^ Morales P, Hurst DP, Reggio PH (2017). Kinghorn AD, Falk H, Gibbons S, Kobayashi J, eds. "Molecular Targets of the Phytocannabinoids: A Complex Picture". Progress in the Chemistry of Organic Natural Products. Progress in the Chemistry of Organic Natural Products. Springer International Publishing. 103: 103–131. doi:10.1007/978-3-319-45541-9_4. ISBN 978-3-319-45539-6. PMC 5345356. PMID 28120232.
Sleep is an essential component to maintaining health. In children, sleep is also vital for growth and development. Ongoing sleep deprivation has been linked to an increased risk for some chronic health problems. In addition, sleep deprivation has been shown to correlate with both increased susceptibility to illness and slower recovery times from illness.[47] In one study, people with chronic insufficient sleep, set as six hours of sleep a night or less, were found to be four times more likely to catch a cold compared to those who reported sleeping for seven hours or more a night.[48] Due to the role of sleep in regulating metabolism, insufficient sleep may also play a role in weight gain or, conversely, in impeding weight loss.[49] Additionally, in 2007, the International Agency for Research on Cancer, which is the cancer research agency for the World Health Organization, declared that "shiftwork that involves circadian disruption is probably carcinogenic to humans," speaking to the dangers of long-term nighttime work due to its intrusion on sleep.[50] In 2015, the National Sleep Foundation released updated recommendations for sleep duration requirements based on age and concluded that "Individuals who habitually sleep outside the normal range may be exhibiting signs or symptoms of serious health problems or, if done volitionally, may be compromising their health and well-being."[51]

In Japan, hemp was historically used as paper and a fiber crop. There is archaeological evidence cannabis was used for clothing and the seeds were eaten in Japan back to the Jōmon period (10,000 to 300 BC). Many Kimono designs portray hemp, or asa (Japanese: 麻), as a beautiful plant. In 1948, marijuana was restricted as a narcotic drug. The ban on marijuana imposed by the United States authorities was alien to Japanese culture, as the drug had never been widely used in Japan before. Though these laws against marijuana are some of the world's strictest, allowing five years imprisonment for possession of the drug, they exempt hemp growers, whose crop is used to make robes for Buddhist monks and loincloths for Sumo wrestlers. Because marijuana use in Japan has doubled in the past decade, these exemptions have recently been called into question.[150]

Health science is the branch of science focused on health. There are two main approaches to health science: the study and research of the body and health-related issues to understand how humans (and animals) function, and the application of that knowledge to improve health and to prevent and cure diseases and other physical and mental impairments. The science builds on many sub-fields, including biology, biochemistry, physics, epidemiology, pharmacology, medical sociology. Applied health sciences endeavor to better understand and improve human health through applications in areas such as health education, biomedical engineering, biotechnology and public health.
Canada is specialized on oilseed production and processing, so that hemp oil and grain are much more suitable than fiber. Because of the extensive development of oilseeds in Canada, there is extensive capacity to produce high-quality cold-pressed hemp oil. Canada in the last 5 years has made great advances in the growing, harvesting, and processing of hempseed, and indeed has moved ahead of the EU in the development of raw materials and products for the natural foods, nutraceuticals, and cosmetics industries. In the EU, a yield of 1 t/ha is considered good. In Canada, extraordinary yields of 1.5 t/ha have been realized, at least locally, although in the initial years of hempseed development in Canada yields were often less than 500 kg/ha. In 1999, the year of largest Canadian hemp acreage, yields averaged 900 kg/ha. (Ideally, hemp seed yield should be based on air dry weight—with about 12% moisture. Hemp yields are sometime uncertain, and could be exaggerated by as much as 50% when moist weights are reported.)

Experimental studies have also been conducted in order to assess the effect of cannabis use on schizophrenia. D’Souza et al. (2004) administered varying levels of the main ingredient in cannabis to healthy individuals with a history of cannabis exposure (but not abuse) and found that the subjects in the study displayed both positive and negative symptoms associated with schizophrenia, although all symptoms disappeared by about 3 h. D’Souza et al. (2005) conducted a follow-up study in which they followed the same protocol, but with clinically stable schizophrenia patients. Again, they found brief increases in positive symptoms, even if the patients were already taking antipsychotics.
In addition to safety risks, many jobs also present risks of disease, illness and other long-term health problems. Among the most common occupational diseases are various forms of pneumoconiosis, including silicosis and coal worker's pneumoconiosis (black lung disease). Asthma is another respiratory illness that many workers are vulnerable to. Workers may also be vulnerable to skin diseases, including eczema, dermatitis, urticaria, sunburn, and skin cancer.[61][62] Other occupational diseases of concern include carpal tunnel syndrome and lead poisoning.