Marathon workdays are so common there's even a word for those who put in the longest hours. They're called 'sleep camels' for their practice of catching up on down-time on weekends.

Some of the most "time-starved" people in the country are those who are otherwise doing the best. (Silicon Valley has produced a new species of human beings known as "sleep camels": people who can store up enough sleep at weekends to be able to work flat-out through the week.)

Spotted any Sleep Camels lately in your office? Sleep Camels are ultra-workaholics who go for days without resting, then power-sleep or power-nap for most of the weekend in an attempt to store up energy for the week ahead.