This unfortunately ruined reading for me for a long time. I associated reading with sleep, and it became a pavlovian response: a few pages in, any time of day under any circumstances, I'd start to nod off.
This is easy to fix. Just spend at least as much time reading on a treadmill or other exercise device as you do before bed and you will learn to discriminate very quickly.
I suppose that depends on the quality of the material you're reading. I like the outdoors, but unless I'm somewhere that is both beautiful and novel, a good book makes my synapses buzz a lot more.
