I only skimmed over it briefly but today I was wondering myself what the role of sweat (on the scalp) played in the rate of loss.
For example wearing a baseball cap all day or frequently, especially during summer months in AU, increases scalp sweat and oiliness so to speak. This could not be beneficial to hair especially in those suffering from hair loss.
your hair is dead. why should sweat in your scalp affect your male pattern baldness? however, an oily scalp is sometimes common in balding man, but certainly isn't a cause of it.
id figure the best time would be after a hot shower when all your pores are open adn the skin is soft. it would absorb better. when you sweat you have oily pores and salty wet skin.