By Ruby Austen, a Crankstart Scholar and Biologist at St. Anne's College, University of Oxford.
There are are a number of factors which determine sperm health, including volume, shape and motility. Many studies have emphasised the importance of this third trait – motility, including in the global standards from the World Health Organisation’s guidelines for semen analysis (1). Our overview of male fertility testing can be found here, if you're curious!
What is sperm motility?
Sperm motility is the ability of a sperm to move (or “swim”) properly to reach an egg. Motility can therefore be assessed and used as a measure of sperm quality, since sperm that do not swim properly will not be able to reach the egg in order to fertilize it (2).
For sperm to do this, they should have a trait called ‘progressive motility’, which means that they are swimming in a mostly straight line or in large circles (3).
Sperm can be sorted into into 4 levels of motility, with the ideal, healthy sperm having ‘rapid progressive motility’ essentially meaning that sperm are moving actively and at a good speed, and the lower end being ‘immotile’ where the sperm have no active movement (1).
What causes poor sperm motility?
If a person with sperm has poor sperm motility, it’s known as ‘Asthenospermia’ and ranges from slow, sluggish movement to no movement at all (4).
There are a number of risk factors which may cause this, including both genetic abnormalities and lifestyle/environmental factors.
Lifestyle choices which have been associated with reduced sperm motility include;
Smoking and drug use
Drinking alcohol
High BMI (or being overweight)
Meat consumption
Lack of sleep
Prolonged cell phone & laptop use (3).
Does my age impact sperm motility?
It's well known that trying to have a baby later on in life can make it trickier for couples to become parents, with strong evidence showing that there is a significant decrease in sperm motility and concentration with increasing paternal age (5). This is because, like all cells in our body, sperm cells are impacted by aging and experience degradation – so it is entirely normal for this to happen (6).
However, there are many examples of older men have been able overcome this including celebrities who made headlines – take Simon Cowell who had a baby at 54, or Robert De Niro at 79! (8)
So, what is hidden below the surface that may be influencing fertility here? There’s good evidence that factors such as hormones changes (particularly testosterone) and oxidative stress (which can cause DNA damage in sperm) have an impact that can be improved naturally (7). While they can be managed with lifestyle choices, it should be noted that these processes also occur regardless of good health and happen through normal bodily processes.
There are also some risks potentially associated with conceiving at a later age, including late stillbirths, preterm births and structural or neurological abnormalities in offspring. However, the research in this area is mixed, with some studies suggesting there is a correlation and others suggesting no correlation at all. In any case, it is important for parents to be aware of these possible risks (8).
How to improve sperm motility
Since a large contributor to sperm immobility is lifestyle, there is a lot you can do to improve sperm motility and sperm health overall! Healthy lifestyle changes are a good first step to improving motility considerably and improving your fertility.
This may include:
Consuming a more balanced and nutritious diet
Participating in regular exercise
Quitting smoking
Reducing your alcohol consumption (9).
While a nutritious diet has been shown to be effective, there is evidence that some supplements can also be taken to significantly improve sperm motility. For example, a supplement called ‘carnitine’ is a compound made naturally in the body for turning fat into energy, but it has also been found to improve sperm motility.
Additionally, it has been found that supplements such as ‘CoQ10’ and ‘alpha-tocopherol’ significantly improve sperm count, and vitamins E and C can reduce sperm DNA damage. However, it is essential that you consult a doctor before taking any supplements to ensure they are safe for you and are purchased from a reputable source (10).
Finally, you may also choose to have a semen analysis, which is a very useful way to check the quality and quantity of the sperm. This will allow you to determine whether further action with assistance from your GP who can refer you to a specialist if any problems are found (11).
References
1. World Health Organization. WHO laboratory manual for the examination and processing of human semen. 6th ed. Geneva: World Health Organization, Cop; 2021.
2. Hardy D. Fertilization. San Diego, Calif. ; London: Harcourt Academic; 2002.
3. Dcunha R, Hussein RS, Ananda H, Kumari S, Adiga SK, Kannan N, et al. Current Insights and Latest Updates in Sperm Motility and Associated Applications in Assisted Reproduction. Reproductive Sciences. 2020 Dec 7;29(1).
4. Sperm Motility: Causes, Treatment, and More [Internet]. Healthline. 2023. Available from: https://www.healthline.com/health/fertility/sperm-motility
5. Collodel G, Ferretti F, Masini M, Gualtieri G, Moretti E. Influence of age on sperm characteristics evaluated by light and electron microscopies. Scientific Reports [Internet]. 2021 Mar 2 [cited 2021 Dec 6];11(1):4989. Available from: https://www.nature.com/articles/s41598-021-84051-w
6. Mazur DJ, Lipshultz LI. Infertility in the Aging Male. Current Urology Reports. 2018 May 17;19(7).
7. Nguyen-Powanda P, Robaire B. Oxidative Stress and Reproductive Function in the Aging Male. Biology. 2020 Sep 11;9(9):282.
8. Test Him. age and male fertility [Internet]. testhim.com. Available from:
9. Anderson K, Nisenblat V, Norman R. Lifestyle factors in people seeking infertility treatment - A review. Australian and New Zealand Journal of Obstetrics and Gynaecology. 2010 Feb;50(1):8–20.
10. Ahmadi S, Bashiri R, Ghadiri-Anari A, Nadjarzadeh A. Antioxidant supplements and semen parameters: An evidence based review. International journal of reproductive biomedicine [Internet]. 2016;14(12):729–36. Available from:
11. NHS Choices. Low sperm count [Internet]. NHS. 2019. Available from: