3 year old always smells like sweaty BO..

So my 3 year old gets bathed every night sometimes every other night but no matter how often he is bathed this child still has this lingering body odor that smells like he's been running around sweating all day even right after a bath, it's gotten worse over time to the point I can not get the smell of sweat out of his room even after washing everything that can possible be washed. Do I need to be concerned with this? Should I bring it up to his ped? He's my 1st child his little brother is only 5 weeks so I've never encountered this problem before. Any advice?