We've all been told that sleep has benefits, especially in college where sleep becomes more of a luxury than anything else. Sometimes there is just not enough time, but more often than not we are unwilling to give up the things we love just to have two more hours of sleep. But nonetheless I think it's safe to say that we have all experienced benefits from a good nights sleep. We need that extra energy so that the next day can suck it right out again. But why is it that we feel rested after sleeping for a decent amount of time?
Scientists have been trying to answer this question for a long time and from various angles. More recently researchers have suggested that a difference in the brain's ATP level might be linked to this phenomena. It's an interesting thought since ATP is the energy source of the body. But why the brain?
The brain only encompasses about 2% of our entire body mass. However it is one of the prime energy users. The brain utilizes about 20% of glucose and oxygen, both prime energy sources for the body. That means that 1/5 of the energy is being used by an organ that only comprises 2% of the body. So it does make sense to take a closer look at the brain when it comes to ATP levels.
A recent study published in the Journal of Neuroscience has shown that there are indeed differences in ATP levels during not only awake and sleep states but also the different sleep states and different brain areas. The results showed an ATP surge during the sleep state occurring at the onset hours of sleep.
So what does this surge do? Sadly enough it doesn't magically provide extra information for the next days exam, though that would be nice. The surge serves as nourishment to our brain, so that biosynthetic pathways can be restored. So in a way these surges of ATP are little helpers.
While working on this research, the researchers discovered that the ATP surges showed a correlation to the EEG NREM delta activity in spontaneous sleep. EEG NREM delta activity simply means that the waves generated by the NREM sleep period were of size delta and measured by an EEG. In the NREM period the neuronal activity drops and less energy is consumed which is exactly when the surge of ATP would occur.
Now how is this helpful to us other than just having gained some extra knowledge? The research shows the importance of sleep to our bodies' homeostasis. During the day we (hopefully) have high neural activity thus we are using up a lot of energy/ATP, but during the night we have low neural activity and thus use up less energy. So we get an energy surge at the onset of our sleep to take care of the restoration of biosynthetic pathways; at this point it is important that we are not using that energy surge for other purposes (like neural activity). So if we wake up to early because class might just be about to start, we have not been able to fully restore the biosynthetical pathways before our neural activity sets in again.
So you might argue that sleep is an important factor in test preparation as well. You might have studied as well as possible but if you did not let your body do its work over night, your biosynthetical pathways are not up to date.
So be kind and give your body a decent amount of sleep, that way you only have to worry about the actual studying.
Full article: http://www.jneurosci.org/content/30/26/9007.full