Related Experiment Video
Updated: Oct 7, 2025
11:56
Training Rats to Voluntarily Dive Underwater: Investigations of the Mammalian Diving Response
Published on: November 12, 2014
12.5K
Vascular responses to simulated breath-hold diving involving multiple reflexes
Brandon G Fico1, Taha A Alhalimi1, Hirofumi Tanaka1
1Cardiovascular Aging Research Laboratory, Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, Texas.
Summary
Breath-hold diving significantly increases central artery compliance, enhancing the ability to buffer heart pulsations. This adaptation helps manage the cardiovascular challenges of breath-hold diving.
Area of Science:
- Cardiovascular Physiology
- Human Physiology
- Diving Medicine
Background:
- Breath-hold diving triggers a complex cardiovascular response, including hypertension, due to the diving reflex.
- Underwater swimming accentuates these hypertensive effects, posing a circulatory challenge for cushioning cardiac pulsations.
Purpose of the Study:
- To determine hemodynamic changes during simulated breath-hold diving.
- To test the hypothesis that central artery compliance is augmented during simulated breath-hold diving.
Main Methods:
- Twenty healthy adults underwent measurements of hemodynamics during rest, exercise, apnea, and simulated breath-hold diving.
- Central artery compliance was assessed by measuring carotid artery diameter changes in response to blood pressure fluctuations using ultrasound and arterial tonometry.
Main Results:
- Central artery compliance significantly increased during simulated diving compared to rest, exercise, and apnea alone.
- Simulated diving lowered heart rate to resting levels, attenuated cardiac output, and further elevated mean blood pressure and total peripheral resistance compared to other conditions.
Conclusions:
- Central artery compliance is augmented during simulated breath-hold diving.
- This increased compliance likely serves to buffer cardiac pulsations against the substantial hypertension induced by the diving reflex.
Related Concept Videos
01:17Other Factors Affecting Respiration Centers
988
Breathing is primarily an involuntary activity regulated by the brainstem respiratory centers. However, it can also be consciously controlled, allowing us to hold our breath or take deeper breaths when needed. This voluntary control is facilitated by the cerebral motor cortex, which bypasses the medullary centers to stimulate the respiratory muscles directly.
However, the ability to hold one's breath voluntarily is not limitless. When the CO2 concentration in the blood reaches a critical...
However, the ability to hold one's breath voluntarily is not limitless. When the CO2 concentration in the blood reaches a critical...
988
01:30Alterations in Respiration II
1.1K
There are numerous types of normal and abnormal respiration. Based on ventilatory movements, breathing patterns are classified as regular, deep, or shallow. Examples include Biot's breathing, Cheyne-Stokes respiration, Kussmaul's breathing, hyperventilation, and hypoventilation. Each pattern is clinically significant and aids in evaluating patients.
In Biot's breathing, the respiratory rate and depth are irregular, alternating between periods of deep gasping and apnea. Common causes...
In Biot's breathing, the respiratory rate and depth are irregular, alternating between periods of deep gasping and apnea. Common causes...
1.1K
01:21Mechanism of Breathing III: The Accessory Muscles
3.1K
The Role of Accessory Muscles in the Respiratory System
The respiratory system is a complex network that relies on primary respiratory muscles like the diaphragm, but also involves accessory muscles to enhance lung expansion and airflow during both inhalation and exhalation.
Enhancing Inhalation with Accessory Muscles:
Accessory muscles such as the sternocleidomastoid, scalene, intercostal, and abdominal muscles are crucial when additional respiratory effort is required, such as during deep...
The respiratory system is a complex network that relies on primary respiratory muscles like the diaphragm, but also involves accessory muscles to enhance lung expansion and airflow during both inhalation and exhalation.
Enhancing Inhalation with Accessory Muscles:
Accessory muscles such as the sternocleidomastoid, scalene, intercostal, and abdominal muscles are crucial when additional respiratory effort is required, such as during deep...
3.1K
01:25Hyperpnea and Hyperventilation
1.4K
Hyperventilation refers to a higher-than-normal rate and depth of breathing, often associated with anxiety attacks. This excessive breathing surpasses the body's need to expel CO2, leading to a condition known as hypocapnia - an unusually low level of carbon dioxide in the blood. Hypocapnia can constrict cerebral blood vessels, reducing blood flow to the brain, which may result in dizziness or fainting. Early signs include tingling and muscle spasms in the hands and face, caused by falling...
1.4K
01:29Assessment of Ventilation II: Respiratory Depth and Rhythm
1.9K
Respiratory Depth
Respiratory depth measures the volume of air inhaled or exhaled during a breath. It can vary from shallow to deep and typically remains consistent when a person is at rest or asleep. Occasionally, individuals will automatically inhale deeply, known as sighing, which inflates the lungs with more air than normal breathing.
To assess respiratory depth, observe the degree of chest excursion or movement:
Respiratory depth measures the volume of air inhaled or exhaled during a breath. It can vary from shallow to deep and typically remains consistent when a person is at rest or asleep. Occasionally, individuals will automatically inhale deeply, known as sighing, which inflates the lungs with more air than normal breathing.
To assess respiratory depth, observe the degree of chest excursion or movement:
1.9K
01:23Mechanism of Breathing II: Expiration
1.4K
The Physiology of Expiration: A Seamless Respiratory Process
Expiration, or exhaling, is a complex physiological process that begins as the inspiratory muscles begin to relax. This relaxation triggers a series of events that epitomize the efficiency of the respiratory system.
Mechanism of Expiration:
Expiration, or exhaling, is a complex physiological process that begins as the inspiratory muscles begin to relax. This relaxation triggers a series of events that epitomize the efficiency of the respiratory system.
Mechanism of Expiration:
1.4K