Managing Cold, Heat, and Dehydration Post-Dive

Getting cold, overheating, or getting dehydrated might not sound like emergencies—but in diving, they often are. These environmental stressors reduce your ability to think clearly, increase your risk of decompression sickness (DCS), and make accidents more likely.

This page covers how to recognize early signs of trouble, how to respond quickly at the surface, and why surface support matters just as much as bottom time.

Why This Matters

Environmental stress affects everything from your awareness to your physical response time. When a diver is cold, dehydrated, or overheated:

• Their ability to think clearly drops
• Their reaction time slows
• Their decision-making gets worse
• Their risk of DCS goes up
• They're more likely to panic or miss key signals

These aren’t just comfort issues—they’re safety issues.

Cold Exposure After the Dive

Even in warm water, divers often get cold after long dives. Wind, evaporation, and inactivity during surface intervals make it worse.

Watch for:

• Shivering or teeth chattering
• Cold, pale, or bluish skin
• Sluggish speech or movement
• Difficulty focusing or staying alert

What to Do:

• Get the diver out of wet exposure gear
• Dry them off completely
• Provide dry clothes or a towel and warm hat
• Give warm (not hot) fluids like tea or broth
• Use an emergency blanket or warm car if needed
• Postpone the next dive if symptoms persist

Personal Note: I bring a Surfur coat on most of my local dives. It’s been loaned out more than once to shivering open water students who showed up with only a towel and a hoodie.

Tip: Even mild hypothermia can lead to poor gas tracking, bad ascent timing, or missed buddy signals. Don’t rush back in.

Heat Stress and Overheating

This mostly affects divers in hot climates or when wearing thick gear on land (like drysuits or 7mm wetsuits).

Watch for:

• Flushed skin, nausea, headache
• Heavy sweating, then no sweating
• Dizziness, disorientation, or irritability
• Rapid breathing or heart rate

What to Do:

• Move the diver into shade or an air-conditioned space
• Remove exposure suit and outer layers
• Cool with water, fans, or cooling towels
• Offer small sips of cool water
• If symptoms worsen or don’t improve, call EMS

Important: Heat exhaustion can progress to heat stroke—don’t ignore it just because the diver “feels fine.”

Dehydration: The Overlooked Risk Factor

Diving itself accelerates dehydration. Immersion diuresis (peeing from cold water immersion), sweating in exposure suits, and limited fluid intake all contribute.

Important: Hydrate before diving. Don’t skip fluids just to avoid peeing in your wetsuit. That kind of decision might feel polite—but it’s dangerous.

Find a routine that works for you.
I use sports drink powders like Skratch to add salt and carbs before diving, then switch to another drink after the dive to rehydrate. I also tend to get cramps pretty frequently, so I’ve had to learn how to prepare for them, adjust my dive plans, and let my buddies know ahead of time. Whether you use electrolyte mixes, salty snacks, or a specific pre-dive drink—build a system that works for your body and dive conditions.

Watch for:

• Dry mouth, dizziness, headache
• Low urine output or dark yellow urine
• General fatigue or irritability

What to Do:

• Encourage water between dives—aim for small sips, often
• Avoid alcohol, energy drinks, and excessive caffeine
• Bring electrolyte tabs or mixes in your surface kit
• Track fluid intake as part of your dive prep—not just food or gear

Build a Support-Ready Surface Kit

Just like you carry emergency medical supplies, your kit should include basic environmental recovery tools:

• Large towels or warm ponchos
• Emergency blankets
• Cooling towels or water sprayers
• Shade structure or pop-up canopy
• Rehydration tabs or electrolyte mixes
• Insulated bottles with cool or warm liquids
• Dry clothing layers and hats

These don’t need to be expensive—but they need to be present. Keep them in your surface bin or dive bag, and check restock between trips.

When to Call the Dive

Environmental stress doesn’t fix itself underwater. If a diver shows any sign of heat illness, hypothermia, or dehydration that isn’t resolved before the next dive: Call the dive.

No piece of gear or logbook entry is worth pushing through discomfort that compromises safety or cognition.