By Mario Medarevic
Published on DiveWorld.ca
Decompression sickness (DCS) is often viewed as something that happens only to technical divers pushing deep limits. But that’s a dangerous misconception.
DCS is a probabilistic condition — meaning it can affect any diver, even on what appear to be “safe,” no-decompression dives.
At DiveWorld, we’ve seen it happen firsthand: recreational divers presenting with DCS symptoms after routine dives well within their computer’s limits.
So what gives? And how can you stack the odds in your favor?
Let’s break down what we know, what we still don’t, and the five most effective strategies I teach all divers to reduce their DCS risk.
Decompression sickness occurs when nitrogen, absorbed under pressure, forms bubbles in your body during or after ascent. While your dive computer tracks the two main variables — depth and time — actual DCS risk is influenced by a broad spectrum of other factors, such as:
Water temperature
Physical exertion
Dive profile shape
Breathing gas
Hydration
Fitness and fatigue
Age and body composition
Circulatory health
Acclimatization
Modern decompression algorithms do an impressive job estimating inert gas load, but they’re still mathematical models, not foolproof systems. They’re not based on clinical trials with DCS symptoms as the endpoint.
That’s why getting close to your no-decompression limit (NDL) — even if you technically stay “within” it — still carries elevated risk.
Today’s dive computers use multi-level profiles to dynamically adjust NDLs, allowing for longer bottom times than traditional dive tables ever permitted.
But more time at depth means more inert gas loading.
Some divers treat NDLs like a red line — “if I don’t cross it, I’m fine.” In reality, DCS risk increases gradually the closer you get to that line.
Staying within 50% of your NDL offers dramatically reduced risk — especially when combined with good diving practices.
These are the five strategies I personally follow and teach to every diver, no matter their experience level. They’re simple, effective, and make a measurable difference in safety.
Don’t leave your settings on “default.” Use the most conservative algorithm or gradient factor available — especially in cold water or during repetitive dives.
This increases your safety buffer and can be adjusted on most modern computers.
If your NDL is 20 minutes, plan to ascend by 10. Don’t push the limits just because your computer allows it.
Reducing your exposure time cuts your decompression stress significantly — and still gives you a solid dive.
Fatigue, illness, and alcohol impair off-gassing and decision-making.
If your body isn’t at 100%, don’t dive. It’s not just a matter of performance — it’s a matter of safety.
Cold exposure limits circulation and slows nitrogen elimination.
Wear appropriate exposure protection and stay warm during your ascent and safety stop — this is when efficient off-gassing matters most.
Short surface intervals don’t give your body time to off-gas residual nitrogen.
Aim for at least two hours between dives whenever possible. It’s one of the easiest and most effective ways to minimize cumulative DCS risk.
Dive computers are excellent tools — but they don’t eliminate risk. They only estimate your nitrogen load using simplified models.
The best approach?
Use the tech, but add margin.
Dive with intention, not just by numbers.
Respect your body, your conditions, and your exposure. The divers who stay healthy are the ones who play the long game — not the ones chasing bottom time dive after dive.
Stay smart. Stay safe.
See you in the water,
Mario Medarevic
Instructor | DiveWorld.ca
Questions? Call us at 416-503-3483 and speak to an experienced professional.