For the first time in many years, I didn't take a vacation during the winter. It was a costly mistake. By the time I left for vacation three weeks ago, I was feeling spent. That's not a complaint. One reason for my fatigue is that The Energy Project has grown so rapidly during the past year. Managing our growth has prompted a whole new set of challenges.

For the first two weeks of my summer vacation, I let work go almost completely, in part because I had nothing left to give and in part because I knew how valuable it would be to chill out. I played tennis and worked out. I spent time walking on the beach with my wife. Family members came for visits, and we spent a lot of time just talking on the porch. I also read a lot of books — mostly fiction, which I rarely do when I'm working.

I did check my email occasionally, but I rarely responded. Each day, I felt a little more rejuvenated, much the way you sense your strength returning after an illness. In truth, I was hoping time away from the office might prompt some creative thoughts about our business, but for two weeks not a single interesting idea entered my mind.

In the third and final vacation week, something changed. I felt drawn back to reading non-fiction, specifically to books related to my work. I reread Tribal Leadership, which makes a compelling case that the vast majority of leaders operate at sub-optimal levels of personal development, and that the higher the level they reach, the more successful their organizations become. I also read The Fear of Insignificance, an extraordinary book by the Israeli psychiatrist Carlo Strenger about how our behaviors are powerfully, unconsciously and often pathologically influenced by our deep need to feel we matter.

These books, along with a couple of others, shifted my mind into high gear at a time when I was unburdened and undistracted by the preoccupations of everyday work. In short, I had time to truly reflect and think strategically rather than tactically.

I also learned about the importance of vacations from observing others on our team. The intensity of demand had begun to wear them down, too, and it showed up in a collective tendency to be more emotionally reactive — shorter and sharper — and more willing to settle for an easy solution rather than do the hard work necessary to get the best result.

I encouraged people to take longer vacations — we give four weeks beginning the second year of employment — and most did. Two of our employees (who happen to be married) went to Amsterdam for two weeks, fell in love with it and asked if they could work from there for a third week. They worked U.S. hours, set up their phones so clients could reach them dialing their regular office numbers, and it came off seamlessly.

The result is we're headed into the fall with an office of people recharged and eager to face a busy season. The one employee who didn't get away, in part because she was overseeing our move to new offices, grew more and more exhausted until I finally told her she had to take time off. Literally the next morning she ended up in the hospital with an infection. The cause wasn't exhaustion, but I can't help believing it must have made her more vulnerable to illness.

At a broader level, the famed Framingham Heart Study followed 750 women with no previous heart disease over 20 years. Those who took the fewest vacations proved to be twice as likely to get a heart attack as those who took the most. A 2005 study of 15,000 women found that the risk of depression diminished dramatically as they took more vacation. A 2006 Ernst & Young study found that for each additional ten hours of vacation employees took, their performance reviews were 8 percent higher the following year.

The problem is that in the face of relentlessly increasing demand, we're collectively vacationing less and for shorter periods of time. What's the solution?

• Take every day of vacation you're given. Don't hold it over and don't tell yourself the story that you don't have the time to spare. You'll get more overall work done at a higher level of quality if you take your vacations.
• Take some sort of vacation (even if you stay at home) at least every three months.
• Truly disengage when you go on vacation. If you don't, you'll be trading away the value of taking one. If you feel you have to answer email, set aside one short period to do so, and then disconnect the rest of the time.
• Don't settle for three or four days off. Short periods are fine, but they're not sufficient. If you have an intense job, my experience is that it takes at least two consecutive weeks away from work to fully restore yourself.

Reprinted from HBR.org.