Eating a healthy and balanced diet is a key part of maintaining good overall sexual health. Consuming a diet high in fish, fruits, vegetables and antioxidants has been shown to improve semen quality. Whereas diets which have high amounts of caffeine, fat, protein and processed food appear to have a negative impact [16]. Being overweight or underweight has also been found to worsen sperm quality [5]. Obese men who improve their diet and take part in regular exercise can significantly improve their chances of fathering a child [8]. Men who exercise at least three times per week for over an hour at a time have improved sperm quality [18]. However, excessive exercise or lack of exercise has the opposite effect [22].

Several substances have been shown to adversely affect sperm production and function, including; cigarette smoking, alcohol, marijuana and anabolic steroids [2]. Men who smoke tend to have a reduction in their sperm count, semen volume, density and motility. These effects, however, can be reversed following smoking cessation for over 3 months or longer [14]. Alcohol is also a recognized testicular toxin with its effects being dose and duration dependent [4]. A number of studies have shown that stopping alcohol consumption can lead to rapid and dramatic improvement in semen characteristics [20]. Staying within the recommended alcohol intake for men does not appear to reduce sperm quality or function.

Anabolic steroids are increasingly being used by young men in their reproductive years who are unaware of the consequences associated with their misuse. Anabolic steroids suppress sperm production and reduce sexual drive by decreasing testicular testosterone levels [6]. These effects are usually reversible but it can take up to 3 years to regain function [2]. Some prescription medications such as opioids, antidepressant and anti-epileptics can also reduce sperm quality [18].

The use of illegal drugs is common in peak reproductive age groups with marijuana being one of the most commonly used drugs worldwide. It misuse has been shown to reduce testosterone levels as well as sperm production and function [3]. Another large group of illicit drugs which impair testicular function are opiates, such as heroin and methadone [17]. Men taking these drugs reported sexual dysfunction with these effects persisting even after cessation [21]. Cocaine is also commonly used as a recreational drug with long term male users reporting it harder to maintain an erection and to ejaculate [9]. Men with sub-fertility who use illegal drugs will improve their chances of fathering a child if they quit and should seek medical advice for the appropriate support if required.

Stress due to psychological, physical or social reasons is unfortunately a common and prominent part of our society. Being stressed can affect a man’s libido and semen quality [10]. Taking time to relax and unwind can boost libido, sperm quality and increase changes of a pregnancy [2].

The testicles are located within the scrotum to maintain their temperature a few degrees below core body temperature for optimum function. A number of studies have shown that increased testicular temperature decreases sperm quality with these effects being reversed by cooling [1, 19]. Having hot baths or regular sauna use; wearing tight under wear or restrictive clothing; prolonged sitting or driving; and using portable computers on their laps are possible contributory factors which sub-fertile men should try to avoid [19].

There has been a rapid rise over the past decade in the use of mobile telephones and other electronic devices with the long term effects on human health from exposure to radio-frequency electromagnetic radiation yet to be determined. Several studies have shown a decrease in sperm quality and function in men who use electronic devices on a regular basis [1, 11]. In addition, these effects appeared to be dependent on the duration of mobile phone possession and the frequency and length of telephone conversations [12]. Men who carry their mobile phone in their trouser pockets or on their belts have been shown to display poorer semen function compared to those who keep them elsewhere [13]. Sub-fertile men can help boost their reproductive potential by attempting to reduce their use and contact with these devices.

Sub-fertile men should be aware of the potential hazards they are being exposed to in their working environments. Regular exposure to heavy metals, chemicals, pesticides and poor air quality can have a negative impact on reproductive health by interrupting the hormonal pathways involved in sperm production and reducing libido [4, 18]. Sub-fertile men should strive to minimize their exposure to these materials and take the appropriate precautions whilst at work (Table 26.2). It is also important to recognize that exposure to these materials can occur during hobbies, such as; gardening or craft work and therefore similar preventive measures should be taken at home.