DIVING AND MENSTRUATION

Separating fact from fiction.

by Samuel Shelanski, M.D.

With the enormous increase in the number of women scuba divers in the past decade, questions have arisen concerning health issues specific to females. Unfortunately, most of the research on under water human physiology has been conducted on male divers, leaving many of the questions pertaining to female physiology and diving unanswered. One of the most common: Is it safe to dive during menstruation? As with many diving-related health issues, the answer is "yes, but ..."

Are sharks attracted by menstrual discharge?

Over the course of their periods, most women lose between 50 to 150 ml (one-quarter to three-quarters cup) of blood and tissue. While this is not a physiologically significant amount, many women fear that this discharge may attract sharks. The truth is that women divers are attacked by sharks less often than men are. In his book Diving and Subaquatic Medicine, Dr. Carl Edmonds suggests that this may in part be due to a repellent effect of some component of the menstrual blood that is released. While this has not been formally tested, it is fair to say that the danger of shark attack from diving during one's period is substantially less than what results from other activities, such as spearfishing.

Am I more susceptible to decompression sickness during my period?

There is currently no direct evidence linking menstruating divers to a higher incidence of DCS than nonmenstruating divers.

A U.S. Air Force study found women to have a 4.3 times higher incidence of altitude DCS than men. All of the afflicted women were menstruating but none had been diving. Another study, conducted by the Hyperbaric Medicine Department at Virginia Mason Medical Center, found that hyperbaric chamber attendants who were menstruating showed a sevenfold higher risk of DCS than male attendants and nonmenstruating female attendants. Again, there is no research to show that this risk applies to divers, though much research remains to be done on this subject.

The reason that women may be more susceptible to DCS during or close to their periods is not known, but it may be related to the bloating many women experience with the onset of their menstrual cycle. This bloating, or edema, is caused by fluid moving from the blood vessels of the body into the body's tissues, resulting in less volume in the bloodstream. The resulting state is similar to dehydration, a risk factor for DCS.

When diving, can I take over-the-counter medicines that relieve menstrual symptoms?

Some over-the-counter medicines, such as Midol PMS and Premsyn PMS, contain diuretics. Diuretics are drugs that help the body eliminate water and relieve the feeling of bloating. Use of these medications, or any type of "water pill," can lead to dehydration; therefore, they should not be taken while diving.

Why is equalizing sometimes more difficult during my period?

Some women complain that they have difficulty equalizing their ears and sinuses when menstruating. Edema may also be responsible for this. The fluid that moves into the tissues from the blood vessels causes puffiness, much in the way that putting a sponge into water makes it swell. If this swelling affects the lining of the sinuses and Eustachian tube, it can make equalizing these spaces more difficult.

Does anxiety during menstruation affect a female diver?

This issue requires good judgment on the diver's part. Many women report feeling increasingly anxious around the time of their period. For a woman experiencing anxiety, making the decision to dive should depend on whether or not that anxiety impairs her ability to respond appropriately in an emergency situation. A smart diver recognizes her limitations, and avoids endangering herself or a buddy. One thing experts do agree on: Sex plays no role in determining successful scuba divers.

Most women will find that they are able to dive without difficulty throughout their menstrual cycles. The main consideration for a menstruating woman is to avoid pushing herself. And if unsure, consult a doctor about whether or not you should dive.