You must rest!
This is because while watching tv your brain is working and your body rests. The thing is to let your brain rest for a while. Good ways to rest are for example yoga, Pilates, relaxation or meditation cd’s.
Rest is a time for your thoughts and autonomic nervous system. Rest is quiet time for your brain, a couple of minutes of silence.

Time when your thoughts stop for a second and you breathe deep.
Your energy level rises more when you spend a couple of minutes in quietness than when resting hours at a sofa while watching tv.

This is because while watching tv your brain is working and your body rests.
The thing is to let your brain rest for a while.