Ah.... Invulnerable Chassis.
You wear it like a vest, it attaches and forms to the skin, and pumps a constant stream of nanobots ((which are protected by a magnetic field so they cant be effected by electricity.))
The nanobots form an armor like layer under the skin that reacts to impacts according to the type. When the body is coming under injury, it reverts the pain into data and blocks it from the brain. The nanobots then repair said injury by creating micro-compounds that mimic tissue, and bond with nerves.
The chassis itself is made from High-carbon steel and reinforced with an artificial diamond compound, and lined with a very thin layer of gold. In between each layer is a thin membrane that nanobots can travel through, and repair the chassis itself. ((by using the damaged steel, diamond and gold thats still part of the chassis.))
The nanobots also act as red and white blood cells, transporting important resources through the body, and protecting it from viral invaders. This means that ageing would almost cease to occur because of the lack of dying cells, due to them all constantly being taken care of.
The chassis and nanobots recharge by either active movement ((which constantly generates a static charge they can charge off of, letting your body itself do most of the work)), food consumption ((the heat generated when digesting food can give the chassis a small boost of energy, as the inner layer would react to heat)), or just the act of sleeping. ((Which gives them time to charge from the process of converting the water you would sweat, which is mostly water, into fuel.))
This means even if you were locking in a room with no light or food, the act of sleeping/staying still would allow you to recharge, until you became dehydrated. But by then, due to your superhuman strength, speed, and agility, you should have found a way OUT of the room.