If I care about the result I find it too stressful.
I first noticed this phenomenon in my dad. It was the final match of the Welsh grand slam of 2005 (v Ireland) and I think it was the last rugby match he watched. It was certainly the last I watched with him, and we had supported Wales together for something like 40 years. Despite the fact that Wales were out of sight at half time, the further into the second half we went, the more distressed he became. He was 90 at the time, but completely compos mentis, but I really could not understand why he found it such an excruciating experience.
During the past couple of weeks I have discussed this phenomenon with two pals. Mel, a former teaching colleague and Tottenham supporter, and My Mate Terry Who Art In Sibton, lifelong Sunderland supporter and a veteran of the 1973 Cup Final (as a supporter). Neither enjoys watching sport any more, if they are supporting one of the teams. Both are in their 70s.
I had a long natter with Terry about this yesterday evening. He said he prefers watching club rugby to football these days, and likes to watch Newcastle Falcons, but I think that it's not just the stress that Terry, Mel and I dislike. It's also the nonsense (in rugby matches) of flame throwers and gratuitous noise, the tedious cult of celebrity, the massive amounts of money, the "mind games" between the teams in the run up to the matches, and lots of other stuff, but when it came down to it was are all prepared to watch the recordings when we know the result, and of course they still involve the other stuff we find distasteful. Terry is a self-professed couch potato and often has sport on the television even when he's doing something else so that he can look up when the commentator starts to get a bit excited. But mostly he is a neutral so the stress is absent.
Terry and I quite often follow the minute-by-minute text descriptions. That was how I followed the Wales - England match this afternoon. Somehow being told about it by a third party takes the edge off it. It's still pretty stressful though.
I have a theory that the older you are, the less fun an adrenaline rush is. It's a pretty basic function, and in a young caveman it is very likely to lead to a reward of some kind, whether a meal, if your are hunting, or an act of procreation if you are not, so it's quite exciting. But as an older caveman, I reckon that the adrenaline rush is more likely to be a precursor to becoming a meal or the victim of some conflict or other, so the only reward you have to look forward to is a bit more life until the sabre-toothed tiger finally catches up with you.