current pandemic has long-term effects.

Breath-hold diving as a brain survival response

2013 ◽  
Vol 4 (3) ◽  
Author(s):  
Zeljko Dujic ◽  
Toni Breskovic ◽  
Darija Bakovic
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Respiratory Muscles ◽  
Breath Hold ◽  
Diving Response ◽  
Compensatory Mechanisms ◽  
Physiological Adaptations ◽  
O2 Delivery ◽  
World Records ◽  
The Brain

AbstractElite breath-hold divers are unique athletes challenged with compression induced by hydrostatic pressure and extreme hypoxia/hypercapnia during maximal field dives. The current world records for men are 214 meters for depth (Herbert Nitsch, No-Limits Apnea discipline), 11:35 minutes for duration (Stephane Mifsud, Static Apnea discipline), and 281 meters for distance (Goran Čolak, Dynamic Apnea with Fins discipline). The major physiological adaptations that allow breath-hold divers to achieve such depths and duration are called the “diving response” that is comprised of peripheral vasoconstriction and increased blood pressure, bradycardia, decreased cardiac output, increased cerebral and myocardial blood flow, splenic contraction, and preserved O2 delivery to the brain and heart. This complex of physiological adaptations is not unique to humans, but can be found in all diving mammals. Despite these profound physiological adaptations, divers may frequently show hypoxic loss of consciousness. The breath-hold starts with an easy-going phase in which respiratory muscles are inactive, whereas during the second so-called “struggle” phase, involuntary breathing movements start. These contractions increase cerebral blood flow by facilitating left stroke volume, cardiac output, and arterial pressure. The analysis of the compensatory mechanisms involved in maximal breath-holds can improve brain survival during conditions involving profound brain hypoperfusion and deoxygenation.

scholarly journals Sports-related lung injury during breath-hold diving

2016 ◽  
Vol 25 (142) ◽  
pp. 506-512 ◽  
Author(s):  
Tanja Mijacika ◽  
Zeljko Dujic
Keyword(s):  
Lung Injury ◽  
Lung Damage ◽  
Strenuous Exercise ◽  
Alveolar Haemorrhage ◽  
Breath Holding ◽  
Breath Hold ◽  
Pulmonary Barotrauma ◽  
Large Populations ◽  
Acute And Chronic Effects

The number of people practising recreational breath-hold diving is constantly growing, thereby increasing the need for knowledge of the acute and chronic effects such a sport could have on the health of participants. Breath-hold diving is potentially dangerous, mainly because of associated extreme environmental factors such as increased hydrostatic pressure, hypoxia, hypercapnia, hypothermia and strenuous exercise.In this article we focus on the effects of breath-hold diving on pulmonary function. Respiratory symptoms have been reported in almost 25% of breath-hold divers after repetitive diving sessions. Acutely, repetitive breath-hold diving may result in increased transpulmonary capillary pressure, leading to noncardiogenic oedema and/or alveolar haemorrhage. Furthermore, during a breath-hold dive, the chest and lungs are compressed by the increasing pressure of water. Rapid changes in lung air volume during descent or ascent can result in a lung injury known as pulmonary barotrauma. Factors that may influence individual susceptibility to breath-hold diving-induced lung injury range from underlying pulmonary or cardiac dysfunction to genetic predisposition.According to the available data, breath-holding does not result in chronic lung injury. However, studies of large populations of breath-hold divers are necessary to firmly exclude long-term lung damage.

The physiology and pathophysiology of human breath-hold diving

2009 ◽  
Vol 106 (1) ◽  
pp. 284-292 ◽  
Author(s):  
Peter Lindholm ◽  
Claes EG Lundgren
Keyword(s):  
Decompression Sickness ◽  
Nitrogen Pressure ◽  
Breath Hold ◽  
High Nitrogen ◽  
Diving Response ◽  
Human Breath ◽  
Physiological Limits ◽  
World Records ◽  
Physiological Reactions ◽  
Breath Hold Duration

This is a brief overview of physiological reactions, limitations, and pathophysiological mechanisms associated with human breath-hold diving. Breath-hold duration and ability to withstand compression at depth are the two main challenges that have been overcome to an amazing degree as evidenced by the current world records in breath-hold duration at 10:12 min and depth of 214 m. The quest for even further performance enhancements continues among competitive breath-hold divers, even if absolute physiological limits are being approached as indicated by findings of pulmonary edema and alveolar hemorrhage postdive. However, a remarkable, and so far poorly understood, variation in individual disposition for such problems exists. Mortality connected with breath-hold diving is primarily concentrated to less well-trained recreational divers and competitive spearfishermen who fall victim to hypoxia. Particularly vulnerable are probably also individuals with preexisting cardiac problems and possibly, essentially healthy divers who may have suffered severe alternobaric vertigo as a complication to inadequate pressure equilibration of the middle ears. The specific topics discussed include the diving response and its expression by the cardiovascular system, which exhibits hypertension, bradycardia, oxygen conservation, arrhythmias, and contraction of the spleen. The respiratory system is challenged by compression of the lungs with barotrauma of descent, intrapulmonary hemorrhage, edema, and the effects of glossopharyngeal insufflation and exsufflation. Various mechanisms associated with hypoxia and loss of consciousness are discussed, including hyperventilation, ascent blackout, fasting, and excessive postexercise O2 consumption. The potential for high nitrogen pressure in the lungs to cause decompression sickness and N2 narcosis is also illuminated.

scholarly journals More complaints than findings - Long-term pulmonary function in children and adolescents after COVID-19

2021 ◽  
Author(s):  
Leona Knoke ◽  
Anne Schlegtendal ◽  
Christoph Maier ◽  
Lynn Eitner ◽  
Thomas Luecke ◽  
...  
Keyword(s):  
Pulmonary Function ◽  
Children And Adolescents ◽  
Respiratory Symptoms ◽  
Severe Infection ◽  
Preliminary Evidence ◽  
Long Term Effects ◽  
Diffusion Capacity ◽  
Persistent Symptoms ◽  
Abnormal Pulmonary Function

Background: The frequency of persistent symptoms after coronavirus disease 2019 (COVID-19) in adults varies from 4.5% to 87%. Pulmonary function can also show long-term impairment in adults: 10% of hospitalised adults had reduced spirometry values, and 24% had decreased diffusion capacity. To date, only preliminary evidence is available on persistent respiratory sequelae in children and adolescents, therefore our objective was to examine the long-term effects of COVID-19 on pulmonary function in this age group. Methods: Multiple-breath washout, body plethysmography, and diffusion capacity testing were performed after an average of 2.6 months (range 0.4-6.0) following COVID-19 in 73 children and adolescents (age 5-18 years) with different disease severity. Cases were compared to 45 controls with and without infection within six months prior to assessment after exclusion of severe acute respiratory coronavirus-2 infection (SARS-CoV-2). Results: Of the 19 patients (27.1%) who complained about persistent or newly emerged symptoms since COVID-19, 8 (11.4%) reported respiratory symptoms. Comparing patients with COVID-19 to controls, no significant differences were detected in frequency of abnormal pulmonary function (COVID-19: 12, 16.4%; controls: 12, 27.7%; OR 0.54, 95% CI 0.22-1.34). Only two patients with persistent respiratory symptoms showed abnormal pulmonary function. Multivariate analysis revealed reduced forced vital capacity (p=0.045) in patients with severe infection regardless of SARS-CoV-2 infection. Discussion: Pulmonary function is rarely impaired in children and adolescents after COVID-19, except of those with severe infection. The discrepancy between persistent respiratory symptoms and normal pulmonary function suggests a different underlying pathology such as dysfunctional breathing.

scholarly journals The Long-Term Effects of Developmental Hypoxia on Cardiac Mitochondrial Function in Snapping Turtles

2021 ◽  
Vol 12 ◽  
Author(s):  
Gina L. J. Galli ◽  
Ilan M. Ruhr ◽  
Janna Crossley ◽  
Dane A. Crossley
Keyword(s):  
Embryonic Development ◽  
Mitochondrial Function ◽  
Hypoxia Tolerance ◽  
Breath Hold ◽  
Ros Production ◽  
Long Term Effects ◽  
Anoxic Environments ◽  
The Common ◽  
Mitochondrial Remodeling

It is well established that adult vertebrates acclimatizing to hypoxic environments undergo mitochondrial remodeling to enhance oxygen delivery, maintain ATP, and limit oxidative stress. However, many vertebrates also encounter oxygen deprivation during embryonic development. The effects of developmental hypoxia on mitochondrial function are likely to be more profound, because environmental stress during early life can permanently alter cellular physiology and morphology. To this end, we investigated the long-term effects of developmental hypoxia on mitochondrial function in a species that regularly encounters hypoxia during development—the common snapping turtle (Chelydra serpentina). Turtle eggs were incubated in 21% or 10% oxygen from 20% of embryonic development until hatching, and both cohorts were subsequently reared in 21% oxygen for 8 months. Ventricular mitochondria were isolated, and mitochondrial respiration and reactive oxygen species (ROS) production were measured with a microrespirometer. Compared to normoxic controls, juvenile turtles from hypoxic incubations had lower Leak respiration, higher P:O ratios, and reduced rates of ROS production. Interestingly, these same attributes occur in adult vertebrates that acclimatize to hypoxia. We speculate that these adjustments might improve mitochondrial hypoxia tolerance, which would be beneficial for turtles during breath-hold diving and overwintering in anoxic environments.

scholarly journals Multiple sclerosis and bilingualism

2020 ◽  
Author(s):  
Fraibet Aveledo ◽  
Yolanda Higueras ◽  
Theodoros Marinis ◽  
Arpita Bose ◽  
Christos Pliatsikas ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Inhibitory Control ◽  
Executive Control ◽  
Flanker Task ◽  
Preliminary Evidence ◽  
Long Term Effects ◽  
Monitoring Cost ◽  
The Impact ◽  
First Time

Abstract It has been suggested that bilingualism is beneficial for executive control and could have positive long-term effects by delaying the onset of symptoms of degenerative diseases. This research investigates, for the first time, the impact of bilingualism on executive control (monitoring and inhibitory control) in individuals with Multiple Sclerosis (MS), a neurodegenerative disease which commonly causes deficiencies in the cognitive system. Bilingual and monolingual adults, with and without an MS diagnosis, performed a flanker task with two degrees of monitoring demands (high monitoring vs. low monitoring). Results showed that bilingual MS patients had inhibitory control and monitoring abilities that were similar to healthy bilingual controls. In contrast, monolingual MS patients showed similar inhibitory control but significantly worse monitoring abilities compared to monolingual healthy controls. We propose that the similar behaviour between bilingual groups suggests that bilingualism might counteract cognitive deficits related to MS, especially with respect to monitoring. The high monitoring cost observed in monolingual patients seems related to underlying deficits in monitoring and possibly switching, executive control abilities commonly impaired in MS patients from early stages. Our findings provide some preliminary evidence for the cognitive reserve hypothesis in bilingual MS patients.

Ovarian Dysfunction in Fetally Irradiated Beagles

1977 ◽  
Vol 35 ◽  
pp. 658-659
Author(s):  
T. M. Seed ◽  
M. H. Sanderson ◽  
D. L. Gutzeit ◽  
T. E. Fritz ◽  
D. V. Tolle ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Low Dose ◽  
Long Term Effects ◽  
Ovarian Dysfunction ◽  
Dose Rates ◽  
Highly Sensitive ◽  
Microscopic Evaluation ◽  
Ovarian Pathology ◽  
Normal Offspring

The developing mammalian fetus is thought to be highly sensitive to ionizing radiation. However, dose, dose-rate relationships are not well established, especially the long term effects of protracted, low-dose exposure. A previous report (1) has indicated that bred beagle bitches exposed to daily doses of 5 to 35 R 60Co gamma rays throughout gestation can produce viable, seemingly normal offspring. Puppies irradiated in utero are distinguishable from controls only by their smaller size, dental abnormalities, and, in adulthood, by their inability to bear young.We report here our preliminary microscopic evaluation of ovarian pathology in young pups continuously irradiated throughout gestation at daily (22 h/day) dose rates of either 0.4, 1.0, 2.5, or 5.0 R/day of gamma rays from an attenuated 60Co source. Pups from non-irradiated bitches served as controls. Experimental animals were evaluated clinically and hematologically (control + 5.0 R/day pups) at regular intervals.

Sign in / Sign up

Export Citation Format

Share Document