Especially Caffeine, Nicotine, and Over-the-Counter Meds
Scuba diving is an extraordinary activity that combines physical exertion, environmental pressure changes, and mental focus. What you consume in the hours before a dive—whether it’s your morning coffee, a nicotine hit, or something as common as a cold & flu tablet—can significantly impact how your body performs underwater. Let’s dive into why it matters and what to watch out for.
Caffeine: The Hidden Risk in Your Energy Boost
Caffeine is found in coffee, tea, energy drinks, pre-workouts, and even some medications. While a small amount may seem harmless or even helpful, high doses can lead to serious problems—especially under the physical and physiological stresses of diving.
A recent systematic review of energy drink consumption uncovered multiple cases of cardiac arrest, arrhythmias, seizures, and neurological disturbances directly linked to caffeine intake—even in young, healthy individuals. The stimulating effects of caffeine can:
- Increase heart rate and blood pressure
- Dehydrate the body (already a concern in diving)
- Lower the seizure threshold, particularly when combined with stress or physical exertion
- Cause jitteriness and anxiety, which can mimic or escalate panic underwater
Energy drinks pose an even greater risk because they often contain high levels of caffeine (up to 505 mg per bottle) along with other stimulants like guarana and taurine. The review noted nine cases of cardiac arrest and dozens of severe adverse effects in people consuming these products.
For divers, especially those planning deep or technical dives, that cup of coffee or energy drink could shift from harmless to hazardous under pressure.
Nicotine: Not Just a Lung Problem
Nicotine, whether from cigarettes, vapes, or nicotine gum, has well-documented cardiovascular effects. It constricts blood vessels, raises heart rate, and increases blood pressure. For divers, this translates to:
- Reduced circulation to extremities and potentially to the brain
- Increased susceptibility to decompression sickness (DCS) due to impaired nitrogen elimination
- Greater strain on the heart during ascent and descent
Furthermore, nicotine is a known stimulant, much like caffeine, and when paired with anxiety or high-stress dive environments, can heighten the risk of hyperventilation or panic.
Over-the-Counter Medications: Know What You’re Taking
Popping a cold & flu tablet or antihistamine before a dive might seem like a smart move to “clear things up,” but many over the counter meds can impair your ability to dive safely.
