To Spliff Or Not To Spliff

A review of how smoking marijuana impacts risk in scuba diving
Text by Dennis Guichard

Life itself is a heck of a ride, isn’t it? The endless rollercoaster of highs and lows. The ecstasy of life's wins when we get a dose of the good. And the withdrawals and depressions of the lows when we get dealt a dose of the bad. Life itself is a drug.

I take cannabis daily. I grind the seeds, along with pumpkin, sunflower, and flax seeds, into a fine powder which I shovel onto my porridge oats every morning for breakfast. The fibre is pure magic for my colon microbiome, and the hemp seeds are packed full of nutritious plant protein, essential fatty acids, vitamins, and minerals. Cannabis is pure gold, but the form I use it for is safe to do so in combination with my scuba diving and hyperbaric activities.

Cannabis has been around for aeons. It seems to have originated in central Asia some 12,000 years ago. There are also records of it being farmed by the Chinese over 6000-years ago. It was treasured for its protein-rich content, oils, and essential fibres for human health.

Hashish, a resin obtained from the flowering buds of the plant, has even been found in Egyptian mummies. The word ‘dagga’, as we know it in South Africa, is a Khoi-derived word meaning ‘intoxication’, which suggests that the locals of that time had also already identified that it had an attractive psychedelic side besides its nutritional content value.

The cannabis plant contains some 450 chemical compounds, of which some 60 are classed as cannabinoids. These bind to receptors on the surface of cells in different parts of our central nervous system to exert their effect.

There are various classes of cannabinoids, with the two of most interest being the psychoactive delta-9-TetraHydroCannabinol (THC) and the medicinal-rich Cannabidiol (CBD). THC is the compound that gets you as stoned as a pebble beach, whereas CBD is the compound reported to have medicinal value for relieving pain and anxiety.

Once consumed, THC is rapidly broken down within our bodies into molecules known as metabolites. As many as 80 different metabolites are formed from THC. Each of these has differing effects on our bodies depending on which receptors they bind to. The metabolism of cannabis, and the production of these metabolites, are also determined by the method of consumption.

Inhaled THC enters the bloodstream quickly and can reach peak levels within 6-10 minutes. Inhaled THC hits hard and fast but also recovers relatively quickly. ‘Normal’ functioning can return within perhaps 2-4 hours. The bioavailability of inhaled THC is only about 10- 35%.
Oral consumption of THC produces a lower psychoactive effect than ingestion, with a
lower peak concentration. Once consumed, it travels to the liver, where most of it is either eliminated directly or metabolised into different forms. The bioavailability of ingested THC is only between 4-12%. THC is highly soluble in our fatty tissue and is slowly released back into the bloodstream from these fat stores. It thus has a longer half-life estimated at between 4-6 hours.
The bioavailability of CBD is relatively low at only about 6% in humans when consumed orally but higher at about 31% when inhaled. The brain, fatty tissue, and organs rapidly absorb CBD. The half-life of CBD is estimated at between 18-32-hours.

Women tend to absorb cannabis metabolites slower than men but also take longer to eliminate them. THC can be detected in the blood for up to about 12 hours, in our saliva for approximately 24 hours, and in our urine for about 30 days. THC residue can be detected in hair for up to 3 months in chronic users.

Smoke from cannabis contains many of the same toxins, irritants, and carcinogens as tobacco smoke does. Smoke inhalation can cause increased coughing and sputum production due to epithelial cell injury along the respiratory airways. This damage then triggers goblet cell production, leading to increased mucus production in the lungs, increasing the risk of mucus plugs, air trapping, and gas embolism. Smoking can also cause the lungs to become hyperinflated and develop patches of inflammation.

Like tobacco smoke, a spliff also produces carbon monoxide, which binds chemically to the haemoglobin in our red blood cells and reduces the oxygen-carrying capacity of our blood, which we instead need when diving to provide our muscles and organs with energy so that they can function properly. The carbon monoxide can also cause an increase in brain blood flow which might elevate the risk of cerebral decompression sickness after diving. Smoking after a dive also interferes with bubble mechanics hindering the effective elimination of inert gas.

Cannabis THC consumption negatively impacts our concentration span, reaction time, short- term memory, hand-eye coordination, time perception, and decision-making, making us stupidly invincible. THC also causes an increase in heart rate and blood pressure—all a recipe for disaster when combined with scuba diving.

DAN’s guidance on consumption of cannabis is to avoid diving for at least 6-8 hours following ingestion of any ‘cookies’. Impairment from smoking a spliff is likely to be shorter. Impairment is commonly both dose- dependent and bio-individual, but blood THC levels seem to drop back to a ‘normal functioning’ level after perhaps 4-hours.

I might be one of the dullest people on earth, but ‘spliffing’ is certainly not for me. It is my ethos that we have no real purpose here on earth, in the relatively short time across the
aeons that we enjoy being here, other than to engage with the experience of being as fully as possible.

Life’s an endless rollercoaster that we need our wits for, and scuba diving is always mind- blowing on its own. When I get away on weekends to blow some bubbles off our coastline, I don’t even consume alcohol. When I scuba dive, I always want to be as alert and well-rested as possible to engage in the magic of diving fully. There is so much to see and absorb in life as much as in scuba diving, that I just don’t know why anyone would want to numb the experience of being from the full potential it offers. But everyone fairly to their own.

My ‘hemp seed mix’, which I shovel onto my breakfast porridge oats daily, is nutritious. It is a healthy way to start every day and to ensure I can optimise my love of scuba diving and the experience of being.