So you’ve just enjoyed a dive. Exhilarated after your underwater adventure, you kick back and instinctively reach for your packet of cigarettes.
Hold on just a moment though. Is it entirely safe to do so? Can you smoke after scuba diving, or is there a risk of making yourself ill?
Firstly, if you’re concerned about making yourself ill, smoking perhaps isn’t the pastime for you. We’ve all seen the giant warnings and ghastly images emblazoned across cigarette packets. Smoking is directly responsible for a large proportion of deaths among smokers, with various cancers and lung problems chiefly responsible. Beyond that, many other non-fatal health conditions such as glaucoma can be attributed to smoking without many even being necessarily aware.
This is hardly breaking news for smokers however. Everyone is well aware of the health implications of smoking. Many, though, don’t realise the negative effects it can have on scuba divers. Indeed, while there’s little to suggest that smoking a cigarette after diving is any more harmful than it already is, the main danger lies in the damage smoking has done to your body before you hit the water.
How smoking affects your body pre and post-dive
Heart attacks, strokes and blood pressure
When diving, our bodies undergo a physiological change known as the ‘mammalian diving reflex’. This is a natural response that we all experience when going underwater. Essentially, what this means is that our bodies recognise that we’re underwater, and start to increase our blood pressure to focus our blood flow and its oxygen supplies to our hearts and brains.
This stronger flow of blood to the heart can result in some irregularities to heart rhythms, and in some unfortunate cases, heart attacks or strokes. While it’s thankfully relatively rare, every diver’s heart is more at risk underwater simply because of the additional strain put upon it. More than a third of all diving deaths are attributed to heart issues.
Where does smoking fit into this? Well when you add diving’s increased risk of all these issues, with smoking’s identical risks of heart attack, stroke and higher blood pressure, then you’re effectively increasing your chances of encountering an issue.
Emphysema and air pockets
Emphysema is another condition that can be caused by smoking. The air sacs in the lungs become damaged and aren’t able to supply the bloodstream with as much oxygen as before. It’s thought that many smokers have some degree of undiagnosed emphysema that they’re not aware of.
This can become a big problem when diving, as the pockets of trapped air caused by emphysema can expand when divers make their way back to the surface. This puts them at a far greater risk of suffering from a burst lung or other complications.
Mucus and coughing
Smoking increases the amount of mucus in the lungs, and also paralyses the cilia (small hairs on the lining of the respiratory tract). This paralysis really impacts upon the increased amount of mucus, as it’s the function of the cilia to remove mucus from the lungs. With this out of action, the only way to get rid of the mucus is by coughing. This can spell danger for divers as mucus plugs can create a scenario for sacs filled with air that have the potential to rupture when ascending.
Maybe wait a little while for your cigarette afterwards still…
While the majority of these listed complications are more likely in long-term smokers, there are still some effects to be wary of for those who smoke only occasionally. Even transient exposure to cigarette smoke can cause vasoconstriction. This is a narrowing of the blood vessels that can make off-gassing more difficult. This restriction in the body’s ability to wash out the inert gas can result in an increased risk of decompression sickness.
With so many increased risks while undertaking an activity that already has its fair share, it really is a no brainer to try to avoid smoking if you want to dive. That said, there’s still plenty of divers who smoke, and as long as you know the risks, you can make your own decisions accordingly. While the risks of smoking after a dive are smaller, it’s still preferable to wait at least a little while before lighting up. If you still have any concerns, check with a medical professional to ask their thoughts.
However, even short-term exposure to cigarette smoke results in transient vasoconstriction, namely the narrowing of the blood vessels. This can impair the inert gas washout after a dive:
- Smoking contributes to vasoconstriction which reduces the body’s ability to off-gas efficiently, resulting in a higher risk of decompression sickness.
- Smoking plays a role in platelet aggregation which is something that raises the risk and severity of decompression sickness. Because of the lower levels of transport of oxygen by haemoglobin, smokers tend to have a higher red blood cell count as more are needed to do the same job. This makes the blood more viscous which impairs off-gassing as flow to the peripheries is reduced.