It is perfectly safe to swim in the ocean while menstruating. This common question is often rooted in misconceptions about hygiene and safety. Menstruation, the periodic shedding of the uterine lining, does not present any medical or public health reason to avoid swimming. The process involves the release of menstrual fluid, which is easily managed during water activities.
The Truth About Menstruation and Marine Life
The most persistent fear surrounding ocean swimming during a period is the myth that menstrual blood could attract sharks or other marine predators. Scientific evidence consistently shows this is not a safety concern. The total volume of blood lost during an entire menstrual cycle is small, typically ranging between 30 and 80 milliliters.
The amount of blood potentially released into the vast ocean is negligible, especially compared to blood from a small marine animal or a minor cut sustained by a swimmer. While sharks possess a highly sensitive sense of smell that detects organic material, there is no evidence that menstrual fluid has ever been a factor in shark encounters. Any bodily fluid, including urine, can be detected, but this does not equate to predatory attraction.
Marine biologists note that the low concentration and volume of menstrual blood are unlikely to trigger a feeding response. Many people, including divers and surfers, safely enter the water while menstruating without incident. The risk of a shark bite remains extremely rare, regardless of menstrual status.
Management Methods for Swimming Comfort
For comfort and hygiene while swimming, internal menstrual products are the most effective options for flow management.
Internal Products
Tampons are absorbent products inserted into the vaginal canal to soak up the menstrual fluid. It is advisable to insert a fresh tampon immediately before entering the water to ensure maximum absorption. Menstrual cups, typically made of medical-grade silicone, collect the fluid rather than absorbing it. Unlike tampons, cups do not absorb the surrounding water, making them a secure option for extended time in the ocean. Both should be removed and changed or emptied shortly after exiting the water to maintain hygiene.
Other Options
Period swimwear, which features an absorbent and waterproof layer, offers another layer of protection. This option can be used alone on light flow days or worn as a backup layer alongside an internal product. External products like pads or panty liners are not suitable for swimming. They are designed to absorb liquid and will quickly become saturated with water, making them ineffective.
How Water Pressure Affects Flow
When a person is submerged in the ocean, the flow of menstrual fluid is often temporarily slowed down or stopped entirely. This phenomenon is a matter of basic physics, specifically the effect of hydrostatic pressure. Hydrostatic pressure is the pressure exerted by a fluid at equilibrium due to the force of gravity, and it acts equally on all surfaces of the body while submerged.
This external water pressure acts against the vaginal opening, counteracting the force of gravity that would normally pull the menstrual fluid out. This creates a temporary barrier that prevents the fluid from exiting the body while the person is in the water. The process of menstruation itself continues internally, even if the outward flow is paused.
However, any action that increases internal abdominal pressure, such as a strong cough, sneeze, or laugh, can momentarily overcome the external hydrostatic pressure, potentially allowing a small amount of fluid to be released. The flow immediately resumes its normal rate once the person exits the water and the hydrostatic pressure is removed. Therefore, using an internal product for management remains necessary for continuous protection before and after swimming.