Poor sleep is strongly linked to weight gain, restlessness and lower focus during the day. If you sleep less than the required duration, you’ll probably skip exercising and eating healthy as your focus will be shaky. In an extensive review study, children and adults with short sleep duration were 89% and 55% more likely to develop obesity.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2398753/ The effect of sleep on weight gain is believed to be caused by numerous factors, most commonly hormones and motivation to exercise. Good amount of sleep helps with recovery of muscle as well which helps to exercise at the same level the next day. Studies show that sleep-deprived people tend to have bigger appetite and tend to eat more calories. Sleep deprivation disrupts the daily fluctuations in appetite hormones and is believed to cause poor appetite regulation. This includes higher levels of ghrelin, the hormone that stipulates appetite, and reduced level of leptin, the hormone that suppresses appetite.https://pubmed.ncbi.nlm.nih.gov/15602591/ Sleep is also very important for various aspects of brain function like cognition, concentration, productivity and performance. A study about sleep deprivation has found that sleep deprivation can have similar effects on our brain function as alcohol intoxication.https://pubmed.ncbi.nlm.nih.gov/10984335/ On the other hand, good amount of sleep has shown to improve problem-solving skills and enhance memory performance for both children and adults. In a study on Basketball players, longer sleep has shown to significantly improve speed, accuracy, reflex actions and mental wellbeing. On the other hand, A study on over 2,800 women found that poor sleep was linked to slower walking, lower grip strength, and greater difficulty performing independent activities.https://pubmed.ncbi.nlm.nih.gov/17969465/ People who get less quality and duration than required sleep are at far greater risk of heart disease and stroke. Sleep deprivation can cause prediabetes in healthy adults in as less as 6 days. Many studies show a strong link between short sleep duration and type 2 diabetes.https://pubmed.ncbi.nlm.nih.gov/19910503/ Mental health issues, such as depression, are strongly linked to poor sleep quality and sleeping disorders. It’s been estimated that 90% of people with depression complain about sleep quality.https://pubmed.ncbi.nlm.nih.gov/16259539/ Poor sleep has also been strongly linked with long-term inflammation of the digestive tract, known as inflammatory bowel disease. Researchers are even recommending sleep evaluation to help predict outcomes in individuals with long term inflammatory issues.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3995194/ Sleep loss reduces your ability to interact socially. Researchers believe that poor sleep affects your ability to recognize important social cues and process emotional information. https://pubmed.ncbi.nlm.nih.gov/20337191/