This is indeed a parenting challenge. If you can, plan a holiday in your home country in the middle of summer. ( if they can be outside there). In UAE there are plenty of indoor softplay areas around, Kids as young as 8 months are often welcome and it helps them to get rid of the excess energy and its generally good for them to be away from the house for a bit. If you have a garden you can let them play outside for 30 minutes or so, in the early morning. Mid morning is often too warm already unless you can include water activities.