Swimming while menstruating is perfectly safe, hygienic, and entirely normal. Athletes at all levels regularly participate in water activities during their cycle. The potential for flow while submerged is a common concern, but it is primarily a matter of physics and physiology, not a reason to avoid the pool or ocean. Understanding how the body interacts with water can help demystify the experience and provide confidence for a worry-free swim.
How Water Pressure Affects Menstrual Flow
The sensation that your period stops when you enter the water is due to hydrostatic pressure. This is the pressure exerted by the surrounding water against your body, which is significantly greater than the pressure of the air outside the water. Hydrostatic pressure counteracts the force of gravity, which normally pulls menstrual fluid out of the body.
This external pressure against the vaginal opening effectively keeps the menstrual flow inside the body, reducing or temporarily stopping the release of blood into the water. The menstrual cycle itself does not pause; the uterine lining continues to shed, but the fluid is contained by the pressure differential. This containment is not absolute, however, as a sudden change in abdominal pressure, such as a strong cough, sneeze, or strenuous movement, can temporarily overcome the hydrostatic force.
When you exit the water, the external pressure immediately disappears, and gravity resumes its effect, meaning the flow will quickly restart. Relying solely on water pressure without an internal collection method can lead to leakage immediately upon leaving the pool or sea. The relaxation of muscles in warm water also helps to lessen the discomfort of menstrual cramps, allowing for greater enjoyment of the physical activity.
Practical Methods for Managing Flow While Swimming
The most reliable way to manage flow and ensure comfort while swimming is to use an internal collection product. Tampons are a highly effective option for water activities, providing discrete and secure protection. Because tampons are made of absorbent material, insert a fresh one immediately before entering the water, as the tampon may absorb some surrounding water.
Changing the tampon as soon as you finish swimming is recommended to prevent discomfort from absorbed water and to maintain hygiene. For competitive swimmers or those planning long periods in the water, a menstrual cup or disc offers a superior solution. These products are typically made of medical-grade silicone and work by creating a gentle seal against the vaginal walls, collecting the fluid instead of absorbing it.
The primary benefit of a cup or disc is that it does not absorb water, making it a highly reliable choice for extended time in the water. It also eliminates the need for an immediate change upon exiting, unlike a saturated tampon. Period-friendly swimwear, which features an absorbent, built-in lining, is another option, though it is usually better suited for lighter flow days or as a backup. Conventional pads or panty liners are not suitable for swimming because they become waterlogged quickly and lose their adhesive backing, rendering them ineffective.
Safety, Hygiene, and Debunking Myths
Concerns about the hygiene of swimming during menstruation are common, but the risk of contamination or infection is extremely low in properly maintained water. Swimming pools use chlorine or other halogens to neutralize bacteria and pathogens, which effectively sanitize any minuscule amount of menstrual fluid that might be released. In the vast volume of water found in a pool or the ocean, any blood is instantly diluted, making it undetectable and harmless.
The amount of blood lost during a period is small, typically ranging from four to twelve teaspoons over several days, and the amount released while swimming is negligible. Swimming during your period carries no increased risk of infection from the water compared to swimming at any other time. The idea that menstrual blood attracts aquatic life, specifically sharks, is a pervasive myth with no scientific basis.
There is no evidence to suggest that people who are menstruating are more likely to be attacked by sharks; the vast majority of recorded shark bites involve males. Another common misconception is that swimming will make menstrual cramps worse, when the opposite is often true. Physical activity, including swimming, encourages the release of endorphins, which are natural painkillers that help reduce the pain and discomfort associated with cramping.