Hyperventilation
A rather rapid breathing state, which contributes to a somewhat lower-than-normal level of carbon dioxide in the body, delays the energy-conserving effects of the mammalian diving response and enhances the binding of hemoglobin to oxygen, reducing the release of oxygen to the tissues (Bohr effect). Thus, the freediver exhausts his oxygen reserves more quickly and loses consciousness earlier....
Explanation:
Hyperventilation reduces the ability to hold his breath
Many of the oxygen-conserving mechanisms described in The Mammalian Diving Response (MDR) are triggered or supported by the high levels of carbon dioxide in the blood during apnea.
The lack of carbon dioxide suppresses the mammalian diving
response. Thus the body will not conserve energy (oxygen) to the same extent as during a breath-hold that begins with a normal level of carbon dioxide. After hyperventilation, the state of hypoxia is reached sooner than during a breath-hold that has been prepared by relaxation exercise with adequate normal ventilation.
Bohr effect
The decrease in carbon dioxide (hypocapnia) causes the blood to become more alkaline. This in turn makes the bond between hemoglobin and oxygen stronger! As a result, the oxygen bound to the blood is less likely to be released into the tissues. This is known as the Bohr effect.
Hyperventilation does not change the oxygen saturation level in the blood but reduces the carbon dioxide content. During breath holding, the symptoms of hypercapnia are delayed and 45% oxygen saturation can be reached before carbon dioxide levels exceed acceptable levels. This is why hyperventilation leads to loss of consciousness.
Barotrauma
Barotrauma is a general term for any physical damage caused by a difference in pressure inside one of the air-filled cavities of the body and the surrounding water pressure....
In diving, barotrauma can appear both during descent and ascent (reverse block).
Symptoms:
An eardrum perforation or rupture manifests itself with sharp pain. the patiant might also experience vertigo and loss of direction. If the eardrum is damaged, there will also be a temporary loss of hearing to a certain extent. As a consequence of an eardrum injury, water will enter the middle ear and there is a high risk of infection.
Middle Ear Barotrauma:
Blood is forced into the middle ear If the diver fail to equalize and do not stop descening, blood and other fluids might be forced into the middle ear, partially or even filling it. This is called a middle ear barotrauma. The fluid in the middle ear is a great risk of infection. Seek medical attention!
Symptoms:
A middle ear barotrauma causes sharp, sometimes extreme pain that might persist for days. Also, ear feels “full” and hearing is muffled or even completely lost. Sometimes the patiant feel like still having “water in the ears” the following day after freediving. In many cases, water is trapped in outer ear by earwax which needs an ear cleaning by a doctor. But if this is not the case, then might have suffered from middle barotrauma and need to seek medical assistance.
The best training for freediving
The best training for freediving encompasses a combination of physical conditioning, breath-hold techniques, mental preparation, and safety education....
Breath-Hold Techniques: Practicing breath-hold exercises to improve lung capacity, breath control, and relaxation underwater. This includes static apnea (holding one's breath without moving), dynamic apnea (swimming underwater on a single breath), and CO2 tolerance training.
Physical Fitness: Developing overall fitness, including cardiovascular endurance, strength, and flexibility, which can enhance performance and safety in freediving. Focus on exercises that improve lung function, such as swimming, yoga, and cardiovascular workouts.
Equalization Techniques: Learning and mastering equalization techniques to equalize pressure in the ears and sinuses as you descend, preventing discomfort and potential injuries. Techniques such as the Frenzel maneuver are commonly taught in freediving courses.
Safety and Rescue Skills: Understanding safety protocols, rescue techniques, and emergency procedures to ensure a safe diving experience. This includes training in buddy systems, recognizing signs of hypoxia or blackout, and performing rescue maneuvers.
Mental Preparation: Developing mental discipline, relaxation techniques, and focus to manage stress, anxiety, and adrenaline during dives. Visualization, meditation, and mindfulness practices can help improve mental resilience and concentration underwater.
Progressive Training: Gradually increasing dive depths and durations while respecting personal limits and listening to the body's signals. Incremental progression allows for adaptation and reduces the risk of injury or blackout.
Qualified Instruction: Seeking guidance from certified freediving instructors or training agencies to learn proper techniques, safety protocols, and best practices. Formal courses provide structured training, feedback, and assessment to ensure competency and safety.
Recovery and Rest: Prioritizing adequate rest, recovery, and hydration between training sessions to prevent fatigue, optimize performance, and reduce the risk of overtraining or injury.
Training session with Aboodfreediver
how freediving can potentially benefit the lungs?
Freediving can have positive effects on lung function and respiratory health, but it's essential to approach it safely and gradually, especially if you're new to the sport....
Increased Lung Capacity: Regular breath-hold training in freediving can help expand lung capacity over time. As you practice breath-holding exercises and underwater swimming, your lungs adapt to holding larger volumes of air, which can enhance overall respiratory function.
Improved Breath Control: Freediving requires precise breath control and relaxation techniques to optimize oxygen use and minimize air consumption during dives. These practices can help improve respiratory efficiency and breath-holding ability.
Enhanced Diaphragmatic Strength:Freediving involves using the diaphragm and intercostal muscles to control breathing and equalize pressure underwater. Training these muscles through breath-hold exercises and deep breathing techniques can strengthen them, potentially improving respiratory function.
Better Oxygen Utilization: Freediving promotes efficient oxygen utilization by the body, as divers learn to conserve oxygen and reduce the metabolic rate while underwater. This skill can have positive effects on overall respiratory health and aerobic endurance.
Stress Reduction: Engaging in freediving and spending time underwater can promote relaxation and stress reduction, which can have indirect benefits for respiratory health. Reduced stress levels may contribute to improved lung function and respiratory efficiency.
Pressure and RV-Depth
Your lungs reach residual volume (RV) after a maximum exhalation. This is the smallest size your lungs are used to and prepared to be at...
. [ Boyle’s Law ] now says that “(…) the volume of a gas is inversely proportional to the absolute pressure”,
which is often demonstrated with an air-filled balloon compressed at depth. During freediving, the air in your lungs reacts to pressure just like the balloon.
The deeper you go, the smaller becomes the volume of the inhaled air. At a certain depth, the volume of the inhaled air in your lungs will approach RV.
Getting close to RV can be felt as rising pressure on your upper torso, or, as a freediver proverb puts it, “RV is close when the elephant steps on your chest”.
You need to approach this level – or depth – with utmost care! Avoid jerky movements and control your descent speed by grabbing the diving rope if necessary.
Give your body time to adapt, and progress with training slowly over weeks and months. Failure depth is the depth where RV is reached and normal equalization will not work anymore.