Acidosis ACIDOSIS REDUCED ACIDOSIS Breath holding after an exhalation causes a decrease - PowerPoint Presentation

Acidosis ACIDOSIS

REDUCED ACIDOSISBreath holding after an exhalation causes a decrease to the concentration of oxygen to trigger increased lactic acid, therefore increased H+. At the same time, carbon dioxide also increases leading to an increased concentration of hydrogen ions to further acidify the blood. During breath holding CO2 increases to 50mmHg in the lungs.

REDUCED ACIDOSISFall of O2 and increase to CO2 greatly disturb the blood acid base balance. Causes a combined acidosis: metabolic and respiratory(metabolic acidosis decrease in pH associated with a fall in HCO3-) Due to a drop on pH and increase in H+

REDUCED ACIDOSISIncrease to CO2 increases HCO3- (as CO2 dissociate into H+ and HCO3-)However, the increased lactic acid causes a large accumulation of H+, therefore HCO3- tends to decrease. HCO3 - decreases as it buffers the excess of H+ generated by lactic acid.

REDUCED ACIDOSISNear infrared spectroscopy measures oxygen saturation within the muscle (SmO2)Amount of O2 lower in the muscleTissue hypoxia increases blood lactate concentrations CO2 also increases in the muscle. However, because of elevated aCO2, diffusion gradient between the tissues and blood is reduced, therefore CO2 release is slowed down and the gas accumulates in the muscle.

ANEROBIC TRAININGBoth the hypoxic and hypercapnic effects are responsible for the rise in H+ during breath holding. CO2 accumulates within muscle - converted into HCO3-, H+ ions are automatically produced A proportion of H+ ions are neutralised within the muscle by buffering substances which the most important are proteins and phosphate.

ANEROBIC TRAININGIncreased H+ ions in the muscle. Increased H+ ions in the bloodA STRONG ACIDITY WITHIN THE MUSCLE TISUE IS A MAJOR CONSEQUENCE OF EXERCISE WITH BH. IT IS THE MAIN CAUSE OF ADAPTATIONS THAT OCCUR AFTER BH TRAINING. Increased acidosis. When this occurs repeatedly, adaptation mechanisms are triggered to reduce acidosis. The buffer systems have the fastest action- enhanced blood and or muscle buffering capacity. Woorons

ANEROBIC TRAININGMain Buffering: Blood- Haemoglobin and bicarbonate Skeletal muscle- proteins, phosphates (60%) and to a lesser extent bicarbonate (18%)Possibly, enhanced buffering capacity in muscle compartments- lowering diffusion of H+ to the blood.Woorons X

ANEROBIC TRAININGIn breath holding following an exhalation, maximal lactate concentration (+ 2.35 ± 1.3 mmol.L-1 on average) and the rate of lactate accumulation in blood (+ 41.7 ± 39.4%) were higher at Post- than at Pre- in the three trials whereas they remained unchanged in CONTROLS. Woorons X, Mucci P, Richalet JP, Pichon A. Hypoventilation Training at Supramaximal Intensity Improves Swimming Performance. Med Sci Sports Exerc. 2016 Jun;48(6):1119-28

ANEROBIC TRAININGIncreased Lactate max reflects an improved anaerobic capacity and may be due to a greater ability to tolerate high concentrations of lactate and high level of acidosis, as reported after high-intensity training. Woorons X, Mucci P, Richalet JP, Pichon A. Hypoventilation Training at Supramaximal Intensity Improves Swimming Performance. Med Sci Sports Exerc. 2016 Jun;48(6):1119-28

FREE RADICALS

FREE RADICALSFree radicals are molecules generated by the breakdown of oxygen during metabolic activity. We all create a certain amount of free radicals through the very act of breathing to stay alive.

FREE RADICALS Highly reactive and attack other cells, causing damage to tissues and negatively affecting lipids, proteins and DNA. Implicated in ageing and a number of human diseases, including cancer. Devasagayam TP, Tilak JC, Boloor KK, Sane KS, Ghaskadbi SS, Lele RD. Free radicals and antioxidants in human health: current status and future prospects. J Assoc Physicians India. 2004;(Oct;52):794-804

FREE RADICALS Normal levels do not pose a problem since the body’s defence mechanism is able to neutralise the molecules with antioxidants.

FREE RADICALSOverbreathing and high-intensity exercise can cause an increased risk of muscle and tissue damage due to an overabundance of free radicals in the body.

FREE RADICALS Physical exercise increases oxidative stress and causes disruptions of the homeostasis. Training can have positive or negative effects on oxidative stress depending on training load, training specificity and the basal level of training. Moreover, oxidative stress seems to be involved in muscular fatigue and may lead to overtraining. Finaud J, Lac G, Filaire E. Oxidative Stress Relationship with Exercise and Training.Sports Med.2006;(36 (4)):327-358

FREE RADICALS Exhaustive and/or intense physical activity can induce diseases, injuries and chronic fatigue, which can lead to the overtraining syndrome, partially because of the toxicity of free radicals (FR). Finaud J, Lac G, Filaire E. Oxidative Stress Relationship with Exercise and Training. Sports Med .2006;(36 (4)):327-358

FREE RADICALSNine fit male subjects were studied before and after three months of running and were found to have significantly decreased levels of all circulating antioxidants except for ascorbate during training. Bergholm R, Mäkimattila S, Valkonen M, Liu ML, Lahdenperä S, Taskinen MR, Sovijärvi A, Malmberg P, Yki-Järvinen H. Intense physical training decreases circulating antioxidants and endothelium-dependent vasodilatation in vivo. Atherosclerosis.1999 Aug;(145(2)):341-9

FREE RADICALSThe conclusion reached was that “relatively intense aerobic training decreases circulating antioxidant concentrations”. Bergholm R, Mäkimattila S, Valkonen M, Liu ML, Lahdenperä S, Taskinen MR, Sovijärvi A, Malmberg P, Yki-Järvinen H. Intense physical training decreases circulating antioxidants and endothelium-dependent vasodilatation in vivo. Atherosclerosis.1999 Aug;(145(2)):341-9

FREE RADICALSIn what is considered to be one of the toughest foot races on Earth, competitors run the equivalent of six regular marathons over six days in the Sahara desert, during which they are required to carry their own food. Machefer G, Groussard C, Rannou-Bekono F, Zouhal H, Faure H, Vincent S, Cillard J, Gratas-Delamarche A. Extreme running competition decreases blood antioxidant defense capacity. Journal American College Nutrition.2004;(Aug;23(4)):358-64

FREE RADICALSBlood samples were taken 72 hours after completion of the race, with researchers noting a “significant alteration of the blood antioxidant defence capacity”, and concluding that, “such extreme competition induced an imbalance between oxidant and antioxidant protection”. Machefer G, Groussard C, Rannou-Bekono F, Zouhal H, Faure H, Vincent S, Cillard J, Gratas-Delamarche A. Extreme running competition decreases blood antioxidant defense capacity. Journal American College Nutrition.2004;(Aug;23(4)):358-64

FREE RADICALS The use of dietary antioxidants to reduce oxidative stress and exercise-induced muscle injury have met with mixed results to date. Clarkson PM. Antioxidants and physical performance. Critical Reviews of Food Science and Nutrition.1995 Jan;(35(1-2)):131-41 Clarkson PM, Thompson HS. Antioxidants: what role do they play in physical activity and health? American Journal Clinical Nutrition.2000 Aug;(72(2 Suppl)):637S-46SUrso ML, Clarkson PM. Oxidative stress, exercise, and antioxidant supplementation . Toxicology.2003 Jul 15;(189(1-2)):41-54

BREATH HOLDING TO REDUCE FREE RADICALS

BREATH HOLDING TO REDUCE FREE RADICALS After a three month breath hold program superimposed on the training of triathletes, “blood acidosis was reduced and the oxidative stress no more occurred” Fabrice Joulia, Jean Guillaume Steinberga, Marion Fauchera , Thibault Jaminc , Christophe Ulmera , Nathalie Kipsona , Yves Jammes . Breath-hold training of humans reduces oxidative stress and blood acidosis after static and dynamic apnea . Respir Physiol Neurobiol . 2003 ;(Aug 14;137(1)):19-27

BREATH HOLDING TO REDUCE FREE RADICALSTrained breath hold divers with an ability to hold their breath for up to 440 seconds during rest, were compared with a second group of non divers who had at most a 145 second breath hold time. Joulia F, Steinberg JG, Wolff F, Gavarry O, Jammes Y. Reduced oxidative stress and blood lactic acidosis in trained breath-hold human divers. Respir Physiol Neurobiol.2002 ;(Oct 23;133(1-2)):121-30

BREATH HOLDING TO REDUCE FREE RADICALSNormal breathing group showed an increase in blood lactic acid concentration, and oxidative stress. Diver group, the changes in both lactic acid and oxidative stress were markedly reduced after both breath holds and exercise . Joulia F, Steinberg JG, Wolff F, Gavarry O, Jammes Y. Reduced oxidative stress and blood lactic acidosis in trained breath-hold human divers. Respir Physiol Neurobiol.2002 ;(Oct 23;133(1-2)):121-30

BREATH HOLDING TO REDUCE FREE RADICALSConclusion: Humans who are involved in a long term training program of breath hold diving have reduced blood acidosis and oxidative stress following breath holds and exercise. Joulia F, Steinberg JG, Wolff F, Gavarry O, Jammes Y. Reduced oxidative stress and blood lactic acidosis in trained breath-hold human divers. Respir Physiol Neurobiol.2002 ;(Oct 23;133(1-2)):121-30

BREATH HOLDING TO REDUCE FREE RADICALSGroup of trained divers and a group of people with no diving experience at all. Results showed significant improvements in antioxidant activity across both groups, with little difference between the divers and non-divers. BULMER, ANDREW C. COOMBES, JEFF S.; SHARMAN, JAMES E., STEWART, IAN B. Effects of Maximal Static Apnea on Antioxidant Defenses in Trained Free Divers. Medicine & Science in Sports & Exercise.2008;40(7):1307-1313

BREATH HOLDING TO REDUCE FREE RADICALSOne small land-based mammal has managed to confound the overwhelming evidence to support the negative effects of oxidative stress. For the past few decades, scientists have studied the naked mole rat – a bald, blind creature that looks like a hot dog with teeth and lives for up to twenty-eight years, almost eight times longer than any other rodent.

BREATH HOLDING TO REDUCE FREE RADICALSThe naked mole rat lives in East Africa, where it is considered a pest by local farmers as it burrows tunnels underneath fields and eats vegetable crops.

BREATH HOLDING TO REDUCE FREE RADICALSThe breathing rate of the naked mole rat is very low in comparison to other rodents, and it lives in crowded colonies where there is little oxygen and high levels of carbon dioxide.

BREATH HOLDING TO REDUCE FREE RADICALSDespite living with high oxidative stress from a young age, the naked mole rat maintains good health and longevity, and in all the years this rather ugly animal has been studied, it has never been known to develop cancer. Buffenstein R.. Negligible senescence in the longest living rodent, the naked mole-rat: insights from a successfully aging species.. J Comp Physiol B.. 2008 May;(178(4)):439-45

BREATH HOLDING TO REDUCE FREE RADICALSEven when scientists have injected the mole rat with cancer-causing agents, the disease was resisted. Exactly why the naked mole rat is immune to cancer is unknown. Akshat Rathi . Cancer immunity of strange underground rat revealed. http://theconversation.com/cancer-immunity-of-strange-underground-rat-revealed-15358 (accessed 2nd Sep 2014).

BREATH HOLDING TO REDUCE FREE RADICALSResearchers have discovered that the negative affects of high oxidative stress may be offset by high carbon dioxide. Veselá A, Wilhelm J. The role of carbon dioxide in free radical reactions of the organism. Physiological Research. 2002;(51(4)):335-9

THE HEART

THE HEARTDr Jeremy Morris who studied the incidence of heart attacks in 31,000 transport workers. Bus conductors, averaging between 500 and 700 steps per day, had far less heart disease than their bus driving counterparts. Morris JN, Heady JA, Raffle PAB, et al. Coronary heart disease and physical activity of work. Lancet 1953;265(6795):1053-1057. 

THE HEARTIn 1863, the Swedish chemist, inventor and industrialist Alfred Nobel invented dynamite by combining the chemical nitro-glycerine with silica to form a more volatile paste.

THE HEARTIn the human body, nitro-glycerine – which is the same material used to make explosive – converts to the gas nitric oxide to provide amazing benefits for cardiovascular health.

THE HEARTSometimes referred to as the mighty molecule, nitric oxide is produced within the 100,000 miles of blood vessels throughout the human body including the paranasal sinuses surrounding the nasal cavity. Dr Louis Ignarro

THE HEARTNitric oxide sends a signal for the blood vessels to relax and widen. If there is too little nitric oxide, blood vessels narrow and the heart has to raise the pressure to send blood throughout the body.

THE HEARTPersistent high blood pressure or hypertension damages the arterial blood vessels, causing a build-up of plaque and cholesterol, and also causing blood clotting.

THE HEARTIf the blood clots, the obstruction causes the heart or brain to be deprived of blood and oxygen resulting in a heart attack or stroke.

THE HEARTNitric oxide plays a monumental role in human health by reducing cholesterol, reversing the build up of plaque in the blood vessels and helping to prevent blood clotting, all of which significantly increase the risk for heart attack and stroke.

THE HEARTAs we partake in physical exercise, blood flow increases and stimulates the inner lining of the blood vessels to produce more nitric oxide.

THE HEARTLow-intensity exercise –wasn’t enough to optimally increase blood flow. Conversely, high-intensity exercise – which includes vigorous activity at a fast pace – actually worsened blood flow. Goto C, Higashi Y, Kimura M, Noma K, Hara K, Nakagawa K, Kawamura M, Chayama K, Yoshizumi M, Nara I.. Effect of different intensities of exercise on endothelium-dependent vasodilation in humans: role of endothelium-dependent nitric oxide and oxidative stress. Circulation. 2003 Aug 5;(108(5)):530-5

THE HEARTModerate-intensity exercise –increased production of nitric oxide and provided a positive improvement of blood flow throughout the body. Goto C, Higashi Y, Kimura M, Noma K, Hara K, Nakagawa K, Kawamura M, Chayama K, Yoshizumi M, Nara I.. Effect of different intensities of exercise on endothelium-dependent vasodilation in humans: role of endothelium-dependent nitric oxide and oxidative stress. Circulation. 2003 Aug 5;(108(5)):530-5

THE HEARTUniversity of Exeter A study group of men aged between 19 and 38 drank half a litre of beetroot juice every day for a week. University of Exeter. (2009, August 7). Beetroot Juice Boosts Stamina, New Study Shows. http://www.sciencedaily.com/releases/2009/08/090806141520.htm (accessed 2nd Oct 2014).

THE HEARTDrinking the beetroot juice resulted in a “remarkable reduction” to the amount of oxygen required to perform exercise in comparison with a control group who drank water: the beetroot-drinking group were able to cycle 16% longer before tiring. University of Exeter. (2009, August 7). Beetroot Juice Boosts Stamina, New Study Shows. http://www.sciencedaily.com/releases/2009/08/090806141520.htm (accessed 2nd Oct 2014).

THE HEARTFurthermore, blood pressure within the beetroot group dropped (within normal levels), even though it wasn’t high to begin with. University of Exeter. (2009, August 7). Beetroot Juice Boosts Stamina, New Study Shows. http://www.sciencedaily.com/releases/2009/08/090806141520.htm (accessed 2nd Oct 2014).

The Heart“The reduction of oxygen required for submaximal exercise “following dietary supplementation with inorganic nitrate in the form of a natural food product cannot be achieved by any other known means, including long-term endurance exercise training”. University of Exeter. (2009, August 7). Beetroot Juice Boosts Stamina, New Study Shows. http://www.sciencedaily.com/releases/2009/08/090806141520.htm (accessed 2nd Oct 2014).

THE HEARTIn 1909, American physiologist Dr. Yandell Henderson produced ground-breaking work on the relationship between breathing and heart rate that remains relevant today. Henderson was director of the Laboratory of Applied Physiology at Yale University and considered an “expert on gases” at the time by The New York Times.

THE HEARTHenderson describes how he was able to regulate the heart rate of dogs to any rate he desired, from 40 beats or fewer per minute up to 200 or more. Henderson Y. Acapnia and shock- 1.Carbon Dioxide as a factor in the regulation of the heart rate. AJP - Legacy Content .February 1, 1908;21 no. 1():126-156

THE HEARTHypocapnia can affect cardiac functioning by decreasing the circulation of blood in the blood vessels and reducing blood flow to the heart. Rutherford, J.J. Clutton-Brock1, T.H. Parkes, M.J. 2005 Hypcapnia reduces the T wave of the electrocardiogram in normal human subjects. Am J Physiol Regul Integr Comp Physiol July 289:R148-R155; Hashimoto K , Okazaki K , Okutsu Y . 1990 Apr;39(4):437-41.The effect of hypocapnia and hypercapnia on myocardial oxygen tension in hemorrhaged dogs. Masui Kazmaier, S. Weyland, A. Buhre, W. et al. 1998 Effects of respiratory alkalosis and acidosis on myocardial blood flow and metabolism in patients with coronary artery disease. Anesthesiology 89:831-7.

THE HEARTSince low levels of carbon dioxide in the blood lead to a strengthening of the bond between the red blood cells and oxygen, the result is reduced delivery of oxygen to the heart. Rutherford, J.J. Clutton-Brock1, T.H. Parkes, M.J. 2005 Hypcapnia reduces the T wave of the electrocardiogram in normal human subjects. Am J Physiol Regul Integr Comp Physiol July 289:R148-R155; Hashimoto K , Okazaki K , Okutsu Y . 1990 Apr;39(4):437-41.The effect of hypocapnia and hypercapnia on myocardial oxygen tension in hemorrhaged dogs. Masui Kazmaier, S. Weyland, A. Buhre, W. et al. 1998 Effects of respiratory alkalosis and acidosis on myocardial blood flow and metabolism in patients with coronary artery disease. Anesthesiology 89:831-7.

CARDIAC ARREST

CARDIAC ARRESTWhen the heart beats abnormally – either too fast or too slow, or irregularly – this condition is termed arrhythmia. Cardiac arrest happens when the electrical signals that control the timing and rhythm of the heartbeat become completely chaotic.

CARDIAC ARRESTWhen this happens the heart is no longer able to effectively pump blood around the body, and unless treated promptly, death is inevitable. Jameson, J. N. et al 2005.ISBN  0-07-140235-7 Harrison's principles of internal medicine. New York: McGraw-Hill Medical Publishing Division.

CARDIAC ARRESTAn electrocardiogram (ECG) is a test used to interpret the electrical activity of the heart, assessing the rate and regularity of the heartbeat as well as the presence of any damage to the heart muscle. ST-depression T-wave inversion

CARDIAC ARRESTStudies have found that certain ECG changes in young athletes are common and usually reflect adaptations of the heart as a response to regular physical training. Corrado D. Electrical repolarization changes in young athletes: what is abnormal? http://spo.escardio.org/eslides/view.aspx?eevtid=33&id=2616 (accessed 15th April 2013 ).

CARDIAC ARRESTHowever, certain abnormal ECG readings, such as T-wave inversion, were found to be potential precursors to sudden and unexpected cardiac arrest during sport or exercise. Corrado D. Electrical repolarization changes in young athletes: what is abnormal? http://spo.escardio.org/eslides/view.aspx?eevtid=33&id=2616 (accessed 15th April 2013 ).

CARDIAC ARRESTST-segment depression is considered to be a sign of reduced circulation in the blood vessels of the heart, and it has been suggested that there is a link between ST-segment depression and the risk of sudden cardiac death. Kligfield P, Lauer M , Exercise Electrocardiogram Testing Beyond the ST Segment. Circulation.2006; 114: 2070-2082

CARDIAC ARRESTIn a study including 1,769 men, a total of 72 deaths occurred in the 18 years of follow-up – all of whom showed asymptomatic ST-segment depression on their ECG readings. Jari A. Laukkanen , Timo H. Mäkikallio, Rainer Rauramaa, Sudhir Kurl . (2009) Asymptomatic ST-segment depression during exercise testing and the risk of sudden cardiac death in middle-aged men: a population-based follow-up study. Eur Heart J (2009) 30 (5): 558-565

CARDIAC ARREST“Asymptomatic ST-segment depression was a very strong predictor of sudden cardiac death in men with any conventional risk factor but no previously diagnosed CHD.” Jari A. Laukkanen , Timo H. Mäkikallio , Rainer Rauramaa , Sudhir Kurl. (2009) Asymptomatic ST-segment depression during exercise testing and the risk of sudden cardiac death in middle-aged men: a population-based follow-up study. Eur Heart J (2009) 30 (5): 558-565.

CARDIAC ARREST474 healthy volunteers with no heart disease increased their breathing rate to over 30 breaths per minute for five minutes to create the effects of hyperventilation. Alexopoulos D, Christodoulou J, Toulgaridis T, Sitafidis G, Manias O, Hahalis G , Vagenakis AG . Repolarization abnormalities with prolonged hyperventilation in apparently healthy subjects: incidence, mechanisms and affecting factors. Eur Heart J. 1996 Sep;17(9):1432-7.

CARDIAC ARRESTECG readings reported abnormalities in 72 volunteers, including findings of ST-depression and T-wave inversion, with 80.5% of abnormalities occurring within the first minute of hyperventilation. Alexopoulos D, Christodoulou J, Toulgaridis T, Sitafidis G, Manias O, Hahalis G , Vagenakis AG . Repolarization abnormalities with prolonged hyperventilation in apparently healthy subjects: incidence, mechanisms and affecting factors. Eur Heart J. 1996 Sep;17(9):1432-7.

CARDIAC ARREST Interestingly, the study found that age, gender, smoking and hypertension did not influence the overall incidence of the abnormalities. Alexopoulos D, Christodoulou J , Toulgaridis T, Sitafidis G, Manias O, Hahalis G , Vagenakis AG . Repolarization abnormalities with prolonged hyperventilation in apparently healthy subjects: incidence, mechanisms and affecting factors. Eur Heart J. 1996 Sep;17(9):1432-7.

MYOCARDIAL INFARCTION

MYOCARDIAL INFARCTIONMyocardial infarction, otherwise known as a heart attack, occurs when blood flow to the heart is severely reduced or cut off altogether. This stoppage of blood results in oxygen starvation and damage or death to part of the heart muscle.

MYOCARDIAL INFARCTIONHeart attacks often occur during or following physical exercise or emotional stress.

MYOCARDIAL INFARCTION“In addition to causing peripheral and cerebral vasoconstriction, hyperventilation has also been shown to cause diminished coronary blood flow. Oxygen delivery to the myocardium and other tissues is further decreased in alkalosis because of increased haemoglobin oxygen affinity according to the Bohr effect”. Chelmowski, M.K, Keelan , M.H Jr. 1988 Hyperventilation and myocardial infarction. Chest. May;93(5): 1095-6.

MYOCARDIAL INFARCTIONFifty-five men were examined two months following a heart attack. Following a practice of breathing exercises, ventilation per minute significantly decreased from 18.5 to 9.8 litres. Vasiliauskas D, Jasiukeviciene L. 2004. Impact of a correct breathing stereotype on pulmonary minute ventilation, blood gases and acid-base balance in post-myocardial infarction patients. Eur J Cardiovasc Prev Rehabil. Jun;11(3):223-7.

MYOCARDIAL INFARCTIONCarbon dioxide increased from 33.2 mmHg to 44.2 mmHg (normal CO2 is 40 mmHg.) Vasiliauskas D, Jasiukeviciene L. 2004. Impact of a correct breathing stereotype on pulmonary minute ventilation, blood gases and acid-base balance in post-myocardial infarction patients. Eur J Cardiovasc Prev Rehabil. Jun;11(3):223-7 .

MYOCARDIAL INFARCTIONThe paper recommended that breathing retraining could be an additional rehabilitation measure after heart attacks. Vasiliauskas D, Jasiukeviciene L. 2004. Impact of a correct breathing stereotype on pulmonary minute ventilation, blood gases and acid-base balance in post-myocardial infarction patients. Eur J Cardiovasc Prev Rehabil . Jun;11(3):223-7

MYOCARDIAL INFARCTION “Breathing retraining has lasting effects on respiratory physiology and is highly correlated with a reduction in reported functional cardiac symptoms.” Deguire, S. Gervirtz , R. Kawahara, Y. And Maguire, W. 1992 Hyperventilation syndrome and the assessment of treatment for functional cardiac symptons. American Journal of Cardiology. Sep 1;70(6):673-7.

HYPERVENTILATION DURING CPR

HYPERVENTILATION DURING CPRIn 13 adults receiving CPR, the average ventilation was 30 breaths per minute. None of the 13 adults survived. Aufderheide , T.P. Lurie, K.G. 2004 Death by hyperventilation: a common and life-threatening problem during cardiopulmonary resuscitation. Critical Care Medicine. Sep;32(9 Suppl ):S345-51.

HYPERVENTILATION DURING CPRSurvival rates in the groups were as follows: six out of seven pigs treated with 12 breaths per minute, one out of seven treated with 30 breaths per minute and one out of seven pigs treated with 30 breaths per minute plus carbon dioxide. Aufderheide, T.P. Lurie, K.G. 2004 Death by hyperventilation: a common and life-threatening problem during cardiopulmonary resuscitation. Critical Care Medicine. Sep;32(9 Suppl ):S345-51.

HYPERVENTILATION DURING CPR“Additional education of CPR providers is urgently needed to reduce these newly identified and deadly consequences of hyperventilation during CPR.” Aufderheide , T.P. Lurie, K.G. 2004 Death by hyperventilation: a common and life-threatening problem during cardiopulmonary resuscitation. Critical Care Medicine. Sep;32(9 Suppl):S345-51.

HYPERVENTILATION DURING CPR“hyperventilation was common, and that the persistently high airway pressures are likely to have a detrimental effect on blood flow during CPR.” O'Neill J.F. Deakin, C.D. 2007 Apr;73(1):82-5. Epub 2007 Feb 7. Do we hyperventilate cardiac arrest patients? Resuscitation.

BREATH HOLDING BREAKPOINT BREATH HOLDING BREAK POINT

HOW TO MEASURE UPPER LIMIT OF BREATHLESSNESS- Inspiratory muscle activity was the final common pathway determining the breakpoint. The onset of electrical activity during a breath holding period is closely related to the alveolar Pc02.Agostoni E. Diaphragm activity during breath holding: factors related to its onset. J Appl Physiol 1963; 18:30-6

WHAT DETERMINES HOW LONG WE CAN HOLD OUR BREATH? Edward Schneider, a pioneer of breath-holding research described a subject lasting for 15 minutes and 13 seconds under comparable conditions in the 1930s. Parkes, Scientific American, April 2012

WHAT DETERMINES HOW LONG WE CAN HOLD OUR BREATH? 1959 physiologist Hermann Rahn used a combination of unusual methods—slowing his metabolism, hyperventilating, filling his lungs with pure oxygen, and more to hold his breath for almost 14 minutes.Parkes , Scientific American, April 2012

WHAT DETERMINES HOW LONG WE CAN HOLD OUR BREATH? The lungs alone should contain enough oxygen to sustain us for about four minutes. In the same vein, carbon dioxide does not accumulate to toxic levels in the blood quickly enough to explain the one-minute limit. Parkes, Scientific American, April 2012

WHAT DETERMINES HOW LONG WE CAN HOLD OUR BREATH? Breath-holding divers feel compelled to draw a breath well before they actually run out of oxygen. As Schneider observed, “it is practically impossible for a man at sea level to voluntarily hold his breath until he becomes unconscious .”Parkes , Scientific American, April 2012

WHAT DETERMINES HOW LONG WE CAN HOLD OUR BREATH? The break point may depend very much on stimuli that reach the brain from the diaphragm. During such a lengthy contraction, the brain might subconsciously perceive the unusual signals from the diaphragm as vaguely uncomfortable at first but eventually as intolerable, causing the break point. The automatic rhythm then regains control. Parkes, Scientific American, April 2012

BREATH HOLDING BREAKPOINTThe precise mechanisms explaining breath-holding and causing the breath at breakpoint are unknown. There are several useful reviews (Mithoefer, 1965; Godfrey & Campbell, 1968, 1969; Porter, 1970; Campbell & Guz , 1981; Lin, 1982; Nunn, 1987).  Parkes MJ. Breath-holding and its breakpoint. Exp Physiol. 2006 Jan;91(1):1-15.

BREATH HOLDING BREAKPOINTDuring breath-holding, the arterial or end tidal partial pressure of oxygen falls below its normal level of ∼100 mmHg and that of carbon dioxide rises above its normal level of ∼40 mmHg. Parkes MJ . Breath-holding and its breakpoint. Exp Physiol. 2006 Jan;91(1):1-15.

BREATH HOLDING BREAKPOINTAt breakpoint from maximum inflation in air, the PetO2 is typically 62 ± 4 mmHg and the PetCO2 is typically 54 ± 2 mmHg, and the longer the breath-hold the more they change. Parkes MJ. Breath-holding and its breakpoint. Exp Physiol.  2006 Jan;91(1):1-15.

BREATH HOLDING BREAKPOINTIt is remarkable that adults normally cannot breath-hold consistently to unconsciousness, even under laboratory supervision. Nunn (1987) estimates that consciousness in normal adults is lost at PO2 levels below ∼27 mmHg and  PCO2 levels between 90 and 120 mmHg. Parkes MJ. Breath-holding and its breakpoint. Exp Physiol.  2006 Jan;91(1):1-15.

BREATH HOLDING BREAKPOINTBreakpoint levels close to these have been reported, e.g. PetO2 levels as low as 24 mmHg, PetCO2 levels as high as 91 mmHg and breath-hold durations of 14 min or more (Schneider 1930, Ferris et al 1946, Klocke and Rahn 1959) Parkes MJ. Breath-holding and its breakpoint. Exp Physiol. 2006 Jan;91(1):1-15.