Sleep is one of the most important activities that we, humans, take part in every day. According to National Heart, Lung, and Blood Institute, "good night's sleep improves learning" and plays a role "in healing and repair of your heart and blood vessels." In addition, sleep deficiency may lead to "trouble making decisions, solving problems, controlling your emotions and behavior, and coping with change," and "sleep deficiency also has been linked to depression, suicide, and risk-taking behavior." Yet, middle school and high school hours almost promote sleep deficiency by demanding students to complete numerous homework assignments. Many of us in college risk sleep deficiency over academic performance and career-oriented extracurriculars.
Interestingly, a study in 2016 revealed that "short sleep duration, poor sleep quality, and late bedtimes are all associated with excess food intake, poor diet quality, and obesity in adolescence." Although it may seem like then that obesity is not necessarily a biochemical pathway and rather the behavior of individuals during the time that they are awake, research has shown otherwise. In a 2004 study, a clinical study measured "plasma leptin and ghrelin levels and subjective ratings of hunger and appetite" in 12 healthy men around 22 years old. Leptin is a molecule produced by the fat cells of the body, signaling satiety. In other words, leptin is primarily responsible for suppressing hunger. Ghrelin, on the other hand, is produced mainly by the stomach and small intestines which signals hunger. The results of the experiment revealed that deprivation of sleep was associated with "decreased leptin levels, increased ghrelin levels, and increased hunger and appetite." Perhaps there are molecular mechanisms beyond our conscious control that induce hunger with less sleep.
Other experimental evidence confirms this idea. In a controlled experiment in 2013 with 225 healthy adults ranging from 22 to 50 years old, "sleep-restricted subjects gained more weight than control subjects." After five consecutive nights with 4 hours of sleep per night, the participants in the sleep restriction group gained 1 kg (2.2 pounds) more. In a different 2013 study, 37 children between the age of 8 to 11 years underwent a 3-weeks of assigned sleep such that in the first week, all children slept for their typical sleep duration. For the second week, the children were randomized into a decreased sleep group (sleep duration shortened by 1.5 hr) or increased sleep group (sleep duration increased by 1.5 hr). During the third week, the children were subjected to whichever group they were not during the second week. The authors showed that "compared with decreased sleep condition, during the increase condition, children reported consuming an average of 134 kcal/day less."
These studies on sleep go to show how sleep is important not only for cognition but also our physiological states. When given the choice, prioritizing other activities oversleep may not be so beneficial to our health. It also may be worthwhile to advocate for shorter school hours for children, given these data.
