By Kenneth Harper Finton

Man looking in his underwear
Does the penis shrink in size as it ages? The astounding answer is “yes, it does.” Nobody talks about it. Men fear it, women don’t really care, and young men have no idea what is coming (pun intended). Sexual dysfunction in men with age is no secret. Sometimes it seems that every other ad on TV tries to sell a pill for it. Newer comedy movies are not complete until the older male has a problem with his little blue pill that leads to hilarious consequences. The percentage of potent men falls from 60% to around 30% between the ages of 40 and 70.
Most men know little about their penis. It begins to change around age 30. The head gradually loses its purplish color that is created by healthy and youthful blood flow. The head becomes less sensitive and gradually shrinks in size and girth as a result of decreased testosterone and blood flow. By the time a man is 60 or 70 he loses around an inch or more in size.
“If a man’s erect penis is 6 inches long when he is in his 30s, it might be 5 or 5-and-a-half inches when he reaches his 60s or 70s,” Irwin Goldstein says. “As testosterone wanes, the penis gradually reverts to its prepubertal, mostly hairless, state.” Goldstein, MD, is director of sexual medicine at Alvarado Hospital in San Diego and editor-in-chief of The Journal of Sexual Medicine. So even men without a tendency for baldness should not be surprised that they also gradually lose pubic hair. It also turns gray as it thins. [If this fact is troublesome, one alternative would be to shave it off like porno stars do and lengthen the apparent length of your penis as well.]
Age brings declines in semen volume and sperm quality. Also, the urine stream weakens as the bladder muscles become weaker and the prostate enlarges.
The beer belly adds to the apparent loss in size of the penis because “a large pre-pubic pad of fat makes the penile shaft look shorter,” says Ira Sharlip, MD, clinical professor of urology at the University of California, San Francisco.
“In some cases, abdominal fat all but buries the penis,” says Ronald Tamler, MD, Ph.D., co-director of the Men’s Health Program at Mount Sinai Hospital in New York City. “One way I motivate my overweight patients is by telling them that they can appear to gain up to an inch in size simply by losing weight.”
The penis shrinks from the same process that causes atherosclerosis. It is the same disease that contributes to blockages inside the coronary arteries and is a leading cause of heart attack. Fatty plaque is deposited by the blood in the small arteries and vessels in the penis, impairing the flow of blood and making erections softer and harder to achieve.
USE IT OR LOSE IT

overripe banana
You need to have erections regularly to keep your penis in shape. “It has to be essentially exercised,” says Tobias Kohler, MD, assistant professor of urology at Southern Illinois University School of Medicine.
The brain dreams and dreams help to set up an automatic penis maintenance function for exercising the penis. “Pulses from the brain cause erections during the dreaming phase of sleep called the REM phase.”
Whether by a remembered dream or not, the penis gets hard during that REM period of the sleep cycle. It doesn’t matter if you’re having a hot sex dream or an apocalyptic nightmare. Dreaming brings erections.
Some men such as those who’ve suffered trauma to the nerves involved or who have nerve or blood vessel damage caused by diabetes are physically unable to get erections.
Most men can get erections.
There is a lot of locker-room significance to the facts. You cannot assume that a man with a big, limp penis gets much bigger with an erection. The guy whose penis looks tiny might get a surprisingly big erection. Many women do not care about penis size, as enormous shafts can be quite painful. If a finger works for satisfaction, a smaller penis can also suffice as well. Technique is often more important than size. Half the total length of a penis is tucked away inside the body. It is invisible.
“It’s what he does with it and the rest of his body that matters,” says Lou Paget, a certified AASECT sex educator and author of “The Great Lover Playbook.”
SOURCES:
http://www.webmd.com/men/guide/life-cycle-of-a-penis
http://www.huffingtonpost.com/2015/01/15/penis-problems-aging-_n_6480920.html
http://www.webmd.com/men/guide/8-things-you-did-not-know-about-your-penis
http://www.menshealth.com/health/your-penis-when-you-age