How Sleep Affects Your Body, Mind, and Emotions

Sleep has been called the human body’s hidden time: a restorative state that affects everything from your heart and lungs to metabolism, immune function, mood, and even how quickly you recover from injury. Scientists are only beginning to uncover the mysteries of this essential activity that affects every cell and system in your body. But what they do know is that sleeping more or less than your recommended amount can have serious consequences on your mental and physical health.

Until recently, most people considered sleep to be a passive state in which the brain and body shut down and took a break. Research has since reshaped that view, and sleep is now known to play a vital role in keeping us healthy and functioning well. Getting enough quality sleep is important for our brain and body to stay in good shape, but it also helps our memory, emotions, and decision-making.

For millions of years, humans and most other species on the planet have evolved to live according to a 24-hour day-night cycle. During this time, biological patterns like circadian rhythms work alongside the “sleep drive,” a natural desire to sleep that grows in intensity as you spend more time awake. This ensures that you will have enough energy to survive and thrive, and that you will get the rest your body needs.

But while the sleep drive and other parts of your body are at rest, the brain is surprisingly active. The brain has numerous roles, including regulating your body’s internal clock (the circadian rhythm), forming memories, and controlling emotions and coping with stress.

The key part of the brain that’s active during sleep is the thalamus, which sends and receives information from your senses to the cerebral cortex, where it’s processed. During most of the sleep cycle, the thalamus is quiet; however, during REM (rapid eye movement) sleep, it becomes active again, sending and receiving the images, sounds, and sensations that make up your dreams.

Getting adequate amounts of high-quality sleep is critical to your overall health and wellbeing, particularly for children and adolescents. Studies show that lack of sleep can lead to learning and behavioral problems, lowered immunity, obesity, and depression. It can also increase the risk of chronic (long-term) health problems such as high blood pressure, diabetes, cardiovascular disease, and stroke. In addition, getting too little sleep can make it hard to concentrate and be productive. The Centers for Disease Control and Prevention recommends that adults get 7 to 9 hours of sleep per night. But for many people, especially those living with mental and physical health conditions, this can be a challenge. This article explains why that is, what’s happening in your body when you don’t get enough sleep, and what you can do to improve your sleep.