Jet Leg is inevitable when you are covering long distances across the globe but and it can often effect you for days. This can slow down or alter your first couple of days in a new city and keep you from enjoying the best of what that city has to offer.
I usually am not affected by a 6-7 hour time change that much. Simple things like naps or getting some extra sleep on the plane usually does the trick for me. However, last time I flew to SE Asia I really felt it and I felt like a zombie around 9pm the first night even after getting plenty of sleep on the flight. My sleep schedule was off for what seemed like 4 days and that was the most I had ever been effected by a time change.
Luckily, Yumi Sakugawa has some tips for us and you never know they might just help you next time you make a big jump in time zones.