Safety is a huge part of scuba diving; Following No Decompression Limits, ascending slowly, staying close to your buddy, and checking air consumption regularly. But the safety does not end when you are back on the boat. There are a few things to keep in mind in the hours after a scuba dive, in order to stay safe and healthy.
As scuba divers learn in their courses, we accumulate nitrogen when we dive. The deeper you dive, the more nitrogen our bodies take on. We ascend slowly and do our safety stops to give that nitrogen time to “off-gas” while we are still under the water. Ascending too quickly, or skipping safety stops may result in the nitrogen forming little bubbles in the blood, and this is what causes decompression sickness.
Some divers, however, are unaware that this nitrogen is still off-gassing in the hours after a dive. So it is important to avoid a few things after diving, in order to off-gas safely and successfully.
1. Going to high altitudes
If you have taken a scuba diving course, you will no doubt have been told about this important rule: Do not fly after diving!
The general rule for flying after diving is to wait 12 hours after one dive, and 18 hours after two or more dives. If you went over your no decompression limits, or missed a safety stop on the dive, it is advised to wait 24 hours.
This is because when we go up in an airplane, the altitude increases, so the air pressure is lower than it is at sea level. This can encourage the nitrogen you have accumulated on the dive to expand too quickly (a similar effect to ascending too fast) and this is what causes decompression sickness.
It is also advised to avoid going up mountains that are higher than 1,000ft (300m) for 24 hours after diving. For the same reasons as flying; The altitude is higher than at sea level, which creates an increased difference in pressure between your surroundings and the nitrogen in your body from the dive. The nitrogen expands too quickly and decompression sickness becomes a risk.
It is important to consider these risks when planning your vacation itinerary: Do not dive on your last day, and do not climb any mountains after a dive.
Learn all important things you need to know about decompression diving: SSI Decompression Diving – All You Need To Know (divessi.com)
2. Freediving
Freediving is another great way that ocean-lovers can explore the reef. But did you know that it can be dangerous to freedive after a scuba dive?
It can be tempting after the thrill of an exciting scuba dive to jump straight back in the water with your mask and fins to see a little more. Perhaps there is a manta ray circling the boat… of course you want to dive in and see! But it is best to stay on the surface and avoid holding your breath and diving down.
This is because there is still nitrogen in your body from the scuba dive. Going back to depth and ascending fast could affect the nitrogen off-gassing, and as we know, this is what triggers decompression sickness.
Scuba divers generally follow the same rules for freediving as for flying: Wait 12 hours after one dive, and 18 hours after two or more.
Play it safe, snorkel at the surface instead.
Learn to Freedive: 9 Reasons Why Freediving is the Perfect Hobby (divessi.com)
3. Hot water
Who does not love a nice, hot bubble bath? Especially when you are chilly after some cold water diving! But you might want to wait before turning the taps on.
As tempting as it is to try to warm up fast in a hot shower or bath, when your body gets submerged in hot water, your tissues get warm. This can promote the formation of nitrogen bubbles in the blood, and these bubbles are what cause decompression sickness. A gas’s solubility is related to temperature. For example, when you see boiling water, bubbles appear when the water gets to a hot enough temperature.
There’s no set rules, but DAN (Divers Alert Network) recommends that you wait between five to 30 minutes after a dive before having a hot shower or bath, or before getting into a hot tub. It is also suggest that if you really can’t wait to rinse off, try to dive more conservatively (shallower and well within No Decompression Limits) to reduce the amount of nitrogen left over in your body after the dive, and have a luke-warm shower or bath, rather than a very hot one.
4. Massage
There is nothing more relaxing than a massage, the perfect way to wind down on vacation. But, you might want to avoid booking a deep tissue massage for after a scuba dive.
Although there is not much evidence to support this theory, many people in scuba diving believe that massage might cause bubble formation because it increases the blood flow. Some believe it can also push these bubbles into the joints and cause them to get trapped and cause pain.
There is another reason to avoid massage after diving. Deep tissue massage may cause pain in the tissues and soreness in the muscles. As aches and pains are a symptom of decompression sickness, it may be misconstrued as such and lead to an unnecessary trip to the doctors. Or, you may think that your muscle soreness is simple due to your strong massage, and ignore your symptoms of what is actually decompression sickness. This could result in waiting too long to seek important treatment you might need.
Curling up on the sofa and watching an inspiring ocean documentary is something that is perfectly safe and recommended after a long day of diving!
Signs and symptoms of decompression sickness
Now you know what to avoid after scuba diving to avoid decompression sickness. But would you recognise the signs and symptoms of decompression sickness if you or your dive buddy were struck by it?
Here are the main signs and symptoms to look out for:
- Joint and/or muscle pain or aches
- Tingling, numbness, or pins and needles
- Paralysis
- Skin rash
- Itchy or painful skin
- Fatigue
- Headache
- Confusion
- Impaired vision
- Loss of hearing or ringing in the ears
- Weakness
- Nausea or vomiting
- Coughing up blood
- Uncontrollable shivering
- Unconsciousness
If you experience any of these symptoms, or see the signs in another diver, seek medical assistance quickly, and breathe pure oxygen on the surface, if available.
