I recently started exercising and I sweat alot especially on my head. I want to wash my hair but I'm not sure how many times I have to wash as I have been exercising everyday. I have shoulder length hair
If you sweat, you should wash them after your workout (depending on how sweaty they are).
I personally shampoo once a day.
You can use some light shampoo that doesn't damage them. I also use an app to make sure the shampoo I use doesn't damage my hair or scalp. It's called Yuka. I'm not sure if that's available in your country though.