Each sperm produced by the testes takes about seventy-two days to mature and its maturity is overseen by a complex interaction of hormones. The scrotum has a built-in thermostat that keeps the testes and sperm at the correct temperature. It may be surprising that the testes should lie in such a vulnerable place outside the body, but it is too hot for them inside. Spermatogenesis requires a temperature that is three to five degrees Fahrenheit below body temperature. If it becomes too cool on the outside, the cremaster muscle will contract to bring the testes closer the body for warmth.
"Every man desires to live long," wrote Jonathan Swift, "but no man would be old." He was right, but the fountain of youth has proved illusory. And while more study is needed, GH does not appear to be either safe or effective for young athletes or healthy older men. But that doesn't mean you have to sit back and let Father Time peck away at you. Instead, use the time-tested combination of diet and exercise. Aim for a moderate protein intake of about .36 grams per pound of body weight; even big men don't need more than 65 grams (about 2 ounces) a day, though athletes and men recovering from illnesses or surgery might do well with about 20% more. Plan a balanced exercise regimen; aim for at least 30 minutes of moderate exercise, such as walking, a day, and be sure to add strength training two to three times a week to build muscle mass and strength. You'll reduce your risk of many chronic illnesses, enhance your vigor and enjoyment of life, and — it's true — slow the tick of the clock.