There are a number of lifestyle factors that can cause DNA fragmentation:
Heat: Heat can cause increased testicular temperature, which negatively affects spermatogenesis, i.e. sperm formation and development. The temperature in the testicles is usually around 2°C lower than in the rest of the body, so that the sperm can develop optimally. Sperm DNA fragmentation has been observed in animal studies where testicular temperature was at or above body temperature. What can you do? First, your doctor may recommend wearing loose underwear, such as boxer shorts, rather than briefs.
Laptop computers: They generate a lot of heat and can damage sperm DNA if left on the lap for long periods of time. Put something between your lap and the laptop.
Hot Tubs : Hot tub temperatures are higher than body temperature. Baths in it should be avoided during attempts to conceive. Also, avoid taking long, hot baths.
Obesity: Overhanging abdominal fat causes heat trapping, which can lead to sperm DNA damage. When sitting, you can put an air seat cushion on top of your seat pad/chair etc. (often used by long haul truckers). Thus, the testicles are close to the “air cooling pad”.
Diet: Eating a balanced diet of whole foods packed with vitamins and minerals is important for both women and men and should be part of your TTC plan.
Clinical Study for Lifestyle
To mimic elevated testicular temperatures caused by clothing, for example, a bull’s testicles were placed in a woolen sock for 48 hours. Elevated scrotal temperature adversely affected both epididymal and testicular sperm, as evidenced by a doubling of %DFI (4% to 8%) within three days. After 12 days, a 5-fold increase in %DFI was observed. Interestingly, the sperm showed a significant presence of nuclear vacuoles 12 days after the stressor. (Karabinus et al. (1997) J Androl 18:549-555.
Mouse body temperature is around 37°C. Placing mice in a heated water bath so that only the testicles are exposed to the high temperature, slight effects on sperm DNA are observed after 1 hour at 38°C. Even 3 days at elevated temperatures has little effect on sperm DNA fragmentation. However, an increase in temperature from just 2°C to 40°C caused a doubling of the %DFI and a tripling of the %DFI by day 14. Testicular weight did not decrease after 35 days. Therefore, the damage from what appeared to be a minor exposure to heat caused very significant sperm DNA fragmentation. Studies clearly show the negative effects that excessive heat can have on the testicles/episodes and therefore on sperm.
Sailer et al. (1997) J Andrology 18:294-301