It's a health condition that affects 13.8 million men who are 45 and older, yet less than 10 percent get help even though there is treatment to fix the problem of low testosterone.

"Why men don't go to see the doctor, well you know what, we're in denial," says Dr. Harry Fisch, director of the Male Reproductive Center and urologic microsurgery at Columbia University Medical Center of New York Presbyterian Hospital in New York City.  

But listen to these debilitating symptoms: depressed moods, fatigue and low energy, loss of lean muscle, bone loss, loss of sex drive and erectile dysfunction. Any or all of them can be caused by a low level of the hormone testosterone.

There are also issues related with extreme fatigue when your testosterone is too low in men and women.

"In men, I have to tell you, when testosterone is really, really low people really become couch potatoes they are sitting there with a big belly.  So here's how you know if you have a big belly and you're wearing suspenders good chance you have a low testosterone level," he adds.

Dr. Fisch says it's not only aging that causes men's testosterone to decline.

"It's a biological clock men's testosterone level declines about one percent per year after the age of 30 but still should stay in the normal range, but the biological clock ticks a lot quicker if you have diabetes or are obese or you have a big belly," he says.  

And that's the problem. If you have chronic illness such as diabetes, obesity, especially fat around the mid-section, high blood pressure, high cholesterol or asthma and other lung problems, you are more likely to have low testosterone. And low testosterone just adds to making your health and the way you feel worse.

Men are losing muscle which gives you energy and is the furnace that burns more calories.

"You are so right. That's exactly correct,” said Fisch. “That is testosterone. It actually builds muscle that's been well known so the more muscle you have the more strength you'll have the better glucose control you'll have if you're pre-diabetic you've got to make sure they tell you to exercise and build up muscle because a lot of diabetic men have no upper body strength," explains Dr. Fisch. 

Muscle mass if very important as you get older because it helps keep bone density protecting you from osteoporosis. And doctors say checking your testosterone is as easy as a blood test. And fixing low levels is as easy as getting a prescription gel, tablet, patch or injection.

So if you want to stay younger, fitter make sure you have a normal testosterone level. It will allow you to exercise better and be able to control some of the symptoms of diabetes," says Dr. Fisch. 

Low testosterone has also been correlated with Alzheimer's Disease.