Skip to main content

Course Outline

Diving demands a certain level of fitness. Maintain a good cardiovascular system and an average level of fitness and weight for your height. Some of the benefits of becoming fitter are lower blood pressure, better heart regulation, greater blood flow, more efficient lungs, and lower heart rate. These effects are beneficial to scuba divers and can make diving even more enjoyable.

Health Risks With Tobacco, Alcohol, and Trans-Fat Food

Tobacco is a highly addictive substance, and it is one of the leading causes of chronic diseases. Its active ingredient, nicotine, is a highly toxic alkaloid that is fatal in doses of 60 milligrams. An average cigarette provides a dose of 0.5 milligrams. When a person smokes, there is almost an immediate effect on the respiratory, nervous, and circulatory systems. A single cigarette will paralyze the cilia, which are tiny little hairs in the lungs, for up to 20 minutes.

Smoking causes an increase in the mucous production almost immediately and interferes with the oxygen uptake in the lungs. The blood vessels within the body will react to tobacco smoke by constricting, which will in turn increase blood pressure. This eventually predisposes a diver with heart disease to a higher risk and susceptibility to DCS because the circulatory efficiency is reduced. Another risk that a diver faces is the possibility of mucous plugs in the sinuses and congestion in the lungs. There is a high probability that gas trapped behind these plugs may cause a pulmonary barotrauma. Smoking is the single most lethal carcinogen in the world.

Alcohol, after tobacco, is the second most widely used addictive substance in the world. Alcohol intoxicates and decreases performance. Combine this with the effects of nitrogen narcosis at depth, and the diver will have a real problem. The ability to function and to note changes in equipment and parameters will be severely impaired. Alcohol further promotes heat loss, increases the risk of vomiting underwater, and is a diuretic. It causes the diver to urinate more, leading to dehydration and a high susceptibility to DCS. Always hydrate with water.

A meal high in trans fat produces an immediate change in the circulatory system by slowing it down and creating a phenomenon described as sludging. After about six hours following the meal, the sludging can be so severe that it may be enough to virtually stop circulation in the smallest of blood vessels. For a diver, this can be a serious problem and may lead to DCS.

Dive Refresher

If 6 months have passed from the start to the finish of your program, there are special considerations you must follow. This is because skills will diminish if you don’t practice them, and your initial skills should be completed in this time frame. For this reason, it is recommended that if you haven’t dived within 6 months from your last dive, you should complete a refresher with an instructor or divemaster. If you have not dived within 12 months, a confined water refresher with an instructor is required before any open water training dive. The refresher will include but is not limited to the self-rescue skills, mask removal and replacement, and buoyancy.

  • Unit 7 of 9
  • Topic 8 of 8
  • Page 4 of 6