Many lifestyle factors are associated with male fertility. There is a link between smoking and poorer semen quality, but the impact on the male’s fertility is uncertain. Similarly, excessive alcohol consumption (above the recommended limit of 3 to 4 units of alcohol per day) can impair semen quality, although alcohol consumption below this level is unlikely to affect fertility.¹

A stressful or sedentary lifestyle, and ageing, can also reduce male fertility. It is not clear if reducing caffeine helps improve fertility, but there may be more of an association with infertility if caffeinated beverages are sweetened.^1,4

Conversely, a healthy diet is associated with better sperm quality including higher sperm count, concentration and motility and lower sperm DNA fragmentation. Men with infertility problems should therefore be given healthy lifestyle advice including exercising and eating healthily.^4,5

Occupational risks affecting fertility include exposure to X-rays, pesticides, or heavy metals such as cadmium and lead. Radiotherapy to the pelvic area, pituitary gland or total body irradiation can impair fertility.^1,4,6

While higher scrotal temperatures can reduce semen quality and impair sperm production, it is not clear whether wearing loose-fitting underwear has any effect on improving fertility.¹