My 12 year old son has exercise induced asthma. He just finished cross country running season and would take one puff of an inhaler before running a 2 mile race (about a 6 minute mile +/-). It worked wonders. Now he is starting basketball tryouts and the practices are 2 hours long (for tryouts) with a ton of sprinting. Is it safe for him to use the inhaler once before practice and once half way through?