Complex sentence: Traveling east causes more problems than traveling west, because the body clock has to be advanced, which is harder than delaying it, and the necessary exposure to light to realign the body clock does not tie in with the day/night cycle at the destination.
Split into simpler sentences: Traveling east causes more problems than traveling west because the body clock has to be advanced, which is harder than delaying it. Equally important, the necessary exposure to light to realign the body clock does not tie in with the day/night cycle at the destination.