Depth Progression Calculator

Your body needs time to adapt to increasing water pressure. Jumping from 10 meters to 25 meters in a single session puts enormous strain on your ears, sinuses, and lungs. Progressive training gives your tissues time to become more flexible and resilient, which reduces your risk of barotrauma and makes each dive feel natural rather than forced.

Consistent, gradual depth increases also train your nervous system. Your mammalian dive reflex gets stronger with repeated exposure, meaning your heart rate drops more efficiently and your body conserves oxygen better at depth. Rushing this process actually slows your progress because your body stays in a stress response instead of adapting.

Think of it like strength training. You would not load a barbell with twice your max on the first day. You add weight in small increments, let your body recover, and come back stronger. Freediving works the same way.

At the surface, you experience 1 atmosphere (ATM) of pressure. Every 10 meters of depth adds another atmosphere. So at 10 meters you are at 2 ATM, at 20 meters you are at 3 ATM, and at 30 meters you are at 4 ATM.

This pressure compresses every air space in your body. Your lungs, which hold about 6 liters at the surface, shrink to 3 liters at 10 meters, 2 liters at 20 meters, and 1.5 liters at 30 meters. This follows Boyle's Law, which states that as pressure doubles, volume halves.

Your middle ear and sinuses also contain air. If you do not equalize the pressure in these spaces, the surrounding tissue gets pulled inward, causing pain and potential injury. This is why equalization technique is the single most important skill in freediving. Master it before chasing depth.

Your body gives clear signals when it is not ready for more depth. Learning to read these signals and respect them is what separates safe freedivers from reckless ones.

• Equalization pain or difficulty. If you cannot equalize easily and without force, do not descend further. Forcing equalization can rupture your eardrum.
• Strong contractions before the turn. If your diaphragm is contracting hard before you even reach your target depth, your body is telling you that oxygen is running low. Turn early.
• Tingling, tunnel vision, or confusion. These are signs of hypoxia and mean you are dangerously low on oxygen. Surface immediately using controlled, efficient movements.
• Chest tightness or discomfort. Lung squeeze can occur when you exceed the depth your chest wall and diaphragm can handle. Back off and build up gradually.
• Fatigue or feeling off. If you did not sleep well, are dehydrated, or just do not feel right, that day is not the day to push limits. Train at a comfortable depth and save the personal bests for when your body is ready.

A safety diver is not optional. It is the most important piece of equipment in freediving. Shallow water blackout can happen to anyone, at any level, and it happens without warning. One moment you are ascending, the next moment you are unconscious. Without a trained buddy watching you, that situation can be fatal within minutes.

A good safety diver meets you at a predetermined depth during your ascent, watches your face and body language for signs of hypoxia, and is ready to grab you and bring you to the surface if anything goes wrong. They know how to perform rescue breathing and how to keep your airway clear.

On every BADA trip, Minseo (PADI Master Freediver) acts as your safety diver. You will never dive without proper supervision, and the pace is always matched to your ability. That is the only way to train safely and actually enjoy the process.