Smoking & Scuba Diving ( am i suiciding? )

Cigarette smoke contains carbon monoxide (CO), which is a poisonous gas that is odourless, tasteless and colourless. An increased level of CO in a smoker will reduce the ability of the red blood cells to carry oxygen. In addition, Cigarette smoke also contains nicotine, which acts as a vasoconstrictor and may therefore increase the risk of DCS.
It is the longer-term issues with smoking and diving that is of greater risk. This includes chronic obstructive pulmonary disease (COPD) that leads to reduced oxygen availability and an increase in carbon dioxide (CO2) retention in the body. This has been implicated as a factor in CNS oxygen toxicity.



DO CHANGES DURING MENSTRUATION POSE ANY RISK?
Again, there are no conclusive studies to answer this question. Repeated exposure to hyperbaric pressure has not been shown to affect hormone regulation, ovulation, or menstruation.
Many women are concerned that menstrual bleeding itself could attract sharks or other predators. However, with tampons this is simply not a problem. It is not even clear that it would be a problem without a tampon; the amount of blood that would be released into the water from menstruation during a 30 or 45-minute dive is minuscule. Some women have experienced a greater menstrual flow when diving, but this has not posed any significant problem either. Thus, it appears safe to dive during the menstrual period providing, of course, the woman feels healthy. Obviously any woman who suffers severe menstrual cramps, headaches, or other symptoms related to her period should refrain from diving until fully recovered.