A Critical Look at No-Decompression Limits

As a hyperbaric physician and dive instructor, I’ve been around a lot of dive accidents, and I’ve spent decades educating divers and treating decompression sickness (DCS). A misunderstanding I consistently see among the divers I treat pertains to no-decompression limits (NDLs), with divers repeating the common refrain that they were “diving within the limits” and that their DCS must therefore have been a random event.

dive computer

Checklists

Checklists may be the missing tool to safer diving. Checklists are used in other fields, not just diving, like aviation and surgery. Read more about the history and importance of checklists.

Male diver is sitting down and hand with checklist is in foreground

To Lie or Not to Lie?

When signing in for a dive, the medical statement can feel both burdensome and an invasion of privacy. You may want to lie. However, medical statements are an important element of dive safety.

Perspective diver prepares to fill out medical statements and cartoony devil and angel are on his shoulders

Questions To Ask a New Dive Buddy 

You check in at the dive shop, sign your waivers, get your gear on the boat, and set up your BCD on your first tank for the day. The divemaster introduces you to your dive buddy for this trip — a total stranger from another part of the world who is here for the same things you are: great diving and returning home safely. 

Divers communicate with each other

More Than Just Bubbles

While prevention against decompression sickness, it’s relatively rare. Comparatively, there are more common hazards to divers. Read more.

Paramedics tend to a cyclist with a head injury

Shallow-Water Arterial Gas Embolisms

Pulmonary barotrauma can occur in a shallow swimming pool if a diver holds their breath during ascent or inadvertently floats to the surface while holding their breath. Most dive-related pulmonary barotraumas occur in compressed-gas diving due to pulmonary overinflation during a breath-hold ascent. Pulmonary barotrauma can occur even with normal breathing if there is an obstruction in the bronchial tree that prevents one lung segment’s normal ventilation.

Even in shallow water and while preoccupied with other tasks, it is important to breathe continuously. Relax and breathe normally during ascent to help avoid pulmonary barotrauma.

Exercise and Decompression Risk

Being physically fit can be important, and sometimes crucial, for dive safety. Physical fitness plays a role in both regular dive activities and emergent events. A quick and effective response to sudden demands can often quickly and easily resolve a situation, while an insufficient response can prolong or exacerbate it.

man jogging

Lionfish Stings

Lionfish are fascinating and beautiful creatures, but they can cause serious injuries as well as environmental problems outside their normal range.

A melancholy lionfish swims about looking for someone to sting.

Acclimatization

Acclimatization is the adaptation to natural exposure, but could this apply and alter decompression stress? One research team looked at how acclimatization and repeatedly diving could impact someone’s predisposition to decompression sickness.

Diver blows into a tube and other man monitors on laptop

Beware the Mooring Lines

Divers have become more susceptible to stings and other injuries when trying to grasp permanent mooring lines. Learn why this has become a problem and how to manage injuries.

Three divers pause on a mooring line for a stop during their ascent