Freediving and health

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The power of the dive reflex (DR) in daily life

Although the dive reflex (DR) is designed as a survival mechanism under extreme conditions, we can use it to manage stress. In our hectic lives, the activity of the sympathetic nervous system often increases, which leads to a faster heart rate and higher breathing frequency.

By consciously using bradycardia (slowing the heart rate) through breathing techniques, we can break this pattern and reduce stress.

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    CO₂ Familiarization & The Therapeutic Effect

    • Fact 1:
      CO₂ (carbon dioxide) is a byproduct of our metabolism.
      At rest, the air we breathe in consists of about 21% oxygen (O₂) and 79% nitrogen (N₂).
      The air we exhale contains about 16% O₂, 5% CO₂, and 79% N₂.
    • Fact 2:
      Breath-holding (apnea) increases CO₂ levels in the blood.
    • Fact 3:
      The increased CO₂ levels during breath-holding are one of the triggers of the dive reflex (Mammalian Dive Response).
      This can lead to a reduction in heart rate (bradycardia).
    • Fact 4:
      Overbreathing/hyperventilation (HV) lowers CO₂ levels in the blood (the opposite of what happens during apnea).
    • Fact 5:
      Hyperventilation increases the heart rate (the opposite effect of apnea).
    • Fact 6:
      Hyperventilation should never be used in freediving.
      It is considered very dangerous because a freediver with low CO₂ levels will not feel the urge to breathe.
      Since our body detects hypercapnia (high CO₂ levels) rather than hypoxia (low O₂ levels), the diver may lose consciousness without any warning.

    However, hyperventilation is not just a problem for freedivers.

    Panic attacks, traumatic experiences, and extreme stress can trigger hyperventilation.
    During a hyperventilation attack, people may develop tachycardia (increased heart rate), experience dizziness, and possibly have oxygen deprivation in the tissues (due to the Bohr effect*).

    From a Physiological Perspective:
    The only way to reverse this situation is to do the opposite: hypoventilation or apnea (conscious breath-holding).

    The biggest obstacle to this therapy is that people believe they cannot hold their breath.
    Their brain activates hyperventilation as a false mechanism, making them feel like they need more air.

    Solution:

    1. Education about the physiology of breath-holding and its benefits.
    2. Gradual CO₂ Familiarization
      • By slowly acclimating their body and mind to higher CO₂ levels, individuals can integrate breath-holding exercises into their daily routine.
      • Over time, they can use these techniques to prevent hyperventilation and even control an attack once it begins.
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