Podcast
Questions and Answers
What is the physiological response to cold-water stimulation of the face and eyes?
What is the physiological response to cold-water stimulation of the face and eyes?
- Increased metabolic rate and shivering
- Increased blood flow to the extremities
- Increased respiratory rate and heart rate
- Apnea, bradycardia, and peripheral vasoconstriction (correct)
Which of the following factors contributes to the increased heat loss in water compared to air?
Which of the following factors contributes to the increased heat loss in water compared to air?
- Decreased heat convection in water
- Lower thermal conductivity of water
- Greater thermal conductivity of water (correct)
- Increased heat radiation in water
How does cold water affect muscle function and metabolism?
How does cold water affect muscle function and metabolism?
- Increased contraction velocity and improved neuromuscular coordination
- Decreased metabolic rate and increased reliance on carbohydrate metabolism
- Decreased contraction velocity and impaired neuromuscular coordination, leading to increased fatigue (correct)
- Increased metabolic rate and decreased lipolysis
Which of the following statements is TRUE about the diving reflex?
Which of the following statements is TRUE about the diving reflex?
Which of the following best describes the initial response to sudden partial cold water immersion?
Which of the following best describes the initial response to sudden partial cold water immersion?
What is the primary factor contributing to the increased heat loss in water compared to air?
What is the primary factor contributing to the increased heat loss in water compared to air?
Which of the following is NOT a consequence of cold water immersion on muscle function?
Which of the following is NOT a consequence of cold water immersion on muscle function?
What is the primary physiological effect of the diving reflex?
What is the primary physiological effect of the diving reflex?
What is the main topic discussed in the provided content?
What is the main topic discussed in the provided content?
What is the primary factor limiting the duration of apnea?
What is the primary factor limiting the duration of apnea?
Which of the following is NOT mentioned as a risk associated with apnea diving?
Which of the following is NOT mentioned as a risk associated with apnea diving?
What is the significance of the mention of 'variable weight' in the context of free diving?
What is the significance of the mention of 'variable weight' in the context of free diving?
According to the content, what is the primary stimulus for terminating a breath-hold and ascending?
According to the content, what is the primary stimulus for terminating a breath-hold and ascending?
What is the primary function of the 'respiratory drive' mentioned in the text?
What is the primary function of the 'respiratory drive' mentioned in the text?
What is the key difference between apnea and scuba diving?
What is the key difference between apnea and scuba diving?
What is the significance of Natalia Molchanova's achievements in the context of the provided content?
What is the significance of Natalia Molchanova's achievements in the context of the provided content?
What is the maximum depth a male aged 20-30 can safely dive to?
What is the maximum depth a male aged 20-30 can safely dive to?
What is the main respiratory drive when free diving?
What is the main respiratory drive when free diving?
What is the maximum recommended snorkel length?
What is the maximum recommended snorkel length?
What is the recommended snorkel diameter for children?
What is the recommended snorkel diameter for children?
What is the main risk associated with free diving (apnea diving)?
What is the main risk associated with free diving (apnea diving)?
What is 'VWT' as it relates to free diving?
What is 'VWT' as it relates to free diving?
At what depth does the partial pressure of oxygen (PiO2) reach 636 mmHg?
At what depth does the partial pressure of oxygen (PiO2) reach 636 mmHg?
What is the maximum safe depth that a male aged 50-60 can dive to?
What is the maximum safe depth that a male aged 50-60 can dive to?
What is the primary reason for visual distortion during oxygen poisoning?
What is the primary reason for visual distortion during oxygen poisoning?
Which of the following is a physiological effect of nitrogen narcosis?
Which of the following is a physiological effect of nitrogen narcosis?
What is the primary reason for the decrease in available air volume at greater depths?
What is the primary reason for the decrease in available air volume at greater depths?
Which of the following is NOT a symptom of oxygen poisoning?
Which of the following is NOT a symptom of oxygen poisoning?
At what depth does nitrogen narcosis begin to significantly affect judgment?
At what depth does nitrogen narcosis begin to significantly affect judgment?
How does helium help to prevent nitrogen narcosis?
How does helium help to prevent nitrogen narcosis?
Which of the following is NOT a risk associated with scuba diving?
Which of the following is NOT a risk associated with scuba diving?
What is the approximate resting ventilation rate per minute?
What is the approximate resting ventilation rate per minute?
What is the approximate available air volume at a depth of 40 meters?
What is the approximate available air volume at a depth of 40 meters?
Which of the following is a possible consequence of a closed glottis during the ascent in scuba diving?
Which of the following is a possible consequence of a closed glottis during the ascent in scuba diving?
What is the primary mechanism by which decompression sickness occurs in scuba diving?
What is the primary mechanism by which decompression sickness occurs in scuba diving?
Which of the following scenarios is MOST LIKELY to increase the risk of decompression sickness in a scuba diver?
Which of the following scenarios is MOST LIKELY to increase the risk of decompression sickness in a scuba diver?
What is the MOST LIKELY reason why persons with an open foramen ovale have a higher risk of decompression sickness during scuba diving?
What is the MOST LIKELY reason why persons with an open foramen ovale have a higher risk of decompression sickness during scuba diving?
Which of these is NOT a common symptom of decompression sickness?
Which of these is NOT a common symptom of decompression sickness?
What is the difference in risk between scuba diving and free diving with regards to lung tissue rupture during ascent?
What is the difference in risk between scuba diving and free diving with regards to lung tissue rupture during ascent?
Which of the following statements regarding diving is TRUE about the formation of nitrogen bubbles in the bloodstream?
Which of the following statements regarding diving is TRUE about the formation of nitrogen bubbles in the bloodstream?
Why is the risk of decompression sickness increased in individuals with an open foramen ovale?
Why is the risk of decompression sickness increased in individuals with an open foramen ovale?
Which of the following choices is TRUE about the risk of decompression sickness in free diving compared to scuba diving?
Which of the following choices is TRUE about the risk of decompression sickness in free diving compared to scuba diving?
Which of the following is the MOST EFFECTIVE way to minimize the risk of decompression sickness during scuba diving?
Which of the following is the MOST EFFECTIVE way to minimize the risk of decompression sickness during scuba diving?
How does increased hydrostatic pressure primarily affect the cardiovascular system during partial water immersion?
How does increased hydrostatic pressure primarily affect the cardiovascular system during partial water immersion?
While cardiac output increases during partial water immersion, why is there a reduction in heart rate?
While cardiac output increases during partial water immersion, why is there a reduction in heart rate?
What is the primary physiological reason for the increased respiratory muscle work during partial water immersion?
What is the primary physiological reason for the increased respiratory muscle work during partial water immersion?
What is the primary risk associated with colder water temperature during partial water immersion?
What is the primary risk associated with colder water temperature during partial water immersion?
Which of the following is NOT a direct physiological change caused by partial water immersion?
Which of the following is NOT a direct physiological change caused by partial water immersion?
Flashcards
Cold Shock
Cold Shock
A combination of reflexes occurring when immersed in cold water (< 25°C). Initial hyperventilation and increased air hunger result.
Diving Reflex
Diving Reflex
Physiological response to cold water on face, leading to apnoea, bradycardia, and vasoconstriction to extend survival time underwater.
Functional Residual Capacity (FRC)
Functional Residual Capacity (FRC)
The volume of air remaining in the lungs after a normal expiration, which increases during cold water immersion.
Heat Loss in Water vs. Air
Heat Loss in Water vs. Air
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Thermal Radiation
Thermal Radiation
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Epinephrine and Norepinephrine in Cold
Epinephrine and Norepinephrine in Cold
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Muscle Function in Cold
Muscle Function in Cold
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Apnoea in Diving Reflex
Apnoea in Diving Reflex
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Apnea
Apnea
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PaCO2
PaCO2
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PaO2
PaO2
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Hyperventilation
Hyperventilation
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Breathhold
Breathhold
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Motivation in diving
Motivation in diving
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Hyperbaric effects
Hyperbaric effects
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Blood gas changes
Blood gas changes
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TLC (Total Lung Capacity)
TLC (Total Lung Capacity)
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RV (Residual Volume)
RV (Residual Volume)
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Max depth (diving)
Max depth (diving)
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Pmax (Maximum Pressure)
Pmax (Maximum Pressure)
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Snorkel length
Snorkel length
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Valve considerations for snorkels
Valve considerations for snorkels
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Free diving (apnea diving)
Free diving (apnea diving)
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Main respiratory drive
Main respiratory drive
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Physiological changes in water immersion
Physiological changes in water immersion
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Impact of hydrostatic pressure
Impact of hydrostatic pressure
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Venous return
Venous return
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Stroke volume
Stroke volume
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Effects of cold water on heart rate
Effects of cold water on heart rate
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Lung Rupture
Lung Rupture
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Pneumothorax
Pneumothorax
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Decompression Sickness
Decompression Sickness
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Nitrogen Emboli
Nitrogen Emboli
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Visual Symptoms of DCS
Visual Symptoms of DCS
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Foramen Ovale Risk
Foramen Ovale Risk
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Pressure Release Mechanism
Pressure Release Mechanism
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Closed Glottis Effect
Closed Glottis Effect
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Local Pain from N2-Bubbles
Local Pain from N2-Bubbles
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SCUBA Diving Risks
SCUBA Diving Risks
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Volume without pressure
Volume without pressure
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Resting ventilation rate
Resting ventilation rate
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Oxygen poisoning
Oxygen poisoning
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Nitrogen narcosis
Nitrogen narcosis
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Partial pressure of oxygen (PiO2)
Partial pressure of oxygen (PiO2)
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SCUBA dangers
SCUBA dangers
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High PO2 symptoms
High PO2 symptoms
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Breathing underwater effects
Breathing underwater effects
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Helium replacement
Helium replacement
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Study Notes
Exercise Physiology I - AS24
- Course is about exercise physiology, specifically focusing on hyperbaric conditions (diving).
- Professor Christina M. Spengler, PhD, MD, teaches the course.
- The course covers physiological changes associated with water immersion (cold) and increasing hyperbaric environments (depth).
- Students will critically analyze the physiological similarities and differences free diving and scuba diving, including accident risks and preventative measures.
Learning Objectives
- Physiological changes during immersion and diving depth
- Similarities and differences between free diving and scuba diving
- Potential risks and safety measures for diving accidents
- Critically reflect on pathophysiological changes during diving
Cardio-Respiratory changes with Partial Water Immersion
- Venous return increases (↑)
- Stroke volume increases (↑) and heart rate decreases (↓), but overall, cardiac output increases (↑)
- Pulmonary blood volume increases (↑)
- Respiratory muscle work increases (↑)
- Diuresis increases (↑) in response to the above.
Cardio-Respiratory response to Cold Water Immersion (The Cold Shock)
- Combination of reflexes triggered by cold water (<25°C) on the body (excluding the head)
- Initial deep inspiration leads to substantial hyperventilation (the colder the water, the more pronounced the stimulus; peaks at approximately 10°C).
- Functional residual capacity (FRC) increases
- Increased air hunger.
Cardio-Respiratory changes with Full Water Immersion (The Diving Reflex)
- Physiological response to cold water stimulation of the face and eyes: Includes apnea, bradycardia, and peripheral vasoconstriction.
- Aim: Reduce oxygen consumption (VO2) and extend underwater survival time.
- Diving mammals demonstrate a more effective diving reflex compared to humans (children show a less effective response than adults)
Effects of Cold Water - Thermoregulation
- Heat transfer in water is significantly greater (26x) than in air..
- Overall, heat loss in water is 4x faster than in air.
- Immersion in 15°C water leads to body temperature decrease at a rate of -2.1°C/hour.
Effects of Cold Water - Muscle Function and Metabolism
- Contraction velocity decreases(↓)
- Neuromuscular coordination decreases(↓)
- Fatigue increases(↑)
- Increased risk of cardiac arrhythmia in cold water.
- Epinephrine and norepinephrine secretion increases(↑↑)
- Lipolysis increases (↑) leading to increased free fatty acids in the blood.
- Anaerobic glycolysis (muscle glycogen use) increases(↑)
Effects of Hyperbaric Conditions on Air-Filled Cavities
- Boyle's Law applies, impacting air-filled cavities (like sinuses, ears, lungs, and intestines) during diving
- Lung volume decreases with depth
- Lung volume is shown across depths in a graph
Barotrauma in Response to Hypobaric Conditions
- Equalize pressure or risks injuries
- The blockage may lead to pain, rupture of small vessels and membranes in the middle ear or sinuses, or rupture of the ear drum.
- Without proper equalization, blood vessels in the eyes and skin may be damaged, and eyes may even be displaced.
- Swim goggles provide no assistance to equalize pressure.
- Facemasks should include a nose opening to enable pressure equalization.
Free Diving (Apnea Diving) - Limits and Risks
- Breathhold limitations:
- Effects of hyperbaric conditions on lungs
- Snorkel considerations
Static Apnea - Guinness Book of World Records
- World records in breath-holding (e.g., Robert Foster, Budimir Sobat)
- Factors that influence apnea duration
Static Apnea - World Records (without oxygen breathing):
- Natalia Molchanova holding her breath for 9.02 minutes, and Stephane Mifsud for 11.35 minutes.
Limits to apnea
- Changes in blood gases (increase in PaCO2 and decrease in PaO2)
- Suppression of the respiratory drive and feedback.
- Motivation of the individual is an important factor.
Risk of Hyperventilation prior to Apnea
- Lower pCO2 levels can delay the stimulus to breathe.
- Reduced stimulus to breathe leads to the risk of unconsciousness
Diving depth and lung volume
- Lung volume decreases with increasing depth.
- Calculations for lung volume (L) at depths.
Diving depth and lung volume (Male and Female)
- Average Total Lung Capacity (TLC)
- Average Residual Volume (RV)
- Average Peak Expiratory flow (Pmax)
- Maximum depth according to these variables
Free diving (no limits) - World records (NLT)
- World records without any limitations other than those set by the athlete Tanya Streeter (160m) and Herbert Nisch (214m) world records
SCUBA Diving
- Invention of SCUBA by Jacques Cousteau and Emile Gagnan
- Incidents/risks in diving
SCUBA Diving - Additional Risks
- Oxygen poisoning
- Nitrogen narcosis
- Lung Injury
- Problems with decompression
Open-circuit demand SCUBA
- Detailed explanation of equipment and volume of air
- Calculation for time it takes to use air supplies at different depths
Gases under pressure during hyperbaric conditions
- O2 poisoning
- N2 narcosis
- Decompression complications
- Preventative and treatment methods
SCUBA Diving - additional risk: Oxygen poisoning
- Symptoms (visual distortion, rapid/shallow breathing, convulsions, seizures)
- Cause: Reduced oxygen removal from hemoglobin, decreased carbon dioxide uptake. This results in high oxygen pressure that causes vasoconstriction to cerebral vessels.
SCUBA Diving - additional risk: Nitrogen narcosis
- Nitrogen acts as anaesthetic.
- Symptoms worsen with increasing depth and pressure.
- Mitigation of symptom with different breathing gasses.
SCUBA Diving - additional risk: Lung injury
- Lung rupture during ascent (pneumothorax) due to rapidly decreasing pressure.
SCUBA Diving - additional risks: Bubbles, Emboli and Decompression sickness
- Bubbles, emboli and decompression sickness cause pain.
- Ascending too quickly releases dissolved nitrogen from liquid, causing bubbles that can cause various problems
SCUBA Diving - additional risk: Decompression sickness (special risk)
- Increased risk of N2-embolus to brain in divers with open foramen ovale (25% prevalence in population), is magnified threefold.
Prevention of decompression sickness
- Charts and dive computers that provide safe times for divers to ascend
- Treatment using hyperoxia and recompression chambers
Hyperbaric chambers
- Medical facilities that treat divers experiencing decompression sickness
Air-Rescue of divers with decompression sickness — a Challenge
- Air rescue procedures for divers
- Rega-Helicopter deployment in case of diver emergencies
Diving — Risks-Summary
- Summarize the overall risks of diving (free diving or SCUBA)
After this Lecture, ask yourself "Can I ...."
- List of potential questions to ask about diving
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Description
Explore the physiological responses elicited by cold-water stimulation, including the diving reflex and its effects on muscle function and metabolism. This quiz will delve into factors influencing heat loss in water compared to air and the implications for apnea diving. Test your knowledge on the body's adaptations to sudden cold exposure.
