When Alistair Overeem's latest blood test came back after UFC 156, there was a problem, but perhaps not what you would think.

Overeem, the 262-pound heavyweight with the Herculean physique came back with a blood testosterone level reading of 179 nanograms per deciliter, a figure that would be considered dangerously low for a competitive athlete.

While the level seemed shocking to an outsider, one person not surprised was Keith Kizer, the Executive Director of the Nevada State Athletic Commission.

Kizer had ordered Overeem (36-12) to take a blood test and a urine test after his Feb. 2 loss to Antonio "Bigfoot" Silva in Las Vegas. He asked him to take the blood test because it was his first fight back after an unannounced out of competition blood test in late March of 2012 that showed Overeem having taken the steroid testosterone. Overeem later claimed at a hearing before the commission, where he was at the time denied a license, that he did so unknowingly. He said a doctor prescribed an injectable solution to heal a rib injury which contained testosterone causing him to fail the test.

While Overeem was sitting out the nine-month period before he could reapply for a license, one of the things he did was on several occasions provide the Nevada commission with results of both blood and urine tests. In all of those tests taken during periods when he did not have a fight coming, the 32-year-old Overeem blood level reading was consistently in the 180 nanograms per deciliter.

"We would have had a problem if the test came back at 400 (a normal level)," said Kizer. "But it's not happy for him because he has low testosterone."

Overeem's test, taken the morning after the fight, was low enough that most doctors would recommend him to be on a testosterone replacement plan even if he was not an athlete, and would at least in theory, make it very difficult to have the energy to get through a productive training camp or fight at peak efficiency.

But there would be a question, given his previous failure, of him being granted a testosterone use exemption in Nevada.

Nevada's ruling is that if someone's testosterone level is low due to previous steroid use, even though they may need the therapy to live a relatively normal life, the prior cheating excludes them from being able to use it. The subject is controversial because there is no real way to prove what low testosterone came from, whether it was due to usage of steroids, or a different medical issue.

Overeem did seem like a different fighter against Silva. He did not have the aggressiveness he had shown in most of his fights over the previous five years. But he did not appear weak either. While not at the freakish muscular level of some of his fights in Japan where he looked ready to step on a bodybuilding contest stage, he was still very big and powerful looking.

He was still just as heavy, with low body fat, in the fight that he lost via third-round knockout to Antonio "Bigfoot" Silva. He was strong enough to overpower Silva for a takedown and keep him on the ground as well as win the first two rounds against a high-level competitor before a combination of stamina issues and being knocked silly when the two men's heads accidentally collided, led to Silva finishing him.

A reading below 300 would be considered low, and under 250 is low enough to open up risks of an assortment of health problems. Low testosterone leads to a variety of problems, among them diminished aggressiveness, decreased strength, diminished red blood cells (decreasing the oxygen carrying capacity in the blood and causing a decrease in stamina) and overall sluggishness.

These are issues that aren't good for an average person, but would be disastrous for an athlete in a sport that requires the level of training to get through a camp, let alone the conditioning to compete at a high level once a fight begins.

"A competitor with low T levels would most likely not be in optimum condition to fight," wrote Dr. Sherry Wulkan of the New Jersey Athletic Control Board in e-mail correspondence. She noted she was speaking in general terms for athletes with this condition and not specifically regarding Alistair Overeem.

Wulkan said the athletic side effects of low testosterone may not take place at the same time, and that it generally takes longer to lose muscle mass than it takes for a decline in stamina. In other words, a fighter may still look physically impressive and appear to be in great shape, but this condition will make them tire quickly.

There are a few possible causes of low testosterone in a male in their early 30s. Primary hypogonadism, the condition Chael Sonnen claimed to have, is very rare in healthy males. There are drugs or chemotherapy that can lower testosterone production. Steroid use can do so as well, sometimes temporarily, and in some cases, permanently, hence the need for replacement therapy.

Overeem went from being a 205-pound light heavyweight who lost frequently, to looking like a different human being, gaining nearly 60 pounds of competitive weight with no increase in body fat. Due to that, he probably had more suspicion over steroids than nearly any MMA competitor, even before he tested positive the first time he was tested on a date he wasn't told about well in advance.

Overeem had lost five of his last eight fights as a light heavyweight, before moving to heavyweight, where a few years later, many considered him the best in the world. He competed at around 227 pounds early on as a heavyweight, but then rapidly added muscle, seemingly every time he fought, until plateauing at about 262 pounds.

As a big heavyweight, he hadn't lost an MMA fight from 2007 until the loss to Silva earlier this month.