Research & Education

Lifestyle, A Factor in Fertility?

The profound detrimental effects of chronic stress on fertility and reproductive sex hormone function in both men and women has been highlighted in a previous article. Though stress comes in many forms, the body is unable to differentiate between occupational and lifestyle factors (e.g. inadequate sleep, nutrient depletions, lack of or excessive daily physical activity, exposure to toxins), or stressors as a result of major life events. In the modern world, rarely do we humans experience acute stressors like escaping a major threat, but with our endless to-do lists, and 40+ hour work weeks on top of personal responsibilities, chronic stress seems to be plaguing the population at large with damaging effects to mental, emotional and physiological health.

Not to mention, the busier and more stressed people become, the less attention is given to maintaining health-conscious behaviors such as eating a diet rich in plant-based whole foods, finding daily movement, and practicing regular self-care. No matter the stimulus, over time chronic stress wreaks havoc on the body’s physiology; too much of it may manifest in serious health conditions that inhibit reproductive function.

The Link between Insulin Resistance, Obesity, and Infertility

Healthy blood sugar levels is a major contributing factor in maintaining proper reproductive function. Proper blood sugar levels and a healthy weight reduces the risk of developing metabolic-related diseases associated with infertility such as type 2 diabetes, metabolic syndrome, obesity, and polycystic ovarian syndrome (PCOS). All of which are linked by a common determinant: insulin resistance, which is caused by chronically elevated blood sugar.

In a mini-review published in 2018, obesity was labeled “an enemy of male fertility”. Excessive body fat leads to increased aromatization and leptin levels which disturbs the hypothalamic-pituitary-gonadal (HPG) axis by decreasing testosterone production from the Leydig cells of the testes. Moreover, excess adipose tissue is correlated with increased pro-inflammatory cytokine production (and reactive oxygen species) altering spermatogenesis and causing DNA damage to sperm. A study in the journal Andrology shows that low circulating testosterone and secondary hypogonadism is linked with insulin resistance and low ejaculate volume in obese males with higher BMI and excess body weight. Other commonly associated mechanisms linking obesity with infertility in males is erectile dysfunction, obstructive sleep apnea, hyperthermia, chronic epididymitis, and epigenetic changes.

A narrative review published earlier this year explains the impact that metabolic syndrome has on female sexual dysfunction. Compared to those without metabolic syndrome, women with diabetes, hypertension, and dyslipidemia showed a higher predominance towards sexual inactivity and lower libido.

Sleep: A Non-Negotiable for Healthy Sexual Function

The quality and quantity of sleep is another critically important factor in healthy fertility. A recent prospective preconception cohort study in the journal of Fertility and Sterility evaluated the association between male sleep duration and fecundability among couples who had been trying to conceive for less than or equal to six cycles and found that short sleep duration (<6 hours per night) is related to lower fertility. The study reported that those sleeping between seven and nine hours per night had the lowest risk of adverse health outcomes and that sleep quality is positively correlated with testosterone levels as most of the hormone released occurs during the sleep. Sleep deprivation is linked with declining sperm count and lower semen parameters. The Journal of Clinical Sleep Medicine found a positive linear relationship between sleep duration and testicular volume as well as rapid eye movement (REM) sleep and follicle-stimulating hormone in males. Sleep disturbances were shown to dysregulate levels of TSH, LH, prolactin, testosterone, estradiol, progesterone, and anti-Mullerian hormone (a marker of ovarian reserve), which interferes with the multifactorial processes involved in reproduction.

Shift Work and Altered Fertility

According to a multi-center, cross-sectional study, females of reproductive age working the night shift are at greater risk for metabolic syndrome compared to daytime workers. As mentioned earlier, those with metabolic syndrome are at an increased risk of sexual dysfunction. Shift work is associated with dysmenorrhea, irregular periods, and increased time to pregnancy. Compared with non-shift workers, infertility rates were greater among shift workers. Fecundity rates in nurses planning pregnancy from the third cohort of the Nurses’ Health Study were analyzed based on work schedules and physical factors. The results of the study showed that women who worked more than 40 hours per week and those with greater frequency of heavy lifting or moving heavy loads had reduced fertility outcomes and increased time to pregnancy. 

Radiofrequency and Electromagnetic Fields on Reproductive Function

With the increasing use of electronic devices like mobile phones, laptops, and gaming devices, there is an inevitable rise in the electromagnetic field (EMF) exposure. A review published in Oxidative Medicine and Cellular Longevity compiled compelling evidence revealing the deleterious effects EMF exposure has on mitochondrial functionality, specifically by influencing the production of reactive oxygen species which pose threat to the reproductive organs in both females and males by way of disrupting the HPG axis. Another review exploring the effects of radiofrequency (RF) radiation on male fertility patterns concluded that in addition to RF-EMF exposure negatively affecting metabolic and endocrine system enzyme function, producing genotoxicity and oxidative stress, that it has harmful effects on sperm count, morphology, and motility. 

Healthy Habits to Combat Infertility

Patients may seek help from their licensed healthcare practitioners to learn more ways to prevent these issues before they occur. Most of the causative factors mentioned are often preventable and reversible with lifestyle and dietary modifications. Identifying and addressing modifiable factors of infertility would provide alternatives to costly fertility treatments. Educating patients who are trying to conceive may find it beneficial to avoid exposure to toxins such as cigarette smoke, alcohol, recreational drugs, prescription medications, and EMFs while implementing healthy behaviors such as consuming a diet rich in antioxidants and low in processed foods, managing stress levels, and getting adequate sleep.