Mental, physical and emotional effort can result in us being “ego depleted”, which means we are running low on the resource needed for those kinds of effort. In this state we are less likely to benefit from the relaxation of watching TV.
Watching TV and playing video games may feel like a bit of lazy time-out to us sometimes, but can actually be very useful in aiding recovery from stress according to some studies. On the other hand, some studies show the opposite.
Leonard Reinecke et al looked into why some people benefitted from media usage and some didn’t. They found that people’s own appraisal of their media usage affected whether they benefitted or not. It seems that if someone is ego-depleted they are more likely to feel that watching TV is a waste of time and that they are putting off more important things that they should be doing. This prevented them from relaxing properly and reaping the down-time benefits of watching TV or playing games.
Those who were not ego-depleted were less likely to feel worried about wasting time and were able to gain the full benefits of the relaxation.
This, of course, causes an awkward situation: those who most need the relaxation of watching TV (those who are ego-depleted) are least likely to get it.
I should add that these findings in some ways go against other research into subjects like ego depletion. For example, ego depletion generally makes people less likely to feel guilty, so it is unclear why they felt guilty in this case.
