Starting with the deepest depth and ending at the shallowest keeps Open Water Diver plans safer.

In what order should a diver plan their dives if they are 45', 80', and 62'?

• A. 62', 45', 80'
• B. 45', 62', 80'
• C. 80', 62', 45'
• D. 45', 80', 62'

Answer: (C)

When planning dives, it is crucial to consider depth to manage exposure to nitrogen and avoid potential decompression sickness. The safe practice, often mentioned in diving training, is to dive deep first and then progressively move to shallower depths. This method allows the body to off-gas nitrogen safely as it ascends. In the context of the specified depths, beginning with the deepest dive at 80 feet is appropriate, followed by the dive at 62 feet, and then concluding with the shallowest dive at 45 feet. This sequence minimizes nitrogen build-up and aligns with the physiological principles of diving, ensuring that the diver has sufficient time to off-gas nitrogen absorbed at greater depths before the next dive, which is at a reduced depth. The other sequences do not follow this ascending order. For example, starting with the 62 or 45 feet dives first could lead to an increased risk of nitrogen retention if a deeper dive follows, which compromises the safety of the dive plan. Thus, prioritizing the deeper dive first and moving shallower is the recommended approach for dive planning.

Three stops, one smart order: why the deepest dive comes first

If you’ve ever planned a few dives in one day, you know the clock isn’t the only thing you’re watching. Depth, time, and how your body handles nitrogen all come into play. On a day with three planned depths—80', 62', and 45'—the safest and most common sequence is to start with the deepest, then move to the middle, and finish with the shallowest: 80', then 62', then 45'. Translation: deeper first, shallower last. It’s not just a rule of thumb; it’s about letting your body off-gas nitrogen gradually as you ascend.

Let me explain what’s going on beneath the surface.

Nitrogen and the body: what matters when you pressurize and decompress

When you go underwater, your body absorbs nitrogen from the breathing mix. The deeper you go, the more nitrogen dissolves into your tissues. It’s a little like how sugar dissolves faster in hot water—the deeper the pressure, the more nitrogen gets into solution. That nitrogen sits there, like a save file in a game, waiting for the right moment to come out.

As you ascend, pressure drops and nitrogen starts to come back out of solution. If you climb too quickly, or if you string together too many deep dives without enough time at shallower depths to vent that nitrogen, you risk forming bubbles. And those bubbles are what can lead to decompression sickness, or DCS. This is not something to bluff about; it’s a real safety concern that divers train to avoid.

The practical takeaway: deep dives load you up with nitrogen, and shallow dives on the same day help you vent it gradually. Think of it as a controlled exhale after a deep inhale—you want the process to unfold calmly, not in a rush.

The specific sequence: 80', then 62', then 45'

Let’s walk through the three depths you mentioned. You descend to 80' first. This is the deepest of the three, so it carries the heaviest nitrogen load. By starting here, you’re facing the greatest pressure and the greatest initial nitrogen uptake while you’re fresh and alert. After the dive, you surface, breathe normally, and—if your plan calls for a second dive on the same day—you wait long enough to let some off-gassing begin. Then you move to 62'. This is shallower, so the pressure is less, and your body has more opportunity to vent nitrogen that built up during the 80' dive. Finally, you finish at 45', the shallowest of the trio. At this depth, the risk from new nitrogen loading is minimal compared to the earlier dives, and any remaining off-gassing can continue as you complete your plan and head back to air on the surface.

Why not start with 62' or 45' first?

If you began with a shallower depth and then chased a deeper dive later in the day, you’d be stacking depth and nitrogen load in a way that makes off-gassing more challenging. The nitrogen that your body absorbed during the deeper dive has to be released as you rise, not the other way around. If you intentionally or unintentionally force a deeper dive after a shallower one, you’re asking your body to work through more complex off-gassing patterns in a shorter window. In short: deeper first helps your tissues vent nitrogen in a more predictable, safer sequence.

A little context that helps visualization

Imagine you’ve got a glass of soda with a cap on. You shake it to mix more gas into solution (that’s your deep dive loading). Then you slowly uncap the bottle and let some gas escape as you return it to a calmer state (your ascent and shallower dives). If you try to shake a fresh bottle after it’s already releasing gas, you risk fizzing over the top. In diving terms, the “fizzing over” is the nitrogen coming out too quickly, which can lead to bubbles that you don’t want.

Practical planning tips that keep the sequence safe

• Use your tools. A reliable dive computer or follow a trusted set of dive tables helps you stay within no-decompression limits. These tools aren’t there to spoil the fun; they’re there to give you feedback on how much nitrogen you’re carrying and when you’re safe to ascend.

• Allow for a surface interval. Between dives, give yourself a breathing room. A few minutes at the surface isn’t just resting; it’s your chance to shed some of the nitrogen your tissues still hold after the deeper dive.

• Stay hydrated and rested. Your body handles gas exchange best when you’re not fighting dehydration or fatigue. It sounds simple, but it matters.

• Keep track of time in the water. The longer you stay at depth, the more nitrogen you’ll absorb. Shorter bottom times at each depth, especially the deeper one, help you stay within safe margins for the day.

• Plan the order before you gear up. If you’re the kind of diver who likes to wing it, you’ll end up improvising under pressure. A quick plan, agreed upon with your buddy, keeps the team aligned and reduces risk.

• Include a safety stop as a habit. Even when you’re not required to decompress, a brief stop around 15 feet for 3 minutes gives your body a final chance to off-gas before you finish up.

Relatable analogies and a touch of realism

Let’s leave the lab talk for a moment and connect it to everyday life. You wouldn’t rush to run a marathon after a long hike without a breather, right? Your lungs and muscles don’t suddenly forget how to function after a hard effort; they just need a moment to settle. Diving has a similar rhythm, only with your tissues and nitrogen as the players.

Or think of it this way: if you mix too many tasks at once, you lose track of one thing and miss a beat. The sea rewards patience. The numbers on your computer aren’t just digits; they’re a safety net. They’re telling you when your body’s ready for the next step, and when it’s not.

Common sense checks that keep you honest

• If you feel unusually tired, cold, or have joint aches after a dive, tell someone and reassess. These can be warning signs, and it’s better to check than to shrug it off.

• Don’t skip the surface interval for the sake of finishing a plan. A longer surface break can help you avoid pushing your body toward a risky sequence.

• Buddy checks aren’t only a formality. They’re a lifeline. Agree on the plan, confirm each depth and time, and keep communication open throughout the day.

What this means for real-world dives

When you’re lining up a three-stop day with depths like 80', 62', and 45', you’re not just checking boxes. You’re shaping how your body handles gas exchange, how well you’ll sleep after the day, and how safe you’ll feel as you float on the surface afterward. The deepest dive first is a straightforward rule that makes sense once you see nitrogen as a guest who prefers a calm exit. If you start deep, then intermediate, then shallow, you’re giving yourself the clearest path to off-gassing and a comfortable recovery.

A quick recap to keep handy

• The safe order for those depths is 80', 62', 45'.

• Deepest dive first means your body handles the heavier nitrogen load at the outset.

• Shallower dives after the deepest one let off-gas occur more gradually as you ascend.

• If you reverse the order, you increase the complexity of off-gassing and raise the risk.

• Rely on your dive computer or dive tables to stay within no-decompression limits, and don’t skip the surface interval.

• Stay mindful of how you feel, communicate with your buddy, and keep safety stops in the plan.

If you’re curious about how this plays out day-to-day, joining a small group or a guided dive can be a great way to see the theory in action. You’ll notice the tempo of the day changes once everyone buys into the deep-then-shallow rhythm. It isn’t about rigidity; it’s about predictable safety, paired with the thrill of exploring new depths.

A final thought

Diving is a dance between ambition and caution. The deepest step first is a simple rhythm that respects your body’s needs while letting you enjoy the moment beneath the waves. The ocean isn’t going anywhere, but your safety is never guaranteed unless you plan with intention. So next time you map out a three-stop day with depths like 80', 62', and 45', remember that the right order isn’t just a rule—it’s a practical approach that keeps you in the green zone where your curiosity can safely lead the way.