diving on period

Will I Attract Sharks if I Dive with Aunt Flo?

by Sally Camm:

Ladies, imagine you’re on a fabulous tropical vacation, sunny skies, aquamarine waters; the weather is perfect… as is the camaraderie.

And then it hits – your period. To make matters worse, you have plans to go on that fantastic dive tomorrow, and all of a sudden you wonder… will I attract sharks?

The Horror

We’ve all seen the horrific images of shark attacks, and we’ve been taught since we were little that just a drop of blood in the water can attract sharks from miles away. Then shouldn’t it follow that menstrual blood would do the same? Not necessarily.

According to Brian Harper, EMT, DMT and Alert Diver medical editor, “The fluid discharged during menstruation is a combination of tissues and secretions from inside the uterus, including mucus from the uterine glands, degraded blood from the capillaries that feed the endometrium and the glandular tissue of the endometrium.

“Sharks are not known to associate this fluid with feeding opportunities. Although they can certainly detect menstrual discharge, there is little reason to suspect it is attractive to them in the way fresh blood is. It is more likely attractive only in the way any novel sensory stimulus—such as urine, splashing or noises – might be.”

Shark Behavior

Additionally, human blood is not the same as the blood of creatures living in the marine environment. As Ralph Collier head of the Shark Research Committee and longtime shark behaviorist put it, “Our blood is from a terrestrial environment.” His theory is that when sharks detect human blood they don’t react like someone just rang the dinner bell, as they do when there is a marine animal in distress.

To date there have been no scientific studies done on whether women are more or less likely to attract sharks while menstruating, as you can imagine, a controlled study would prove difficult.

Better safe than sorry?

If you just can’t bring yourself to get in the water with Aunt Flo, then don’t. Alert Diver submits that though there is no evidence that sharks are more likely to hassle or bite women who are menstruating, that there are other factors to consider. During menstruation a woman is more prone to dehydration, anemia, emotional stress, as well as irritability, cramping, and headaches and she must decide whether any of these might impair her dive safety.

The SDI Rescue Diver course has some great information on recognizing stress in yourself and others, and will enable you to better evaluate and decide if you need to call a dive.

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4 replies
  1. Larry Michaels
    Larry Michaels says:

    Just a heads up- not everything listed is actually linked to menstruation. Dehydration, anemia, and cramping are all valid concerns, but other symptoms listed in this article are not scientifically linked to menstrual cycles. Irritability is especially troubling as a “symptom”, and should not be considered a diving risk in this case.

    It would be a shame to further dissuade female divers unnecessarily. While it’s important to consider your physical status before any dive, and a check in about things such as headaches and dehydration are always a good idea, diving while menstruating has not yet been proven to be an enhanced risk. The single scientific study suggesting this may be the case had major underlying issues (self-reporting, uneven groupings, ect).

    This article in Time http://healthland.time.com/2012/10/22/pms-is-a-myth-new-study/ and the source article https://www.ncbi.nlm.nih.gov/pubmed/23036262 are both good reads about the science here.

  2. Vic Parr
    Vic Parr says:

    I’m sorry. It is so, so sad that this is even being discussed in an article. Why this is even raised as a question to be answered is beyond belief. There is so many more risks / or even just general issues in diving that could be discussed in this type of forum than the female menstrual cycle.

    Sorry, if i sound irritable….clearly its that time of the month. Or not, and I’m just an experienced female diver that find time spent on this type of article by an accreditation agency outrageous. Surely you have actual real factors/ risk/ issues you could be telling your divers about?


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