Klaus makes some good points. I would add that a big difference is the location. The outdoor setting does not have walls to confine the sounds. The open air setting allows the sounds to escape. The rooms create an echoed sound. This ambient sound can be tough to process. Wearing a set of foam ear plugs will decrease this echo based ambient sound.

For me, the limit would be an hour or so. Three hours is a lots of auditory stimulation.

There is also a difference in visual stimulation. The outdoor location allows much of the visual stimulation behind a person across the table to be at a distance and in less focus. This out of focus stimulation is much easier for the brain to ignore. The wall hangings, etc. in a room puts the background stimulation within a normal focus range requiring the brain to try to process this additional visual stimulation. An example would be how the brain wants to switch from a face to the wall and back continually in the indoor settings.

Add the sound and visual overload and there is a huge difference between the indoor and outdoor settings.

A small addition to the outdoor setting is the fact that the plate before you is a common point of focus where there is no background clutter.

So, the two environments have very different stimulation challenges.

I bet that there were symptoms manifesting in both situations, even though more in the indoor locations, that if understood would be indicators of the brain's struggles and fatigue levels.

My wife can tell by the look in my eyes when I have hit my limit. We were at an event at the governor's mansion for a friend who was crowned State Rodeo Queen. I made frequent us of the outdoor patio area to give my brain a break from all of the stimulation. I did leave in a fatigued state but not as fatigues and overwhelmed as I could have been had I not taken the patio breaks.

Learning to recognize the brain's response to these environments can greatly help one avoid overload.

Hope this helps.

My best to you all.