The T-800 famously continually reminded us that he'd "be back," and it was a promise he's kept longer than we thought. However, each time the Terminator returns to the screen, he looks a little worse for wear, especially in Terminator: Genisys.
When Arnold Schwarzenegger announced he was returning to the Terminator franchise, the screenwriters had to think up a nifty way to explain why a time-traveling robot from the future now looked like a 67-year-old former governor.
To do this they dug up a line first stated in Terminator 2: Judgement Day (and then remixed into a metal song by band Austrian Death machine) which lays down the fundamentals of what the T-800 actually is. In T2, Arnie states:
"I'm a cybernetic organism. Living tissue over a metal endoskeleton."
According to Terminator: Genisys screenwriters Laeta Kalogridis and Patrick Lussier, this simple fact explains how the Terminator has seemingly aged. His skin is actually living skin which is subject to the same aging processes as ours. However, the Nerdist didn't seem happy with this explanation, as they recently posted up a new video investigating whether putting "living tissue over a metal endoskeleton" would actually work.
What Does Skin Need to Survive?
According to the Nerdist, time-traveling in the Terminator universe only works if the subject is covered in organic material. Of course, this explains why everyone appears to arrive from the future dressed only in their birthday suits, although it doesn't seem to explain how the shapeshifting T-1000 (who is made of a mimetic poly-alloy) can time-travel - but maybe we shouldn't get bogged down on that.
Anyway, for the T-800 to time-travel, he would need to be covered in about 2 square meters of skin, which would have to be provided with some kind of blood supply to stop it from instantly decaying. Furthermore, for long-term survival/infiltration, the skin would also have to be provided with nutrients and water to prevent it from dying.
So, do the movies suggest this is the case? Well, at various points in the franchise we see the Terminator sweat and bleed (although not profusely), which suggests there is a blood supply connected to the Terminator's tissue. In Terminator 2, Sarah Conner also learns that the Terminator can heal wounds, which would require nutrients and other organic resources to accomplish.
Watch the T-800 repair himself in the Terminator clip below:
The Nerdist therefore concludes that the Terminators likely only age extrinsically thanks to the influence of weathering, physical damage and pollutants in the air. However, they do not age intrinsically like humans, since this is based on biological factors such as disease, genetics and a reduction in collagen production.
How Much of the Terminator Is 'Living'?
So, does the Terminator actually need to eat and drink to preserve the state of its living tissue? This seems unlikely from watching the movies, although there might be another answer hidden elsewhere in the franchise.
Within the original script for James Cameron's The Terminator, there were some lines which better explain the construction of the T-800, but they were eventually cut from the movie. They did, however, make their way into the novelization of the first film, and were spoken by Kyle Reese. He explains:
"Cybernetic organism. A machine put together with a living thing. The skin and some layers underneath it, the hair, the surface of the eyes, the inside of the mouth. All that stuff's human tissue genetically designed for the cyborgs. It has to eat and breath to keep the skin alive, though a lot less than us. And there's a little tiny heart and internal organs about the size of a chicken's in a recessed compartment."
So in reality, there is a lot more going on with the Terminator than meets the eye. It's probably safe to assume that damaging these internal organs is not fatal to the Terminator, although it would most likely lead to the decay and destruction of its living tissue 'disguise.'
So, although the Terminator has little to fear from bullets, helicopter crashes and biker gangs, even he probably still has to moisturize.