Your Semen Analysis: Sperm Vitality

In its simplest form, sperm vitality is basically the percentage of living, healthy sperm in your semen. It’s important to think of each sperm cell is a living thing, with an ability to move on its own and its own lifespan. In your testicles, these little guys have a lifespan of around 72 days. Once a sperm cell dies, it remains in the testicles for time and the body begins to break it down and reabsorb it.

Vitality. It sounds like something out of a denture commercial, something you see on vitamins and in health food aisles. A quick google will tell you that vitality is “1) the state of being strong and active; energy. 2) the power giving continuance of life, present in all living things.”  But sperm vitality is a whole different ball game (no pun intended). Also known as viability, sperm vitality is actually a crucial measurement of your fertility. So what is vitality, and why is it so important?

What is sperm vitality?

In its simplest form, sperm vitality is basically the percentage of living, healthy sperm in your semen. It’s important to think of each sperm cell is a living thing, with an ability to move on its own and its own lifespan. In your testicles, these little guys have a lifespan of around 72 days. Once a sperm cell dies, it remains in the testicles for time and the body begins to break it down and reabsorb it.

Here’s where people get confused: sperm vitality is not the same thing as motility. While sperm vitality definitely contributes to motility- if sperm are dead, they’re definitely not swimming- these two parameters measure very different things. Motility measures how many sperm are swimming and their swimming prowess, while vitality is a measurement of all living sperm-whether they’re moving or not.

What’s a normal sperm vitality level?

Since it takes time for dead sperm cells to be broken down and reabsorbed, there are bound to be a few dead sperm cells in your semen at any given time, which means that a sperm vitality percentage of 100% is incredibly rare. The WHO defines the average sperm vitality range as 58-91%.

What causes low sperm vitality?

Heat Exposure: Sperm require a very specific temperature (roughly 4 degrees cooler than boy temperature) to survive. This means that exposure to higher temperatures for prolonged periods of time cause your sperm to overheat and die, tanking your vitality percentage. For more information, check out our article on heat and male fertility.

Obesity: Obesity adds an extra layer of insulation to your body, exposing sperm cells to deadly high temperatures. Obesity also throws your hormones off-balance, impacting the production of new, healthy sperm. For more information, read our article on obesity’s impact on your fertility.

Toxin Exposure: First, let’s clarify what we mean by toxins. We define toxins as not just environmental factors, like exposure to pesticides, radiation, heavy metals (like the lead found in solder) or cleaning solvents. Toxins also include things like cigarette smoke, marijuana and alcohol. All of these factors effectively kill cells, particularly the sensitive sperm cells. Learn more about what a toxin is and what it does to your sperm.

Necrospermia

It’s a big word, we know. But it’s one with a pretty simple meaning. Necrospermia (also known as necrozoospermia) is a condition in which there are no living or motile sperm in your semen. While it can occasionally be caused by lifestyle factors, such as certain prescription drugs, necrospermia is most often caused by hormonal imbalances, plumbing problems, and autoimmune disorders.

How is it tested?

A vitality test is usually ordered after an initial semen analysis comes back with a motility percentage of under 25%. The real trick to testing for sperm vitality is to find out which sperm are just alive and not moving and which sperm are completely dead. This test is performed by using a special technique called eosin-nigrosin staining. It involves applying a dye to a sample and examining it under a microscope. The theory behind this is that live sperm have a barrier that prevents dye absorption, while dead sperm can’t resist the dye, so they get stained a light pink. The sperm are then counted and the percentage of live sperm is taken.

How can you improve sperm vitality?

Improving your sperm vitality can be as easy as making a few simple lifestyle changes. In general, a healthier, vitamin rich diet, and a limit to heat and toxin exposure can help naturally improve your sperm vitality. You can also get specific tips for how to improve your sperm vitality by taking our Risk Assessment Quiz.