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December 5th, 2000, 09:14 PM
Just curious...

Everybody said monthly period does not affect scuba diving activities. Any experience in diving with sharks when you're having your monthly period?


December 6th, 2000, 05:16 AM
There is no evidence to suggest sharks are affected in any way by menstruation. Actually, most evidence suggests sharks are not attracted to human blood at all. Dive and enjoy yourself.


December 6th, 2000, 12:35 PM
The only problems I have had with my periods during diving is the occasional discomfort from cramps. I don't like to take medications during diving so if the cramps are very bad, I just skip a dive or two.

The use of Tampons is preferable to pads.

One thing you have to be aware of is you are more prone to dehydration during your period. Be sure to drink plenty of water, more than you normally do.

Enjoy your diving!

December 6th, 2000, 07:02 PM

Common knowledge is if you are bleeding in the water, even if it's only a small wound, the smell of blood attracts sharks nearby - it smells there's something yummy. Then you are prone to shark attack.

It's in every movie :-)

Of course, shark is more interested in swimmer and surfer than to diver. Still...a diver with a small wound, that should attract a hungry shark, no?


In dive travel I usually just take medicine (I forget the name of it) to delay it for several days. With such wet environment, won't a tampon size explode to an uncomfortable size?


December 6th, 2000, 07:16 PM
<< won't a tampon size explode to an uncomfortable size? >>

No, it won't. It will absorb the mentrual flow only and will expand to fit your vaginal cavity and is easily removed. In other words, it does not absorb water like some think. The pressure at depth when diving also has no effect. I've noticed no difference in wearing them in the water.

You can wear them with comfort, not to worry.

Mario S Caner
December 6th, 2000, 07:26 PM
I've been asked this question by students before, but never really had any proof to my answer. Where can I find the data I'm looking for?


December 6th, 2000, 09:15 PM
In the early 1970's David Baldridge conducted experiments that indicated mammal blood is not particularly attractive to sharks. His studies (he had been maintaining the Shark Attack File) also indicated many shark "attacks" suggested the shark was not trying to feed, but had motives other than hunger for the incidents. Incidentally, of the 1,165
cases in the Shark Attack File (maintained from 1958 till 1969) 1,080 (93.1%) of the attacks were on males, this would seem to indicate blood from menstruation does not attract sharks. I'll look for additional documentation.

As for "common knowledge" - well, it's frequently wrong. In the immortal words (pun intended) of Lazarus Long, "If 'everybody knows' such-and-such, then it ain't so, by at least ten thousand to one."

I've been in the water with sharks on numerous occasions when I've been bleeding from various wounds. To the best of my knowledge I've never had any shark take note of me as a result.


December 6th, 2000, 09:30 PM
Hi Everyone,

There is an interesting article at Women in Scuba ( about women's issue in diving. The article was done by Jacalyn Robert ( of Texas Tech University; Department of Health, Physical Education, and Recreation.

The article has brief sections on diving during menses and diving while pregnant. Just an interesting bit from the article

"There is no evidence of increased shark interest in a menstruating female. The hemolytic blood associated with menses may instead act as a shark deterrent (Edmonds, et al., 1992, p. 65)."

So, based on this bit of info, it would make sense that there are more shark attacks on men than women.

Also, my experience has been similar to Dee's. I haven't had a problem diving while using Tampons. It's just like using them on any regular day of you monthly period. Just be sure to stay well hydrated to avoid increase risk of DCS.


Mario S Caner
December 6th, 2000, 11:05 PM
Thanks for the great info, I'll be sure to look it up and take a looksy.


December 9th, 2000, 08:00 PM
As a female working full time in the tropics this is something that I get ask a lot about.
I personally have never had any problems with sharks.
As I understand it and in easy to understand english, the blood produced during our periods is old blood. Sharks like fresh blood!
Also once the body is in water we temporarily stop bleeding so in theory (and I have never tried this) you could dive with out wearing tampons. The only problems being is when you get out of the water within a few minutes you will continue to bleed. So if you have a long boat journey or there are no facilities nearby, diving without a tampon would not be such a great idea.
I know that I don't have any solid "proof" but after 10 years experience sharks have never been a problem. Maybe I'm just very lucky!!!!!

December 12th, 2000, 08:40 AM
Dear Ray

I had a Divemaster working with me during a Rescue Diver class that was harrased by 4 to 5 gray sharks while she was waiting to be located and rescued. She later confided in me that she was on her period. I was always told that it made no difference if a woman was on her period or not but after that, who knows? Old blood? I've seen old cow and fish blood attract sharks. Why not other old blood?


December 18th, 2000, 02:08 AM
I was diving in the maldives with my wife who at the time had her period and I have to agree we too were hassled by a large grey reefy, he cirled us 3 times before displaying a rather strange aggressive pattern. We backed off and he followed us for about a 100 meter swim.

I do not believe mammal blood does not interest sharks, you only have to look at seal and seal blood in the water and they are not fish!! If a seal is attacked then the sharks go mental.

There is far too little research about Sharks to be able to say yes it does or no it doesnt effect them, all I can say is I think it is Fantastic and a priviledge to have a large shark so close so if it is the case I am greatful to my wife, If I was a woman i'd be a little concerned.

And must throw away those Yum Yum coloured fins!!

December 18th, 2000, 03:10 PM
LadyDiver ...

So, based on this bit of info, it would make sense that there are more shark attacks on men than women.

It just goes to show you that Sharks ARE NOT mindless killing machines ... They are smart enough to know not to mess with women every 28 days or so ... hehehe ... That's more than can be said about many of us men ... LOL

I can think of many a time where the thought of getting cute or poking at a MAKO that's having a bad hair day, almost seemed "Intelligent" compared to crossing the path of the species otherwise known during such times as the "Pissedoffatus Femaleus"!!


December 18th, 2000, 04:41 PM
Have to tread very carefully here!! As I dont want to offend.

If I was a woman I think it would not matter who said what about safely diving with a period or not the fact of the matter they are currently still doing tests on women diving with their periods and have no real results to proove either way. Personally, to me blood is blood old or new and sharks like blood, so if I were a woman it would always be on my mind regardless, sorry.

December 19th, 2000, 02:49 AM
Are we right to comment on this subject after all we are not exactly qualified to comment here.

Well I may not be a Gynacologist ( Or a good speller ) but we are all commenting on something we know so little about.


December 19th, 2000, 06:59 PM
Walter is right. Aside from shark attack files, tests conducted at RSMAS (Rosenstiel School of Marine and Atmospheric Sciences) at the University of Miami and other institutes indicate that sharks are not attracted to human blood. They are attracted to fish blood and digestive juices.

The idea that sharks are attracted to human blood comes from the movies and a time when we knew far less about sharks than we do now. It comes partly from faulty reasoning and assumptions. It has been known that sharks are attracted to bleeding fish (as when spearfishing) and the assumption was probably made that they are attracted to all blood.

In cases where sharks attacked humans, blood was probably thought to be the main factor until we learned much more about them and learned of other, more likely triggers, such as low frequency sound vibrations.

Narc, being male does not disqualify someone from being able to address this issue or others that affect women. Men can read scientific data and pass on what doctors have said just as easily as women can. The issue is information about blood and sharks, not actual experience with menstruation.

Mario S Caner
December 20th, 2000, 01:23 AM
I'm going to have to go with vr on the issue of guys being able to contribute to this particular thread. It does after all involve us too. I'm sure that you have been in the water with a female during her menstruation cycle.

I for one wanna know!


December 20th, 2000, 01:36 AM

The hopes are that if we can generate enough interest, concern and inquiries that maybe the medical communities will be inspired to dig deeper and take interest in these subjects. Probably just as important is to dispel rumors and set the records straight on the myths and create a safer and more knowledgeable group of divers.

One of the real great things about this forum is we are blessed with the likes of Ernest "scubadoc" Campbell, Michael "Dr Deco" Powell, BillP, John Reinertson and others within the Professional Medical Community that can keep us "in check" and are willing to share what knowledge that is known about these subjects.

For those of you newer to Scuba will quickly find out there are just LOADS of rumors and myths that so many believe are FACT and already we have all learned stuff here from some of the best of the best ....


December 22nd, 2000, 08:41 PM
If you're going diving with me and see a me chowing on a chocolate bar and a bag of Lay's potato chips with a mean look on my face?.....don't ask! :) Case

December 22nd, 2000, 08:55 PM
Smack! :goofy:

You walked right into that one Mario. Be careful about what you want to know! ;)

:p Jennifer :p

Mario S Caner
December 23rd, 2000, 02:07 AM
I own the most complete save a dive kit, out of anyone I know. It's a large Pelican box stuffed with just about everything you could imagine... And don't you worry, I've got plenty of chocolate and other things to nibble on too...

Mario :D

December 23rd, 2000, 01:03 PM
Ho, Ho, Ho, Mario! So you have candy bars, potato chips AND sutures in your kit?!

Mario S Caner
December 23rd, 2000, 01:23 PM
Doesn't everyone? You just never know what you might need at the beach... though it is a little ridiculous to some, other's have thanked me over and over again. Umongst the arsenal there are things from hair ties & extra socks to unused regulators, brand new computers, inflators, hoses and even a hand held sonar... overkill... perhaps but I've got 'em so why not just pack em up and see if they might come in handy.

Happy Holidays!
Mario :D

December 23rd, 2000, 05:28 PM
You could definitely teach me the right way to pack! I'm sometimes lucky if I remember my sun screen in the morning! Thank goodness the boat is well stocked!
Happy Holidays to everyone!!!!

Mario S Caner
December 23rd, 2000, 06:26 PM
I'm almost reluctant to continue, I usually have at least 3 or 4 different sunscreans with differing SPF factor's for different days and personal preferences. I use the most while sailing though... SPF trillion-point-five. LOL!

Mario :D

December 25th, 2000, 03:58 PM
There is a nice Power Point Presentation that you can download on this subject at

December 30th, 2000, 02:28 PM
...have done shark feeding dives while in the midst of my period many times. It's a non-issue and if anyone tells you otherwise, they don't know what they're talking about.

January 2nd, 2001, 01:39 PM
Man this is a flaming hot topic.:fire: Ok, heres' my 2 cents. I also have been on a shark feeding, with women that had Aunt Gertrude visiting. No problems at all. The sharks were much more interested in the fish blood.
As for Mario, and your 'kit' I never saw anyone with better things then what I keep in my GI JOE Scuba lunch box, until I read what you bring. Man I want to dive with you! I'll share my " Shock Tarts" they're the best when you get out of the salt water.=-x
Dive the Planet.:loopy:

Mario S Caner
January 2nd, 2001, 02:50 PM
LOL, just kidding by the way... LOL! In all seriousness, I'd love to dive with you and all the other members we've been busily building friendships with. I'll be sure to bring my arsenal with me!

Mario :D

January 2nd, 2001, 03:50 PM
Ha! " I'll show you mine if you show me yours"! Very clever you bad boy(I love bad boys):tease:
Maybe I'll bring some extra treats to DEMA to play with. Ha!;)

Mario S Caner
January 2nd, 2001, 04:17 PM
You definitely have my attention... as if I didn't have enough motivation to be at DEMA already... until then, @>---;-----

Mario :D

January 3rd, 2001, 01:53 PM
I do believe we're flirting on these boards.:1st: Be careful, Aunt Gertrude could be watching! LoL

January 3rd, 2001, 06:11 PM
Based on the replies to the subject:

1. Sharks are more interested on the blood of the fish.
2. If there is no blood of fish around, sharks do get interested in human blood, in this case: old blood of monthly menstruation.

LOL...guess I will stick to my old way: no dive during monthly period.


Mario S Caner
January 3rd, 2001, 10:16 PM
I just can't wait for DEMA! I gotta go start packing now!

P.S. I'll be the one next to the guy with the Leopard Print Suit... by the way where has Don been hiding these days?

Mario :D

January 3rd, 2001, 10:28 PM
Ray wrote: "2. If there is no blood of fish around, sharks do get interested in human blood, in this case: old blood of monthly menstruation.
LOL...guess I will stick to my old way: no dive during monthly period."
You apparently never read my post so it's your loss. You CAN dive during your monthly period with NO problems whatsoever. I've been diving for 10+ years & NEVER cancelled a dive due to the fact that I was having my period.

January 10th, 2001, 10:00 AM
I haven't been diving long and have never dived with sharks but there's no evidence at all for them being attracted to period blood. The very idea seems to me a bit sensationalist, like something the press would latch onto because they think it'll grab peoples' attention.
After all, the blood is not floating around in the water (hopefully). I know sharks can smell blood a long way off but if this was even an issue I think there'd be a bit more evidence.

April 12th, 2001, 10:39 PM
I have dove both with and without periods....thank God as I age (no pun intended), the periods become fewer and fewer!! Never had a concern about sharks. However, if you are concerned, pop on a drysuit...then it is not an issue at all. You can pick up very light drysuits for diving in warmer waters.

aging ages!!

April 17th, 2001, 07:42 PM
Not beating a dead horse however, I've never had any problems while diving & on my period! Tampons are the most comfortable for me in the sea & on land.
And I don't know about you, but if a shark (or any other living creature) thought of messing with me on the first day of my mense...well, THAT would get very ugly! We'd need the vast array of concoctions found in Mario's kit or Natasha's GI Joe lunchbox to fix him.

April 19th, 2001, 05:57 AM
This is certainly a fascinating topic.... I am new to diving and have been wondering about it myself. I actually had my period the day I was certified, and while I knew there weren't any sharks around, I had to wonder about it. I guess it is true though that blood does not actually come out while you're down there, whether you're using a tampon or not, so surely that says something.

I'm interested to see what else comes up in this discussion. (and both Mario's and Natasha's kits/lunch boxes sound amazing... :) )

May 20th, 2001, 12:55 AM
This sounds a lot like the debate with grizzlies- and they don't seem to preferentially attack menstruating women, either. I suspect it's just spread around by a few manly men who would like to keep us little women home and safe.

But, anatomically speaking, I doubt very much that menstrual blood gets in the water if a female is wearing a fresh, properly-sized tampon. The vagina is watertight (unless the water is forced in, as in water skiing- ick). Water doesn't get up there to wash the blood out. That is why tampons don't expand when the wearer is in the bathtub or under the sea.

Also, for convenience's sake, if you are taking the Pill, ask your gynecologist how to manipulate the placebo week to avoid having your period when you plan to dive. (Unless you dive all the time, in which case you have no reason to whine, you lucky devil).

May 23rd, 2001, 12:38 PM
While on my last dive trip I unexpectedly started…7 days early. Because my cycle is regular I was unprepared and was given “slender” tampons from another woman onboard the boat. My first day is usually a heavy flow and I knew I would probably bleed through a slender. Heck, I was desperate & if I had to change every hour for one day – it beat having to create makeshift pads! Also, as noted on the board earlier, being in the water often stops the flow…so I went diving!

We were diving a wall that began at 15 feet & sloped down to 1,000 feet. Throughout my dive, I stayed at 45-50 feet occasionally looking out at “the blue” just in case I saw something big. About 40 minutes into the dive I saw a Gray Reef Shark, about 10 feet long (no kidding) cruising the top of the reef, heading my way. I thought nothing about my period and instead, video taped the magnificent creature as he glided past me. When we returned to the boat I had bled through the tampon and changed immediately.

1-˝ hours later, we hit the water again…same spot…still bleeding heavy and using a slender sized tampon. 20 minutes into the dive I spotted the big Gray Reef Shark again…in 50 feet of water again. My husband had the video this dive so I bolted to find him to so he could capture the shark on film also. I found my husband & signaled him to follow me to where I thought the shark would be now and found him! About 20 feet, the opposite direction I spotted another Gray Reef Shark! (This one was about 8 feet long). The two sharks were heading toward each other…me somewhere in between. They never showed aggression, they just cruised by me. In the back of my mind I thought; “I’ll bet I’m bleeding through again…now what was it they were saying on the Scuba Board about women/periods/sharks?”

It wasn’t until the following day that I “hit the water” again…same spot. My flow was back to normal and my “slender” absorbed perfectly and I saw no sharks.

Do you think its coincidence? What are your thoughts?

May 23rd, 2001, 02:51 PM
I think it could be a coincidence, but then again, the sharks might have just smelled the blood, even though it was old, and been curious as to what was around. Seeing no prey in distress, or YOU in distress, they weren't stimulated to attack or take a test-bite.

When I went diving in Cozumel I was also on my period, and I wore a pad because my last experience with tampons I had gotten sick, with all the symptoms of TSS. I only saw one shark, a nurse shark, and it was quickly moving off in the other direction. I think that ANY kind of blood, old or fresh (Chum blood is kinda yucky and old) will get a shark's attention, but they won't get too interested unless theres a target on the surface, or theres a wounded target in the water.

May 27th, 2001, 12:33 PM
No matter what everyone says, I am NOT going to stop diving during my periods and would never consider telling guests at the resort I work at that I am having a period at the moment.
As well as being an instructor I do also quide dives in waters where I see sharks on every dive. I have never been asked by guests nor has the subject come up.
We do not feed sharks here and in the 15 years the island has been open to divers, we have never had an attack (touch wood!).
I would encourage women to dive at any time and if a man is that worried about it, perhaps he can do his diving else where!

June 24th, 2001, 06:46 PM
I have been diving for 6 yrs. and have no problem diving while on my period. There have been no interest for sharks that I have noticed. As far as not diving while having period.... I would never get to dive. LOL It seems every dive trip even if it's not time for it I get it anyway. I had an instructor tell me it was because of the pressures at depth. She also would start early if diving.

July 18th, 2001, 11:24 AM
While there is no evidence that sharks have any more interest in a menstruating female, having your period while diving is just a pain.

I read some interesting studies about using birth control pills; if you are on the pill you might want to talk to your doctor about extended use. The modern woman has 4-5 times more periods than she was probably ever meant to have from an evolutionary standpoint. Think about it: women 100 years ago started their periods at an average age of 16-18, had children, nursed for multiple years, entered menopause earlier, and had fewer periods overall because of it.

As a result of conversations with my own doctor, I'm now taking pills consistently for 3 months and THEN taking the week-off cycle. I'll end up having only about 4 periods of year. In other words, I'm going through the entire Northern New York wreck diving season without having to worry about it AT ALL.


July 18th, 2001, 12:28 PM
I've taken the pill through 2 months so I wouldn't get my period while traveling. But after three months I'm afraid I'll have break through bleeding and it will defeat the purpose. Has that ever happened to you?

July 18th, 2001, 02:03 PM
So far, so good! No problems yet. It's probably somewhat individual, though, and I have never been prone to breakthrough bleeding.

July 22nd, 2001, 09:15 PM
What an excellent idea!! I haven't taken the pill for many years so I've never thought about it in the context of diving. Thanks for the idea.

sea nmf
July 23rd, 2001, 04:08 PM
I hope when there is a research project started on this subject that they come here for volunteers!

I'll be the first to sign up!

July 23rd, 2001, 05:48 PM
Birth Control Pills provide women with a week off, only because the inventors (2 men) thought that women psychologically wanted a period to make sure they were "okay" after taking pills for 3 weeks.

There actually is no medical reason you must take that week off, so this is why Doctors will prescibe overlapping weeks of the Pill so that you don't have to have your period.


August 16th, 2001, 07:02 PM

I am curious - you said you take some medication that delays your period a few days - what is it?

Jai Bar
August 15th, 2013, 01:14 AM
Ray wrote: "2. If there is no blood of fish around, sharks do get interested in human blood, in this case: old blood of monthly menstruation.
LOL...guess I will stick to my old way: no dive during monthly period."
You apparently never read my post so it's your loss. You CAN dive during your monthly period with NO problems whatsoever. I've been diving for 10+ years & NEVER cancelled a dive due to the fact that I was having my period.

+1. .

October 22nd, 2013, 12:20 AM
Actually glidingray, this has been proven false quite a few times in recent studies. Heck, even Myth Busters proved if false by dropping some tuna blood in a shark tank and the sharks went nuts. Then they dropped some human blood and they could care less. Even when it was right next to their face.
It has also been proven false that sharks can smell a drop of blood miles away or as some say "one drop in an Olympic size swimming pool".
What has been discovered is that it is more like one drop of blood could be detected in 25 gallons of water. I have even started seeing that new drop/25 gal quote in many publications and even Shark Week is now using it.

Do not believe what is in "every movie".

And btw sharks are more interested in swimmers and surfers primarily because
a.) they are underneathe them, the power position is under the prey
b.) they are more prone to mistaken identity of "normal prey"

October 22nd, 2013, 01:44 AM
Never been an issue. I have never had anyone say they have or ask me if I have my period before going for a dive - and id be rather curious as to what sort of person asks that in the first place!. Have never had leakage issues but have cut my hand underwater with 6 large reefies about 15m away who did absolutely nothing but look over and continue on their way. When i am travelling I take the pill so its not an issue - and also because i cannot bring myself to ask for tampons in countries that call them mankins or other wierd things I cannot pronounce - I have never had my doctor say you need to take a break x cycles.

Goodtime Adventures
November 17th, 2013, 11:27 PM
+1 with the above. I get asked this question very regularly.
Never had a problem and I've been in the water with sharks during my period countless times; they could not care less.

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