5 Things You Shouldn’t Do After Scuba Diving

Understanding Off-Gassing

Before getting into what to avoid, it helps to understand why any of this matters.

When you breathe compressed air at depth, your body absorbs nitrogen at a rate determined by the pressure around you. The deeper you go and the longer you stay, the more nitrogen accumulates in your tissues. When you ascend, that nitrogen needs to leave your body gradually, released through your lungs as you breathe at the surface.

This process, called "off-gassing", continues long after you exit the water. If you do something that either speeds up nitrogen movement through your tissues or reduces the ambient pressure around your body before that process is complete, you increase the risk of nitrogen forming bubbles in your tissues or bloodstream. These bubbles are what cause decompression sickness (DCS aka the "bends"), and it can range from joint pain and skin rash to neurological symptoms serious enough to require hyperbaric oxygen treatment.

Approximately 90 percent of patients with DCS develop symptoms within three hours of surfacing, though a small percentage become symptomatic more than 24 hours after diving. That window is why the hours after a dive deserve the same attention as the dive itself.

1. Flying Too Soon

This is the most widely known post-dive restriction. Commercial aircraft cabins are generally pressurized to the equivalent of approximately 6,000 to 8,000 feet above sea level. Divers should wait 12-24 hours before any altitude exposures above 2,000 feet, which includes commercial aircraft travel.

For recreational divers, the recommended minimum time to wait before flying is 12 hours following a single dive, and 18-24 hours after multiple dives or multiple days of diving. Many dive computers track this and display a flying-safe countdown, but the timer is a minimum, and conservative divers routinely wait at least 24 hours, especially after multi-day dive trips.

Why do you need to wait before flying? A pressurized cabin at altitude creates a lower-pressure environment than sea level. If nitrogen is still dissolving out of your tissues when that pressure drops, the process accelerates and can form bubbles in your tissues or bloodstream, causing decompression sickness. Waiting gives your body the time it needs to complete off-gassing at sea level.

If you are planning to fly home after diving on the Big Island, build that window into your itinerary before you arrive rather than trying to manage it at the last minute.

2. Driving to Elevation on the Big Island

This is the one that catches visitors off guard, and it is worth giving extra attention if you are diving here.

Decompression sickness resulting from driving or hiking to high elevations after diving should also be considered. The same physics that make flying risky apply to any situation where ambient pressure drops significantly, including a drive up a mountain road.

On the Big Island, this is not a hypothetical concern. Mauna Kea rises to 13,803 feet above sea level, and the Visitor Information Station alone sits at 9,200 feet. Hawaii Volcanoes National Park extends from sea level to 13,680 feet. Both are popular day trips, both are within easy driving distance of the Kohala Coast, and both involve rapid elevation gain.

Another risk that is even less well known is driving the Saddle Road to Hilo. This road reaches an elevation of 6,632, which is too high to drive immediately after diving. There are many roads on the Big Island that go up to elevation quickly, it is a good idea to check road elevations before driving anywhere after diving to make sure you stay safe.

We recommend scheduling your high-elevation activities at the start of your trip, before you start diving. After your last dive, keep yourself at sea level for at least 18 to 24 hours before heading to any significant elevation. If your itinerary has you diving on most days, save Mauna Kea and Volcanoes for a non-dive day.

3. Heavy Alcohol Consumption

A cold drink after a dive is one of the pleasures of the sport, but heavy drinking after diving introduces genuine risks.

Individual factors that can increase a person's DCS risk include dehydration and recent alcohol consumption. Alcohol contributes to both problems simultaneously. It dehydrates you directly, and it can mask early symptoms of DCS that you would otherwise notice and act on.

The symptoms of decompression sickness can be subtle in the early stages. Joint aches, fatigue, tingling, mild dizziness. These are also symptoms that someone who has been drinking might attribute to the alcohol or to a long day in the sun. That confusion can delay seeking treatment, and with DCS, time matters.

Staying well hydrated is one of the most important things you can do after diving to support safe off-gassing. Alcohol works directly against that. If you want to celebrate a great dive, do it with food and water first. A drink later in the evening, after you have rehydrated and eaten a proper meal, carries much less risk than drinking heavily in the immediate hours after surfacing.

4. Hot Tubs and Very Hot Water

The Kohala Coast resort pools are beautiful, and after a day on the water it is easy to understand the appeal of a long soak. But hot tubs specifically, and very hot water generally, are worth avoiding in the hours following a dive.

Hot tubs, saunas, and very hot baths should be avoided after diving. The reason is that heat increases circulation and vasodilation, which can accelerate nitrogen movement through your tissues faster than your body can safely eliminate it. In practical terms, this raises the likelihood of bubble formation in the window when your tissues are still off-gassing.

A lukewarm shower is completely fine. What you want to avoid is the sustained heat of a hot tub or sauna, particularly on a day with multiple dives or deep dives where your nitrogen load is higher. Give yourself a few hours at minimum, and be especially conservative if you have done back-to-back dives or a longer-than-usual bottom time.

5. Intense Physical Exertion

Heavy exercise after diving is less commonly discussed than the other items on this list, but the reasoning is consistent with everything above.

Intense physical activity increases circulation dramatically, which moves nitrogen through your tissues more rapidly. It also generates heat and contributes to dehydration through sweating, both of which compound the risk. And vigorous exercise can make it harder to notice subtle early symptoms of DCS because the physical sensations of a hard workout overlap with early warning signs.

This does not mean you need to spend the afternoon on the couch. A walk, light stretching, or easy activity is fine. What to avoid after a dive day is the hard run, the intense gym session, or any activity that gets your heart rate significantly elevated. Save the physical exertion for a morning before you dive, not the hours after.

One Thing You Should Do: Hydrate

Every item on this list connects back to the same underlying principle: give your body the stable conditions it needs to off-gas nitrogen safely. Staying well hydrated after diving supports that process directly.

Dehydration is one of the consistent individual factors that increase DCS risk. Diving itself contributes to dehydration through immersion diuresis, the physiological response that makes you need to urinate in cold water. Add sun, wind, and salt spray on a boat, and many divers finish a charter already behind on fluids without realizing it.

Drink water consistently after your dives. Eat a real meal. Rest. These are not complicated interventions, they are the baseline conditions that allow your body to do what it is already trying to do.