http://travel.nytimes.com/2012/08/19/travel/a-battle-plan-for-jet-lag.html?pagewanted=1

"Major League Baseball teams using season records from 1991 to 1993 showed that the team that had just completed eastward travel would give up more than one run than usual in every game"

On a related note, if you need cash money in Europe, your best exchange rate will come from an ATM (just withdraw all at once to cut down on fees). Credit cards are good too.