Know when to skip going into the water: illness, fatigue, or substances can ruin a session

When should you avoid diving?

• A. You should avoid diving if you are ill, fatigued, or have consumed alcohol or drugs
• B. You should always dive regardless of your condition
• C. Diving is only unsafe when there is a storm
• D. You can dive if you are slightly fatigued

Answer: (A)

The recommendation to avoid diving when you are ill, fatigued, or have consumed alcohol or drugs is essential for ensuring safety underwater. Diving requires physical and mental alertness; any impairment—whether due to a medical condition, tiredness, or substances—can significantly affect a diver's ability to respond to emergencies, follow procedures, and communicate effectively while diving. Being ill can impair your ability to equalize pressure in your ears or may lead to further medical complications while underwater. Fatigue can decrease your concentration and reaction times, which are critical for safe diving practices. The consumption of alcohol or drugs can alter your judgment and impair physical coordination, both of which are dangerous when engaging in activities that require precise physical skills and cognitive functions. Therefore, avoiding situations that compromise your health or safety, such as the ones mentioned, is a fundamental aspect of responsible diving practices, emphasizing the importance of being physically and mentally prepared before diving.

Open Water, and the rule that keeps you afloat in more ways than one

Ever felt the pull to head out on a sunny day, even when you’re not feeling 100%? Maybe you stayed up late, caught a cold, or had a couple drinks the night before. It happens to the best of us. Here’s a simple, rock-solid rule you’ll hear echoed in IANTD’s Open Water program and in real-world safety conversations: you should hold off on going under when you’re ill, fatigued, or have consumed alcohol or drugs. The short version is A.

Let me explain why that rule isn’t about being overly cautious; it’s about keeping you safe and in control when things can change in a heartbeat underwater. The water doesn’t care about good intentions. Pressure changes, currents, and equipment handling demand sharp thinking, precise timing, and steady coordination. If any part of you is off—whether you’re sick, tired, or under the influence—your ability to respond to a problem can slip, sometimes in ways you don’t notice until it’s too late.

Illness: a snag in your balance and your ears

When you’re ill, your ears and sinuses can behave unpredictably. Equalizing pressure is a core skill in any underwater session, and it relies on a clear head, good breathing, and some physical resilience. Illness can also bring congestion, fever, or dehydration, all of which complicate the whole process. If you’re congested, that fullness can turn a routine pressure change into a painful squeeze. If you’re feverish, your body is already fighting a battle you can’t see, and adding a submerged task to that mix isn’t fair to you—or to your buddy.

Fatigue: when your reflexes are on pause

Fatigue is a stealthy enemy. It doesn’t shout; it whispers, then it quietly slows your reactions. In the water, split-second decisions matter: timing a buoyancy adjustment, recognizing a signal from your buddy, or recognizing when a current is nudging you off course. A tired body may still function, but it won’t function as crisply as it needs to when you’re handling gear, managing buoyancy, and monitoring your gas supply all at once. Even a slightly foggy mind can turn a routine ascent into a challenge. That’s why fatigue is a real-deal red flag.

Alcohol and drugs: judgment under pressure is a fragile thing

Alcohol and drugs don’t merely dull your senses; they skew your risk assessment. They can slow your movements, blur your depth perception, and cloud your ability to communicate clearly with a buddy. In an environment where miscommunication or slow reactions can cascade into a serious situation, that’s a combination you want to avoid completely. The math is simple: impairment plus unpredictable water conditions rarely adds up to a safe outing.

This isn’t about fearmongering; it’s about honoring the limits of the body and the realities of underwater environments. The goal is to be prepared, not to push through. If you’re feeling off in any of these ways, you’re better off postponing and choosing a path that keeps you in good shape for the next opportunity.

A quick, practical check you can use before any water outing

Think of this as a mental checklist you can run through in the minutes before you head to the water’s edge. It’s not a complicated test; it’s a practical gut-check to protect you and your buddy.

• Am I feeling well, without fever, severe congestion, or persistent cough that affects breathing?

• Did I sleep solidly last night, with enough energy to focus and move deliberately?

• Have I avoided alcohol and any substances that could impair my judgment in the last 24 hours?

• Is there any new medication or over-the-counter medicine that could affect my alertness or breathing?

• Do I feel steady on my feet, not just physically but mentally, with a clear sense of how I’ll handle emergencies?

If the answer to any of these is “not quite,” consider staying on shore or choosing a lighter, non-submerged activity. It’s a tiny decision with big upside: you keep your skills sharp and your confidence intact for the next time you head out.

What to do instead when you’re not feeling 100%

You don’t have to skip every adventure just because you feel a little off. You can still stay connected to the water and keep learning. Here are some lighter, safer alternatives that keep you connected to the water world without compromising safety:

• Shore-based skills review: go over buoyancy control, mask clearing, and regulator recovery on land with the same calm, deliberate focus you’d bring to the water. The muscle memory you build on land translates nicely underwater when you’re ready.

• Dry-land fitness and flexibility: a short routine can help your body perform better in the water later. Think breathing exercises, light stretching, and core movements that won’t tire you out but will improve control and stamina.

• Gear familiarity on the surface: check your equipment, practice proper assembly and disassembly, and review signal communication with your buddy while you’re both comfortable on the surface. Everything you learn to do smoothly when you’re fresh pays off when you’re in the water.

Note that some people find it helpful to log a few buoyancy and regulator checks in calm, shallow water when they’re starting to feel a bit tired or congested. It’s not about forcing the activity; it’s about maintaining a bridge to the underwater world while you recover.

A few real-world reminders that stick

• Illness can creep up fast. A cold can turn into a bigger issue under pressure. If you’re feeling off, the safer choice is to wait. A single day’s delay is a small price for long-term safety.

• Fatigue isn’t a badge of perseverance; it’s a signal. If you’re yawning during your equipment check, that’s your body telling you to pause.

• Substances don’t mix well with precision tasks. Even when you think you’re handling things—that steady rhythm you rely on can slip.

Those little moments of pause are not about preventing fun; they’re about keeping the experience enjoyable in the long run. When you return to the water after rest and recovery, you’ll notice your signaling becomes clearer, your buoyancy steadier, and your confidence higher.

Bringing it back to the big picture

This simple rule—avoid going under if you’re ill, fatigued, or have used alcohol or drugs—fits into a broader safety philosophy that you’ll encounter in the IANTD Open Water program. It’s not a rigid checklist meant to quarantine joy; it’s a framework that helps you make smart, informed decisions. Underwater environments demand discipline, not bravado. A well-timed pause now can prevent a handful of headaches later.

If you’re thinking about the kind of person who makes a good safety partner, this is a cornerstone: you look after yourself so you can look after your buddy. Clear communication, honest self-assessment, and a shared commitment to safety are the backbone of any successful underwater outing. The moment you protect your own health and alertness, you also protect the people who rely on you the most: your team.

The habits that matter most

• Always err on the side of caution. If there’s any doubt about your condition, choose to stay ashore or to postpone the submerged portion.

• Build a ritual around pre-outing checks. A quick but thorough surface check is faster than dealing with a mishap later.

• Keep the conversation open with your buddy. A simple “Are you okay to proceed?” can avert misunderstandings and keep pace with safety.

• Treat every outing as a learning moment. Even when you’re feeling great, notice what went well and what could be improved next time. Small improvements compound.

A closing thought

The ocean—whether you call it the sea or the open water—has a way of humbling you. It doesn’t care about your schedule, your plans, or your enthusiasm. It cares about safety, preparation, and awareness. The guidance you’ll encounter in the Open Water program emphasizes that health and clarity aren’t afterthoughts; they’re the first gear you put on before you even consider entering the water. That gear—your own body and mind—deserves care.

If you’re drawn to the idea of a submerged adventure, make sure you bring with you a reliable rulebook in your head and in your checklist. The rule to skip the activity when you’re unwell, tired, or under the influence isn’t a barrier to experience; it’s a guardian that keeps the voyage enjoyable and the memories positive. After all, the best stories from the water aren’t about how hard you pushed through; they’re about how smart you were in the moment and how calmly you handled the next step when you were ready.

So the next time you’re considering a water outing, ask yourself the same simple question: am I in good shape to go, in body and mind? If the answer isn’t a confident yes, you already know what to do. Wait, regroup, and savour the anticipation of your next underwater journey—one that’s safer, calmer, and closer to the edge of what you love, not beyond your limits.