An article published in the medical hypotheses offered the following explanation for sleep: The vegetative state is primary and the waking state is a periodic departure superimposed upon the vegetative life.  The profound restorative role of sleep has long been appreciated on a general level, but the physiological events that occurred during sleep and their specific functions remain elusive.
Until we fully understand what goes on inside our body and brain during sleep, we will not be able to answer the question of why 30% of our existence is spent in a state of suspended animation. One fact is clear, however, sleep is much more than idle.
Sleep Is A Much More Active State Than Was Thought
Contrary to the popular conception of sleep as an idle and inert state, it is, in fact, an active physiological event. Within the outward motionless body, electro-neurological oscillations  and cascading hormones define the biologic turbulence of sleep. Furthermore the complex hormonal and brainwave activities that occur during sleep are crucial to a smooth immune system operation, cognitive function, emotional well-being, and physical development.
The importance of nighttime sleep stems from the fact that circadian rhythms which orchestrate all biological processes, are dependent upon the sleep-wake cycle. Thus, it is not surprising that the experimental animals deprived of sleep for extended periods exhibit severe metabolic and neuroendocrine abnormalities, leading to degeneration and ultimately death. In humans sleep deprivation also causes problems. Sleep is particularly important for athletes and others engaged in physical training because it helps stave off over-training syndrome, marked by elevated cortisol levels.
Whether you are an athlete or not, adequate nighttime sleep  is vital to optimizing hormone levels.
The emphasis on nighttime sleep bears elaboration. Studies of night shift workers  showing persistently distorted hormonal rhythms and greater incidents of health problems. These findings have prompted research into endocrine phase shifting techniques.
Light exposure and administration of melatonin were designed to help the woes of night shift workers. The bottom line is while daytime naps can be beneficial on an adjunct basis no amount of daytime sleet and substitute for a good nights sleep.
Daily life imposes a sordid physical, mental, and emotional stressors that conspire to disrupt the biological homeostasis of the body. Nighttime sleep is a time of rest rated reorganization, which the chaotic influence of stress is turned back. Hence, sleep is a bulwark against stress and cortisol increases. Conversely, sleep deprivation amplifies the impact of stress and is capable of raising cortisol levels.
Other hormonal effects of sleep deprivation include: impaired insulin function, alterations in thyroid hormones, decreased growth hormone output, and in men, decreased testosterone levels.  The hormonal effects of sleep deficiency are remarkably similar to the hormonal changes associated with aging. In these two conditions are mutually reinforcing insofar as reduced sleep quality and older individuals is both a case and result of hormonal decline.
Disturbed or interrupted sleep can cause growth hormone output to be reduced or aborted. Therefore, not merely sleep but sound sleep, it’s essential to maximizing growth hormone release.
Phases of Sleep
The major episodes of slow wave sleep  occurred during the first half of the night at which time surging growth hormone: sides with the lowest cortisol levels of the day. Conversely, the second half the night is marked by diminished growth hormone output, and cortisol levels rising toward a morning peak.
Sleep researchers postulate that the early period, during which growth hormone levels and cortisol levels are maximally disassociated in favor of growth hormone, it is a time of uniquely significant anabolic activity.
With advancing age, the nighttime sleep induced growth hormone pitfalls in the cortisol levels rise, consonant with the general age related reduction in the anabolic/catabolic ratio. The hormonal shift towards catabolism is largely responsible for the physical deterioration of aging and the closing of the nocturnal anabolic window may play a central role in this connection.
Growth hormone release is influenced not only by aging, but also buy diet.  Insulin is antagonistic to growth hormone. For precisely, the cost of growth hormone inhibition is not high insulin but rather high blood sugar which because insulin is secreted to bring down the blood sugar level, overlap some time with the high insulin levels. The issue here is whether consuming carbohydrate before bed, by causing a rising blood sugar, will blunt the nocturnal growth hormone search.
Interestingly, there is some evidence indicating that sleep related growth hormone spurt is not suppressed by hyperglycemia. This suggested that repeated observations of the suppressive effect of high blood sugar levels on growth hormone release in the waking state may not apply equally to the sleeping state-but more studies are needed to clarify this. In any event, other studies show that fasting prior to sleep can heighten sleep sleep related growth hormone output.
Therefore, based on the evidence in both the sleeping and waking period, going to bed with a belly full of carbs is hormonally not wise and may drop,  if not nullify, night time growth hormone release. Conversely, allowing an appropriate amount of time after eating carbohydrate before going to bed will help maximize nighttime growth hormone release. Therefore, to enhance growth hormone output, don’t eat carbs within ninety minutes of going to bed.
Hours of sleep that begin earlier and end earlier or more in harmony with hormonal rhythms and are more valuable than an equivalent amount of sleep that begins later an insulator. This is one of the many instances in which scientific research validates ancient wisdom: the proverb one hours sleep before midnight is worth two after is correct in essence. Accordingly, to optimize hormonal status and maximize the darkness hours spent sleeping and maximize daylight hours spent awake.
This is another way of expressing the early to bed early to rise adage if you balk at this recommendation because you consider yourself a night person you will probably find that once you change your sleeping pattern you become a morning person.
 Patient. Vegetative States Available from: http://patient.info/doctor/vegetative-states
 U.S. National Library of Medicine. Resting-State Oscillatory Activity Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3638261/
 Rutgers. Why is Sleep So Important to Health? Available from: https://njaes.rutgers.edu/sshw/message/message.asp?p=Health&m=74
BBC. Are night shifts killing me? Available from: http://www.bbc.com/news/magazine-33638905
 WebMD. 10 Things to Hate About Sleep Loss. Available from: http://www.webmd.com/sleep-disorders/features/10-results-sleep-loss#1
 Sleep Medicine at Harvard Medical School. Why Sleep Matters. Available from: http://healthysleep.med.harvard.edu/healthy/glossary/n-p
 U.S. National Library of Medicine. Effects of dietary protein and growth hormone-releasing peptide (GHRP-2) on plasma IGF-1 and IGFBPs. Available from: https://www.ncbi.nlm.nih.gov/pubmed/15713362
 U.S. National Library of Medicine. Biological Effects of Growth Hormone on Carbohydrate and Lipid Metabolism. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2815161/