My son will soon be 8. We've noticed in recent weeks that on warm days and after lots of exercise he has smelly armpits. The typical sour adult BO smell. He has been for a run today, done a long bike ride and been on the trampoline lots and needed a shower at bedtime despite being shattered as he was smelly! Is this normal for boys his age? He is very tall for his age. Should I speak to the GP or is this is the normal range? Thanks