Dehydration synthesis and hydrolysis break down of muscle fibers uses and produces water. We aren’t perfectly efficient and need the extra water. Additionally there quite a bit of waste produced that need water to transport it out. Ions like sodium, calcium, and potassium are also moving quite a bit and can dehydrate if you are pushing yourself.
WeakBet6081 t1_je6x47b wrote
Reply to People who lift weights are told to drink plenty of water, because "muscles need lots of water." But what exactly are the muscles doing with the water? by LongSong333
Dehydration synthesis and hydrolysis break down of muscle fibers uses and produces water. We aren’t perfectly efficient and need the extra water. Additionally there quite a bit of waste produced that need water to transport it out. Ions like sodium, calcium, and potassium are also moving quite a bit and can dehydrate if you are pushing yourself.