Occasional all nighters and transatlantic flights are not so detrimental, but waging a constant war on the natural body clock does more harm than you think. For those who consistently forego the required shut-eye for the sake of startup success, this means you.

Adults between the ages of 18 and 64 require seven to nine hours of sleep nightly, according to recent recommendations from the National Sleep Foundation. And if this goal isn't met, your brain won't be the only tired part of your body.

All internal organs--and even your cells--have specific functions that may be slowed and curtailed, if sleep patterns are constantly cut short. 

What's more, in her article, "Circadian Surprise: How Our Body Clocks Help Shape Our Waistlines," National Public Radio reporter Allison Aubrey finds that besides disrupting our productivity at work and making us lethargic, messing with sleep patterns may have a deleterious affect on health. 

Fred Turek, a circadian scientist at Northwestern University, tells Aubrey that the body reacts to unnatural patterns such as midnight snacks or overnight shifts at a job by altering it's functions. For instance, one's blood pressure, hormones and blood sugar control can go haywire.

"What happens is that you get a total de-synchronization of the clocks within us," Turek says, "which may be underlying the chronic diseases we face in our society today." He cites a correlation between lack of sleep and the increased risk of obesity and metabolical diseases such as Type 2 diabetes. 

The International Journal of Obesity reports that the weight loss therapy "should incorporate not only the caloric intake and micronutrient distribution--as is classically done--but also the timing of food."

This evidence is not limited to weight management. Aubrey writes that "different systems in the body are programmed to do different tasks at different times," and interrupting that flow can cost us our health. 

Come nightfall, the body not only rests the brain, but it signals all other clocks in every organ-- pancreas, stomach, fat cells-- to rest. 

At a time when society is awake twenty-four hours a day, instead of delegating tasks to every minute of a day, we need to let our bodies rejuvenate and recuperate with a good night's sleep.