Sweaty Jack - Why?

[CureFan]

Something that is bugging me . . . . When Jack is talking to Ben about leaving the island and he asks Ben to let Kate go Jack appears "normal" . . however in the next scene Jack is walking down to the dock to leave and there he sees Locke . .but in this scene Jack is all sweaty and has the big sweat ring around the neck of his shirt.  So . .what happened in between the scenes to cause Jack to get all sweaty?

[Ladybug]

Something that is bugging me . . . . When Jack is talking to Ben about leaving the island and he asks Ben to let Kate go Jack appears "normal" . . however in the next scene Jack is walking down to the dock to leave and there he sees Locke . .but in this scene Jack is all sweaty and has the big sweat ring around the neck of his shirt.  So . .what happened in between the scenes to cause Jack to get all sweaty?

maybe it's hot outside?  or he had to run to get to the dock?  or walk really fast? 

i think it's just assumed that he had to exert himself to get to the dock.  the barracks and the dock aren't exactly next door to each other.

[Jugdish]

They are walking in the jungle. It makes you sweaty