When I wrote a post earlier this year pointing to this classic tweet by Randi Zuckerberg laying out 'the entrepreneur's dilemma', it was clear from readers' responses that it struck a nerve. Based on how many people clicked and commented, it seems that many of Zuckerberg's fellow entrepreneurs are feeling her pain:

But according to time use expert and author Laura Vanderkam, there's no need to be so time crunched. She insists that it's totally possible to have all five -- family, friends, work, fitness, and even sleep. It's an assertion based on her own work examining real-life time diaries and a little simple math.

What are you doing with those spare 52 hours?

The "problem with the Entrepreneur's Dilemma... is that all these areas of life do not take equal time," she argues in a recent Fast Company column. "There are 168 hours in a week. If you spent 60 working--more than the vast majority of people--and slept 8 hours per night (56 per week) that would leave 52 hours for other things. In 52 hours it seems quite possible to exercise for 4 hours, and mindfully see friends for 3 hours, while still having time for family meals or reading bedtime stories."

Of course, she acknowledges, actually squeezing everything in is easier said than done. What looks simple when laid out mathematically, demands some serious time management skills in real life. But Vanderkam asserts anyone can get a handle on their time with just a little mindfulness (she's a big proponent of time tracking).

Using real-life anecdotes from busy professionals (check out the complete post for lots of interesting personal stories) who claim to "have it all," Vanderkam asserts that with thoughtful use of checklists or intensive scheduling (one interviewee dutifully adds sleep and 'unexpected pursuits' to his calendar), you really can shoehorn all your priorities into your allotted hours.

"168 hours is vast, and with a little mindfulness, it all fits," she concludes.

In your opinion, is her message overly optimistic or a healthy reminder of time management reality?