have done really well with ds age 9 for about two years. He takes one montelukast and two puffs if brown morning and night. This has been brilliant and he rarely needs his blue at all. But he is playing more sport now, athletics and running, and struggling with a tight chest and breathing when finished running. Not a wheeze just tight and tired. I just wondered if his meds need a tweak? The montelukast has transformed him, so I wonder if his brown preventor is not working for him so well. Any suggestions? Thank you...