I'm not completely sure since I'm not an expert but I have been told for pool swimming that many people slather their hair in oil/conditioner before getting in the water to protect it. I tried the oil one time in the pool and it definitely worked because when I went to wash my hair afterwards, it was soft and didn't feel stripped and rough and generally just gross after chlorine exposure. So I figure if it works for the pool, I guess it'd work for the lake too.