Technically, there are no factors which affect semen speed, since semen is the fluid in which sperm are found. It is comprised of fructose and other substances, and it provides a protective barrier for sperm so they can survive the acidic environment of the vagina. The speed of sperm, however, can be affected by unhealthy lifestyle choices or genetic factors. Many people use the terms “semen” and “sperm” interchangeably, although they are actually two separate entities.
When asking about semen speed, most males want to know if there is anything they could be doing to affect their sperm motility. There are various behaviors males may partake in that can negatively impact the speed and overall health of their sperm cells. Smoking tobacco, for instance, may be associated with abnormal sperm with low motility. Deficiencies in certain vitamins may also affect sperm's speed.
Certain substances have been tested to determine if they affect “semen speed.” Caffeine, for instance, has been tested and found to increase the speed of male sperm for a temporary amount of time. The exact amount needed may be different for every man. It is not recommended that men drink an unusual amount of caffeine in an effort to improve fertility, as this can have negative affects on health.
If a patient asks a doctor to check their semen speed, they are typically referring to sperm motility. Aside from maintaining a healthy lifestyle by avoiding drugs, and maintaining a healthy weight, there are other factors which may come into play when it comes to male fertility. Certain genetic defects or hormonal conditions may also affect the speed and health of sperm, and are generally checked during an exam.
The exam used to test for sperm motility usually involves having a man ejaculate into a sterile cup. This is accomplished through masturbation which is performed in a fertility clinic. Once the semen has been collected, it is examined under a microscope. The sperm are then visible and a doctor can see if there are misshapen, slow-moving, or dead sperm present.
Many defects can be corrected through surgery or hormonal replacement therapies. Sperm samples may be taken in intervals to test for overall health. The speed of the sperm is not as important as health overall, but since they can only live for a few days once entering the female body, it is important that they move well enough to reach and fertilize an egg.