MMA has a way of aging people prematurely. That's just my observation. I'm no doctor, but it's probably got something to do with getting hit in the face and head a lot, constant heavy-contact training, major repeated weight cuts and so on. It's my gut feeling.

But the sport tends to age some more quickly than others. Here are the five MMA fighters who appear to be aging in dog years.

5. Lloyd Woodard

Let's kick it off with a lesser-known dark horse in Bellator lightweight Lloyd Woodard. The 27-year-old has a brawling style that tends to get him marked up. The horseshoe mustache has an aging effect as well. 

4. Roy Nelson

Speaking of the aging effects of facial hair—yeesh.

The paunchy 37-year-old with the bird's nest beard looks more like a shopping mall Santa Claus on summer vacation than the dangerous UFC heavyweight that he is.

3. Wanderlei Silva

You knew at least a couple of heavy-hitting Brazilians would end up on this list, and few hit as heavily as Wanderlei Silva.

Wandy's take-two-to-give-one style has aged him well beyond his 37 years. It has gotten to the point where his fans wince whenever he takes a shot. However, for better or worse, it doesn't look like he's going to slow down any time soon.

2. Antonio Rodrigo Nogueira

Another 37-year-old going on 50, Antonio Rodrigo Nogueira wears all of his MMA wars on his face. It's clear he's slowing down in and out of the cage, and it's hard to know how many more fights or even training camps he has left in him. 

1. George Sotiropoulos

The UFC lightweight has lost his last two fights by knockout, but his days looking slightly senior predate that. George Sotiropoulos is a jiu-jitsu standout with a legitimate UFC record, but the fact remains that the 36-year-old Australian looks like he's ready for the blue pants and white shoes.

___________________________
Scott Harris is a featured columnist and unrepentant slideshow writer for Bleacher Report. He also likes to talk MMA and other things on Twitter. Find him there @ScottHarrisMMA.