Understanding the primary cause of decompression illness and why following decompression tables matters

What is the primary cause of decompression illness?

• A. Not following the decompression tables
• B. Diving with inexperienced buddies
• C. Using faulty equipment
• D. Strong currents during the dive

Answer: (A)

The primary cause of decompression illness is related to not following the decompression tables. When a diver ascends too quickly after spending time at depths where the surrounding pressure is significantly higher than at the surface, nitrogen dissolved in the body can come out of solution too rapidly. This can lead to the formation of nitrogen bubbles in the bloodstream and tissues, which is what causes decompression illness, often referred to as "the bends." Decompression tables provide critical information on how long a diver can safely remain at certain depths and how to ascend properly to avoid these risks. Following these guidelines allows the body to off-gas nitrogen at a safe rate, minimizing the likelihood of illness. While diving with inexperienced buddies, using faulty equipment, and being exposed to strong currents can contribute to unsafe diving conditions, they do not directly cause decompression illness in the same way that improper ascent and failure to adhere to decompression protocols do.

Outline:

• Hook: Decompression illness isn’t flashy, but it’s a real risk we can manage.

• What is decompression illness (DCI) and the role of nitrogen bubbles.

• The primary cause: not following decompression tables. How off-gassing works and why a careful ascent matters.

• The other factors people worry about (inexperienced buddies, faulty gear, strong currents) and why they’re not the direct culprit.

• How divers stay safe: planning, ascent rates, safety stops, and using tables or computers.

• Quick takeaway: answer to the main question and the big picture for everyday diving.

Why this matters more than you might think

Let me explain something simple but powerful: you can control a lot of your safety underwater by respecting a few basic rules. Decompression illness, sometimes called the bends, is not something you want to ignore. It isn’t about who has flashier gear or who can hold their breath the longest. It’s about how your body handles nitrogen after you climb back toward the surface.

What is decompression illness, really?

When you duck beneath the surface, nitrogen from the air dissolves into your blood and tissues because the surrounding pressure is higher than at the surface. That’s a normal part of every dive. The trouble starts when you rise too quickly. If the pressure drops fast, the dissolved nitrogen comes out of solution too quickly and forms tiny bubbles in your bloodstream and tissues. Those bubbles can block small blood vessels, irritate nerves, and cause pain, dizziness, tingling, or worse. It’s the classic “the bends” moment, and it’s exactly why we have decompression tables and careful ascent protocols.

The primary cause: not following the decompression tables

Here’s the thing that matters most: the primary cause of decompression illness is not following the decompression tables. These tables aren’t there to ruin your joy of exploring. They’re a safety system. They tell you how long you can stay at certain depths and, crucially, how you should ascend to let your body off-gas nitrogen at a safe pace. If you ignore those guidelines and head for the surface too quickly after spending time at depth, you increase the chance of forming nitrogen bubbles. And yes, that can happen even on dives that feel perfectly fine at the moment.

Think of it like baking: if you slam the oven door shut too fast or remove the cake from heat too early, you don’t get the right texture. The table is your recipe. It’s not optional fiction. It’s a guideline built from countless dives, experiments, and real-world data. When you follow it, you’re giving your body a chance to return to surface pressure gradually—smoothly, safely.

Why other factors aren’t the direct cause, though they matter

People often worry about a few other elements:

• Inexperienced buddies: Having a buddy who’s new or unsure can raise risk, because you may end up rushing to help or cut corners in ascent. This can tempt you to skip a step or shorten a safety pause. But the buddy itself isn’t the root cause of DCI. The cause is still not following the decompression guidelines.

• Faulty equipment: Leaks or a malfunctioning regulator can spike stress or complicate ascent. Equipment problems can turn a simple dive into a scramble, which might push you toward unsafe decisions. Yet even with gear hiccups, the illness itself comes from an ascent that doesn’t respect off-gassing.

• Strong currents: Currents can push you toward the surface or pull you away from planned stops. They increase the mental and physical load and can tempt you to skip steps. Currents are risk multipliers, not the direct cause of decompression illness.

In other words, those factors elevate risk, but the direct culprit remains improper ascent and neglecting the decompression protocols.

How your dive plan and a table keep you safe

Decompression tables are part of a larger system that includes your plan, your speed, and your awareness of your own body. Here’s how it all connects in practice:

• Plan depth and bottom time: Before you drop, you know how deep you’ll go and how long you’ll stay. This helps you estimate how nitrogen will accumulate in your tissues.

• Follow the ascent schedule: The table guides your rise. It tells you when to pause and for how long at shallow depths. That pause—often called a safety stop—is your buffer against rapid off-gassing.

• Use the right tool for the job: Some divers rely on tables; others use dive computers. Both aim to keep your ascent within safe limits. A computer can adjust in real time if you drift or stay a touch longer at depth, but it still expects you to stay within the core principles: plan, monitor, ascend slowly, stop, and breathe easy.

• Stay within your limits: Your personal health, fatigue, cold, dehydration, and other factors all influence how nitrogen behaves in your body. If you’re tired or not feeling well, it’s wise to rethink a planned ascent rate or even skip a dive.

Let’s make this practical for everyday diving

If you’re just getting started with IANTD Open Water Diver training, here are some down-to-earth moves that keep you on the right track without turning you into a robot:

• Plan your dive with intention: Decide depth, duration, and surface intervals before you enter the water. A good plan is a calm mind.

• Move slowly upward: Ascend no faster than the pace recommended by your table or computer. If you’re unsure, err on the side of a slower ascent.

• Stop at the right depth: A brief safety stop at around five meters for several minutes is common practice. That pause is a simple habit with big payoff.

• Monitor your body: If you feel numbness, tingling, joint pain, dizziness, or extreme fatigue after a dive, seek help. Do not ignore warning signs.

• Buddy system, thoughtfully: Dive with a partner who shares your commitment to safety, not just someone who looks good in photos. Communicate plans, check equipment, and stay together during ascent.

• Rely on solid gear, but don’t worship it: Keep your gear in good shape, test it before the dive, and don’t rely on gear alone to save you. Skills and discipline carry more weight than fancy gadgets.

A quick, honest takeaway

Here’s the bottom line: decompression illness happens when your body can’t off-gas nitrogen at a safe rate, and the primary driver is not following decompression tables. The other factors—bad buddy choices, equipment hiccups, and strong currents—make dives feel harder and riskier, but they don’t directly cause DCI in the same way. Respect the plan, and your body, and you’ll keep things smooth and enjoyable.

A tiny Q&A to wrap things up

Question: What’s the main reason people end up with decompression illness?

Answer: Not following the decompression tables. The tables give your body the roadmap to off-gas nitrogen safely as you ascend.

If you’re curious about how the numbers translate into real-world dives, talk with your instructor or a seasoned buddy. They can walk you through example dives, show you how to read your computer or tables, and help you feel confident in your own ascent rate and safety stops. It’s not just about checking boxes; it’s about building a mindset of careful planning and patient ascent.

Finally, the thrill of the ocean is real. The quiet wonder you feel watching a reef or a school of fish can be amplified when you know you’re following a safe path back to the surface. DCI is preventable, and the path to prevention isn’t mysterious. It’s discipline, planning, and respect for the rhythm of the water.

Key takeaways you can carry with you:

• The primary cause of decompression illness is not following decompression tables or proper ascent guidelines.

• Nitrogen off-gassing is the science behind DCI; the pace of your ascent matters a lot.

• Inexperienced buddies, faulty gear, and currents can introduce risk, but they aren’t the direct cause of DCI.

• Plan dives, ascend slowly, and perform safety stops. Use tables or computers wisely, and stay attuned to how you feel.

• Stay curious, keep learning, and dive with partners who value safety as much as the thrill of discovery.

If you keep these ideas in mind, you’ll not only pass the essential milestones of your training but also carry a deep respect for the ocean’s timing and rhythm. And that respect—paired with good technique—will help you stay safe while you uncover the underwater world’s many quiet wonders.