I did 10 hours on foot in the NYPD...outdoors the whole time. You get one lunch break. The rest in on you to do your job. You are getting paid to be visible and answer calls, not take breaks. We walked from the station to our posts or sometimes took a bus....and walked/stood all shift. Can you stop in air conditioned stores and buildings and do a walk/talk to learn your beat...YES! Can you sit in a restaurant to eat your meal.....yes. Can you stand in the shaed..yes.
But if you asthma so bad you can't breather, you have a medical issue that may DQ you. Lose some weight and see a doctor for some long term meds that control such.
-In God we trust. All others, put your hands on the car and don't move.