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How long sperm live depends largely on the environment in which they find themselves. We have summarized everything you need to know about the lifespan of sperm.
How long sperm live in the testicles
The testicles are responsible for producing sperm. They provide ideal conditions, especially in terms of temperature.
- At 35 degrees, the temperature of the scrotum is slightly lower than normal body temperature.
- From the testicles, the sperm travel to the epididymis, where they mature and are stored.
- Sperm can live in the epididymis for up to one month.
- Unless the man has had a vasectomy, i.e., sterilization, the sperm enters the woman’s vagina together with the seminal fluid during sex.
Lifespan of sperm in the female body
A woman’s fertility influences the lifespan of sperm. This is because there are fertile and infertile days in the predictable female cycle. The environment in the vagina also changes during this time.
- On infertile days, the vaginal environment is acidic, which is not a good environment for sperm. They usually die within minutes.
- The situation is different on fertile days. Here, sperm can reach the uterus or fallopian tubes due to the more favorable environment.
- Once there, they have up to five days to fertilize an egg. Then they die.
- Incidentally, sperm have a very short life span when exposed to air or on the skin. They simply dry out. In most cases, the life of sperm ends after just a few minutes.
Other conditions for sperm survival
Sperm can survive for very different lengths of time in different environments. Inside the body, i.e., in the female reproductive tract, sperm find the most ideal conditions and can survive for up to five days, sometimes even up to seven days.
- This high survivability is mainly due to the fertile cervical mucus, which has a nourishing and protective effect, and to an alkaline pH value during ovulation. A body temperature of around 37 degrees Celsius also supports their survival optimally.
- Outside the body, for example in a condom, sperm can theoretically survive for several hours if the condom is closed and protected from drying out. However, if condoms are opened or there is no protection against drying out, sperm die much faster. Some condoms are coated with spermicides on the inside, which kill sperm within minutes.
- In water, such as in the bathtub or swimming pool, sperm die very quickly, usually within seconds, as water causes the cells to swell and destroys them. In addition, the pH value, temperature, and chemicals often contained in water are unfavorable for sperm.
- On absorbent surfaces such as clothing, bedding, or towels, semen dries quickly, causing sperm to die within a few minutes. They are particularly unlikely to survive on dry fibers. Only in very specific situations, such as large amounts of semen on less absorbent materials, is survival theoretically unlikely but possible.
These factors also play a role
The lifespan of sperm depends crucially on three factors: temperature, humidity, and pH value. These factors create the optimal conditions for the survival and functionality of sperm, both inside and outside the body.
- Sperm thrive best at body temperature, around 37 degrees Celsius. This stable temperature supports their motility and viability in the female reproductive tract. Extreme temperatures, especially heat (e.g., saunas, hot tubs) or cold, significantly reduce viability as they damage cell structures or reduce motility. Outside the body, temperature fluctuations quickly lead to sperm death.
- Sperm need a moist environment to survive. Dehydration through contact with air causes them to die within minutes or hours, as they need the fluid that surrounds them (seminal plasma). Moist surfaces or mucus protection in the female genital tract provide protection and thus prolong their lifespan. Without moisture, they cannot remain functional.
- The environment in the female reproductive tract is normally acidic (pH value four to five), which is harmful to sperm. However, during fertile days, cervical mucus changes to a slightly alkaline pH of about 7.2 to 7.8, which is optimal for sperm.
- This alkaline environment protects the sperm, prolongs their lifespan up to five days, and supports their motility. Deviations from the optimal pH quickly lead to sperm death. Many contraceptives make use of this effect.
- Why are these factors crucial? Sperm are sensitive cells that can only remain motile and capable of fertilization under certain conditions. Temperature ensures that their cell functions are maintained, moisture prevents dehydration and cell damage, and a suitable pH value protects against a lethal environment and promotes motility.
- Together, these factors create a life-friendly environment that allows sperm to remain viable in the female body for several days and increases the chance of fertilization.
Pregnancy from sperm in water?
Pregnancy through sperm in water, e.g., in a swimming pool, lake, or bathtub, is practically impossible.
- Sperm die very quickly in water, usually losing their motility and fertility within a few seconds. Soap and other additives in the water also make it difficult for them to survive.
- You can only get pregnant if fresh sperm enters the vagina directly, for example through unprotected sexual intercourse or direct contact with sperm (e.g. via the hands).
- However, water alone does not protect against pregnancy; if you have sex in water and ejaculate into the vagina, pregnancy is just as possible as anywhere else.
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