Erectile dysfunction (ED) is mostly addressed as a psychogenic disorder, but an organic form of ED occurs in about 10-15% of all cases1 and in 72% of cases in men under the age of 40 years.2 The organic cause of ED is strongly linked to low testosterone levels as well as atherosclerosis and cardiovascular disease (CVD). ED is typically age-related with many similar risk factors to CVD including hypertension, diabetes, smoking, obesity, dyslipidemia.3 In the Massachusetts Male Aging Study (MMAS), 1057 men aged 40-70 years who did not have CVD or diabetes at baseline were followed for roughly 10-13 years.4
Sperm health isn’t typically on men’s radar unless they have been experiencing difficultly conceiving with their partner. Many men, unlike women, tend not to change many lifestyle or dietary factors when trying to conceive. Therefore many continue to drink, smoke, have poor sleep habits, or maintain a high body fat percentage at the beginning of the fertility journey. These factors have been associated with sexual and reproductive dysfunction including decreased libido, erectile dysfunction, and ejaculation issues.1
What most men don’t know is that spontaneous genetic mutations arise more often in the father’s germ cell line and are majorly influenced by environmental and lifestyle factors. Sperm DNA health will then directly affect the health of the offspring – and prior to that will affect the ability of a fertilized embryo to survive. Higher DNA fragmentation of sperm cells is a cause of infertility as it decreases sperm quality, which can lead to increased rates of miscarriage.2
Even for men not looking to produce children, parameters of sperm health and quality can be indicators of chronic health. Physical and lifestyle factors can easily be modified and addressed to improve ejaculation volume, sperm quality and can help keep sex hormones such as testosterone in normal physiological levels.
For men, alcohol consumption is associated with poor sperm production and function, and has been linked to testicular atrophy, decreased semen volume and lower libido.3 Of those who have a daily drink (even one beer), 33% have moderately decreased sperm production, and therefore low sperm counts.4 The good news is that this effect is reversible when alcohol consumption ceases.
Smoking tobacco has been associated with low sperm counts – even if the individual is otherwise healthy. Cigarette smoke contains toxic chemicals that can cause DNA mutations, cell death and decreased development of sperm cells. It can also introduce lead into seminal fluid and increases carbon monoxide levels, which decreases oxygen levels within the testes.4
One in vitro study suggests that cigarette smoking may reduce the mitochondrial activity in spermatozoa, and lead to a decreased fertilization capacity.5 Hormone function may also be affected as studies report higher serum levels of certain hormones and decreased concentrations of testosterone in men who smoke.3
The use of marijuana is fairly common and perhaps more so with the introduction of its legal use (both medically and recreationally) in many states and provinces in North America. Although there are many positive benefits to marijuana-based treatments for specific ailments such as pain, anxiety and inflammation, it’s chronic use is associated with dramatically decreased testosterone levels and a noticeable decrease in sperm motility, viability and function.4 In men, it’s been reported that cannabinoids can reduce testosterone production and decrease sperm origin, development and motility.3
Phthalates are a group of chemicals and plasticizers used in food processing and packaging, in personal body products, fragranced products, and mosquito repellants. Phthalates seem to be more problematic for men than women in their reproductive effects. Phthalates increase oxidative stress which damages sperm and sperm DNA. It can also block testosterone and increase the risk of insulin resistance and diabetes.
One study found that phthalate concentrations in men were associated with a 20% decrease in incidence of positive pregnancy in couples trying to conceive.6 The majority of our exposure to phthalates comes from dietary consumption including beef, pork, cooking oils and cheese.6 Exposure can be decreased by avoiding processed foods and limiting those in plastic packaging; as well as limiting use of personal hygiene products that contain parfum/perfume or chemical fragrances.
Obesity and Physical Activity
Obesity affects sexual performance and function, but also sperm count and quality. Body fat is storage tissue and in excess can exert hormonal effects, specifically with testosterone, estrogen and insulin. A high body-mass index (BMI) has been associated with lower ejaculate volume, decreased sperm concentrations and sperm quality.7
Hormone imbalance can be a side effect of excess body fat which can lead to abnormally increased estrogen levels and a lower testosterone-to-estrogen ratio.3
One study showed that men who had a baseline BMI of 33 to 61 kg/m2 had significantly lower sperm counts, lower motile sperm and fewer structurally normal sperm. They also had significantly lower testosterone levels and higher estradiol levels.8
When the men in the above study underwent a 14 week weight loss regimen consisting of dietary changes and physical activity, resulting in a median weight loss of about 15%, there was a significant increase in total sperm count, semen volume and testosterone levels. The group that lost the most amount of weight had significantly increased total sperm counts and increased percent of sperm with normal morphology.
Higher rates of DNA fragmentation have also been reported in men who are obese which is one cause of abnormal sperm parameters and less successful IVF cycles. Abnormal sperm has also been associated with up to an increased risk of testicular cancer.7
Supporting a healthy weight for sperm and testicular health starts with a healthy diet high in vegetables and antioxidant-containing fruits, and minimal amounts of processed foods and trans fats. Regular physical activity also plays a major role both in weight management but also in fertility in general.
However, men should be mindful of activities that can negatively affect testicular health. For example, those who ride bicycles regularly and for long durations have an increased risk of testicular injury. Bruising, chaffing and damage to hair follicles are common among male cyclists, and cycling for more than five hours per week has been negatively correlated with total motile sperm counts and sperm concentration.3
This isn’t meant to deter men from exercising or biking, however, it’s important to be mindful of testicular safety by reducing or avoiding physical impact to the testicles and extensive heat exposure. Therefore certain activities should be modified when necessary. For example, cyclists should limit weekly hours spent on a bicycle saddle, try to take frequent breaks and try not to sit continuously.
Overall, sperm health and quality are associated with chronic health in men. Lifestyle factors and exposures are major influencers and can be modifiable to improve testicular and sperm health in as little as three to six months. Although many men may not be trying to conceive with their partner, these factors are still important as they influence sexual function and performance, and changes in sex hormones such as estradiol and testosterone can affect many other areas of men’s health including mood, libido, energy, strength and endurance.
- O’Brien AP, Hurley J, Linsley P, et al. (2018). Men’s preconception health: a primary health-care viewpoint. Am J Mens Health. 12(5): 1575-81
- Esteves SC. (2016). Novel concepts in male factor infertility: clinical and laboratory perspectives. J Assist Reprod Genet. 33(10): 1319-35
- Sharma R, Biedenharn KR Fedor JM Agarwal A. (2013). Lifestyle factors and reproductive health: taking control of your fertility. Reprod Biol Endocrinol. 11:66
- Gabrielsen JS and Tanrikut C. (2016). Chronic exposures and male fertility: the impacts of environment, diet and drug use on spermatogenesis. Andrology. 4(4): 648-61
- Calogero A, Polosa R, Perdichizzi A, et al. (2009) Cigarette smoke extract immobilizes human spermatozoa and induces sperm apoptosis. Reprod Biomed Online. 19(4): 564-71
- Buck Louis GM, Sundaram R, Sweeney AM, et al. (2014). Urinary bisphenol A, phthalates, and couple fecundity: the Longitudinal Investigation of Fertility and the Environment (LIFE) study. Fertil Steril. 101(5): 1359-66
- Fainberg J and Kashanian JA. (2019). Recent advances in understanding and managing male infertility. F1000Res. 8:F1000 Faculty Rev-670. doi: 10.12688/f1000research.17076.1.
- Hakonsen LB, Thulstrup AM, Aggerholm AS, et al. (2011). Does weight loss improve semen quality and reproductive hormones? Results from a cohort of severely obese men. Reprod Health. 8:24
- Meachem SJ, Nieschlag E, Simoni M. (2001). Inhibin B in male reproduction: pathophysiology and clinical relevance. Eur J Endocrinol. 145(5): 561-71