Well, Stella is on the right track.
Although I can run & exercise our Rottie & he gets tired....entering him in a dog show (which requires very little physical effort) really makes him exhausted at the end of a day.
If any of you been to a dog show or seen it on tv...the dog is 'maybe' in the ring no more than 2-6 minutes. Alot depends how large the class is, if they win, & how far they go winning.
After talking to a bunch of people that have been showing for years....they feel there's a direct connection involving showing a dog & shortening it's life span.
I've noticed with our dog, it is very stressful on him. I haven't been able to determine if it's excited behaviour, nervousness, anxiety/stresses, or a combination of the above. The last show I had him in was an outdoor event. Being in So Cal it was a pretty hot morning. Even it being an 8:30 show, by the time he was in the ring at 9:30, the temps were heading in the 90's. He was not happy & was really not wanting to be out there. There's pressure placed on him because for those few minutes. He's really wanting to please & work for me, but also has his own intentions too.
I've decided never to enter him in an outdoor show again unless it's in the Winter. The last thing I want to do is make this a negative experience for him. I personally would forget showing all together but I do enjoy being competitive. I haven't been doing this very long & couldn't tell you if our dog enjoys it or not. He does seem to like mingling with the other dogs & being around dog people (which at a dog show....there's a lot of). I've been fortunate sometimes to handle some other people's dog in the ring & not just my own. I have found that some dogs kind of like strutting their stuff but still get that exhausted nervous emotional feeling afterwords.
I'm not sure if I'm answering the question directly...but yes...I believe dogs get exhausted mentally by even thinking & w/o working on a physical type activity.