Medical fitness to dive: realistic standards

The RSTC medical standard

Most agencies use RSTC standards. These rules guide PADI, SSI, and CMAS instructors when they ask about your health. You will see these questions on a standard dive medical form. It is not a doctor’s diagnosis. It is a screening tool.

Some people fear the form. They worry a single answer ends their hobby. This is rarely true. Most conditions allow for diving if you provide medical proof. You must be honest with your instructor.

I saw a diver in Koh Tao in 2018 fail a check because he hid his history. He had a minor heart murmur that his doctor had already cleared. Because he lied, the dive center had to deny him entry for safety reasons. Honesty is the only way to stay safe underwater.

Asthma and respiratory health

Diving with asthma is possible. You do not need to be perfectly clear. However, your lungs must function well under pressure. A doctor must confirm your airway is stable.

Your peak flow meter is a key tool. If your numbers stay consistent, you are likely fine. Most doctors look for stability over several weeks. They want to see that your medication works effectively.

Avoid diving if you feel wheezy. Even a small cough can become a problem at 20 m. Pressure changes affect how air moves through your bronchioles. If you struggle to breathe on land, stay on the boat.

Managing diabetes underwater

Type 1 diabetes requires a plan. It does not mean you cannot dive. You just need a very strict insulin protocol. This helps prevent hypoglycemia during a long descent.

Blood sugar monitoring is vital. You should check your levels before every single dive. A sudden drop at 15 m is dangerous. You cannot easily eat a snack while wearing a regulator.

Many divers use continuous glucose monitors. These devices help track trends in real time. If you are managing your levels well, you are fit to dive. Always tell your buddy about your condition.

Heart conditions and diving

Diving heart condition risks are real. Pressure changes put extra stress on the cardiovascular system. A doctor must evaluate your specific cardiac history. They look at how your heart handles exertion.

Some murmurs are harmless. Other issues require a specialist’s review. If you have had a stent or surgery, get a written note. This note should state you are cleared for depths up to 30 m.

I remember a diver in Komodo with a mild arrhythmia. He was careful and stayed shallow. He used a dive computer to monitor his heart rate closely. He never pushed himself into heavy currents or high stress.

Conditions that require clearance

Certain issues demand a doctor’s signature. These are not automatic bans. They just require professional verification. You cannot self-diagnose these conditions.

Epilepsy is a major concern. Uncontrolled seizures underwater are fatal. Most doctors will not clear you if you have had recent seizures. This is a hard rule for safety.

Recent pneumothorax is another red flag. A collapsed lung is a serious medical event. You must wait until a physician confirms your lung is fully healed. Diving too soon can cause a repeat collapse.

Severe COPD also limits your options. If your lung capacity is low, you may struggle. Some divers with mild COPD dive successfully. They just need to follow very conservative profiles.

The PFO question

A Patent Foramen Ovale (PFO) is a hole in the heart. It exists in about 25% of the population. Many people never know they have it. It can increase your risk of decompression sickness.

If you get DCS frequently, test for a PFO. This test uses an ultrasound called a bubble study. It checks if bubbles pass from one side of the heart to the other. Knowing this helps you plan safer dives.

Some divers choose to avoid deep repetitive dives. They might also avoid heavy currents. If you have a PFO, talk to a hyperbaric specialist. They can give you specific depth limits.

When to see a hyperbaric doctor

Standard GPs might not know diving physics. They may see a heart condition and say no. This is why a hyperbaric doctor is better. They understand how pressure affects the body.

These specialists look at specific risks. They know about nitrogen loading and gas solubility. A single signature from them can clear many hurdles. It is worth the extra cost.

A consultation might cost $150 to $300 USD. This is a small price for peace of mind. Do not argue with a local dive instructor. They are not doctors. They follow the rules provided by the RSTC.

Practical steps for your next trip

Prepare your paperwork early. Do not wait until you arrive at Anilao to find a doctor. Most clinics in tourist areas are not specialists. You need a formal letter of fitness.

Get your medical records organized. Include recent blood tests and lung function results. Having these in a digital folder is very helpful. It makes the process much faster for your physician.

Check your insurance policy too. Ensure it covers diving-related medical issues. Some policies have a 50% limit on certain activities. You want full coverage if something goes wrong.

If you have a known condition, tell your dive center. They need to know how to help you. This is not about being banned from the water. It is about having a plan in place.

If you are unsure about your health, visit a clinic in Cebu before booking any liveaboards. This ensures you do not waste money on a trip you cannot complete.

Frequently asked questions

Can I dive if I have asthma?

Yes, if it is well-controlled. You should show a doctor that your peak flow is stable and you have no symptoms during daily activity.

Does Type 1 diabetes stop me from diving?

Not necessarily. You need a strict insulin protocol and a doctor's clearance to ensure your blood sugar stays stable at depth.

What is a PFO?

A Patent Foramen Ovale is a small hole in the heart that can increase decompression sickness risk if you dive frequently.