Don't lean in -- kick back! (MoneyWatch) Americans are famous for working longer days, weeks and years than people in most other nations. Already given less vacation, we don't even use it all, and then we stay connected to work during the time off we do take. We celebrate overwork, all-nighters and heroic globetrotters, the corporate soldiers who lean in and man up. But should we? If you're just back from vacation, you may be feeling overwhelmed, determined to stay late and clear the backlog. Don't do it: Don't waste whatever small amount of a break you've just had. At Harvard, Teresa Amabile has studied creativity for years. One research study followed 12,000 executives as they kept diaries about their working lives. What she found was that people are typically more creative when under less pressure. We already know that stress reduces people's capacity to think, that fatigue leads to tunnel vision and that multi-tasking is exhausting and inefficient. What this all adds up to is that clocking up the hours may look heroic but in fact it's just ineffective. And not much fun. So if you're in a job where you're expected to have ideas, display initiative and solve problems, what should you be doing? Schedule thinking time. I had a regular calendar appointment -- Thursdays at 11 - when I took a walk or a drive just to think about my work. I let my mind wander, had ideas, solved problems and remembered important things I needed to do. That one hour was one of the most productive moments in the week. Get a good night's sleep. Missing one night incurs the same cognitive cost as being over the alcohol limit -- without the fun. So instead of sitting up bleary-eyed doing email until midnight, quit at 10 and get a decent night's sleep. Take vacation. Real vacation. Get other people to take your calls and handle your emails and return the favor when you get back. I've just had 5 whole days off, studying Palladian architecture in Italy and I feel like I was away for a month. My first real break for two years, it was great. I should -- and shall -- do it again soon. Say 'No' more often. All the networking events, conferences and meetings: Ask yourself if they will all fail in your absence. If they won't, then stay put and do real work. Adopt the mantra of Ove Arup, founder of one of the world's biggest and most innovative structural engineering firms. "Take it easy" was his motto. Because he believed that work was something to be enjoyed -- and that when you enjoyed it, you did it better. It surely hasn't hurt his firm, which has not had a year without growth.