Sleep is vital to how we function. Poor sleep has been linked to a higher risk of cardiovascular disease, diabetes, obesity, and dementia. Sleep deprivation affects your mood, makes you less likely to remember things, and makes your immune system less capable of fighting infections. It also affects performance. You are far more accident-prone and have far poorer judgment when you’re sleepy. As the National Institutes for Health observes, “Sleep deficiency has also played a role in human mistakes linked to tragic accidents, such as nuclear reactor meltdowns, grounding of large ships, and plane crashes.”For people in the military, getting good sleep can be a matter of life and death. This is why the U.S. Army practices the “military method” of sleep. Here, we look at what that means, and how we all can learn from it to get a better night’s rest.