One of the first studies to explore the effects of temperature on sperm quality took a group of men with normal sperm counts and exposed them to heat from a 150-watt light bulb for 30 minutes which raised scrotal temperature by about 5 degrees Fahrenheit for 14 consecutive days. Sperm counts dropped. 12 days later the sperm counts returned to normal. They then iced their balls for 30 minutes for 14 consecutive days, lowering scrotal temperature about 12 degrees. Sperm counts nearly tripled. They then repeated the experiment with men who had low sperm counts. They found a similar pattern but men with lower counts responded less predictably. Some showed little improvement on semen quality, some showed dramatic improvement.