Scuba Diving Physiology: How Diving Affects Our Bodies

Diving is an incredible adventure that takes us into a world unlike any other. But as you descend beneath the surface, your body faces unique challenges due to the increased pressure, changes in gas absorption, and the effects of temperature. Understanding how diving affects your body is essential not only for safety but also for enjoying each dive to the fullest.

In this post, we’ll explore the key physiological changes your body undergoes while diving, how to manage them, and how to ensure safe and enjoyable dives.

Pressure and Its Effects on the Body

One of the most significant factors affecting your body underwater is pressure. As you descend, the weight of the water above you increases, and for every 10 meters (33 feet) you go down, the pressure increases by one atmosphere (ATM).

Key Areas Affected by Pressure:

• Ears and Sinuses: As pressure increases, the air spaces in your ears and sinuses are compressed. This is why equalizing your ears is so important during a dive. If you don’t equalize properly, the pressure can cause pain, and in extreme cases, barotrauma (damage to tissues caused by pressure changes). The same principle applies to your mask—if you don’t equalize the pressure inside it, you can experience mask squeeze, which is uncomfortable and can leave marks on your face. How to Manage: Equalize early and often during your descent. Pinch your nose and gently blow through it (Valsalva maneuver), or try swallowing or wiggling your jaw to equalize the pressure in your ears.
• Lungs: The air in your lungs is also compressed as you descend. This is why you should never hold your breath while diving—if you ascend while holding your breath, the expanding air in your lungs can cause a dangerous condition known as a lung over-expansion injury. This can lead to serious complications like pneumothorax (collapsed lung) or arterial gas embolism (air bubbles entering the bloodstream). How to Manage: Always breathe continuously and never hold your breath. Maintain a slow, controlled ascent to allow your lungs to safely adjust to the changing pressure.

Nitrogen Absorption and Decompression Sickness

While you’re underwater, the increased pressure causes more nitrogen from the air you breathe to dissolve into your tissues. This isn’t a problem at depth, but if you ascend too quickly, the nitrogen can form bubbles in your blood and tissues, leading to decompression sickness (DCS), also known as “the bends.”

Symptoms of Decompression Sickness:

• Joint and muscle pain
• Dizziness or confusion
• Numbness or tingling
• Fatigue

How to Prevent DCS:

• Ascend Slowly: One of the most important rules in diving is to ascend at a controlled rate. The recommended ascent rate is no faster than 18 meters (60 feet) per minute.
• Use a Dive Computer or Dive Tables: These tools help you track your nitrogen levels and ensure you’re within safe limits. Always stick to the no-decompression limits (NDL) and take safety stops during your ascent, especially after deeper or longer dives.
• Stay Hydrated: Dehydration increases the risk of DCS, so make sure to drink plenty of fluids before and after your dive.

Gas Narcosis

At depths greater than 30 meters (100 feet), the increased pressure can cause gas to have a narcotic effect, commonly known as gas narcosis. This can impair your judgment, slow your reaction time, and make you feel overly relaxed or euphoric, sometimes referred to as “the rapture of the deep.”

How to Manage gas Narcosis:

• Stay Shallow: Narcosis generally isn’t an issue at recreational depths, but if you’re diving deep, be aware of the potential for it to occur.
• Ascend: If you start feeling the effects of narcosis, simply ascend to a shallower depth, and the symptoms will usually go away quickly.

Conclusion: Knowledge Is Power

Understanding how diving affects your body is a critical part of being a safe, responsible diver. By being aware of the changes your body undergoes underwater—from the effects of pressure and nitrogen absorption to staying warm and hydrated—you can prevent potential risks and fully enjoy your dives.

For more tips on diving physiology and safety, check out our other resources at OSEA Divers Cozumel. Happy diving!