Swimming OR trampolining are both incredibly intense/draining, so I would only do one of those in a day. They tend to be vv good for wearing them out, but you can end up with too much of a good thing! You don't want them to be worn out by lunchtime 
Essentially the idea of wearing them out is kind of like walking a dog, you'd take them for walks 1-2 times a day, and if you have a high energy dog you might add a third session of brain games at home or a third, gentler walk. You would not spend literally all day in high intensity activity with them because everyone would be exhausted.
I think "exciting" is slightly the wrong word - the way I'd think about this is that it's sort of about energy level of the activity - have you heard of Zones of Regulation at all? They use 4 different colours to describe different "zones" of where our energy level/activity level is. So blue is sleepy/relaxed, green is a sort of calm, concentrated type level which might not have much physical activity but could have more cognitive/brain type activity, red is very intense/high energy such as competitive sports or intense activity like swimming lessons, trampolining, dancing (but could also stand for very strong emotions such as anger, frustration, fear) and yellow is sort of somewhere in between red and green - so perhaps some especially taxing mental stimulation/learning, or a lighter form of exercise like splashing in a pool for fun, running/walking/playing/other kinds of physical activity which aren't AS intense as the red ones.
Then it's about having a balance of that in your day - so toddlers do spend more time in the red/yellow zones compared with older children and adults. People of any age can't spend a long time in the red zone because it's very energy-intensive and tends to drain us, but short bursts of this are OK (in terms of strong emotions or intensive exercise) and can be positive (sometimes we need to push through difficult feelings or tasks in order to grow). Toddlers probably need more yellow in terms of physical activity than green. But aiming for a balance of blue (chilling) and green (quiet concentration/brain exercise) and yellow (stretch/physical movement) and short bursts of red, not directly running on from one another if possible, but separating them out if there will be more than one in a day.
Does he go to nursery?