Singing is the act of producing musical sounds with the voice and augments regular speech by the use of sustained tonality, rhythm, and a variety of vocal techniques. A person who sings is called a singer or vocalist. Singers perform music (arias, recitatives, songs, etc.) that can be sung with or without accompaniment by musical instruments. Singing is often done in an ensemble of musicians, such as a choir of singers or a band of instrumentalists. Singers may perform as soloists or accompanied by anything from a single instrument (as in art song or some jazz styles) up to a symphony orchestra or big band. Different singing styles include art music such as opera and Chinese opera, Indian music, and religious music styles such as gospel, traditional music styles, world music, jazz, blues, gazal and popular music styles such as pop, rock, electronic dance music and filmi (film songs).

Singing can be formal or informal, arranged or improvised. It may be done as a form of religious devotion, as a hobby, as a source of pleasure, comfort or ritual, as part of music education or as a profession. Excellence in singing requires time, dedication, instruction and regular practice. If practice is done on a regular basis then the sounds can become more clear and strong. Professional singers usually build their careers around one specific musical genre, such as classical or rock, although there are singers with crossover success (singing in more than one genre). They typically take voice training provided by voice teachers or vocal coaches throughout their careers.

Scientific studies suggest that singing can have positive effects on people's health. A preliminary study based on self-reported data from a survey of students participating in choral singing found perceived benefits including increased lung capacity, improved mood, stress reduction, as well as perceived social and spiritual benefits. However, one much older study of lung capacity compared those with professional vocal training to those without, and failed to back up the claims of increased lung capacity. Singing may positively influence the immune system through the reduction of stress. One study found that both singing and listening to choral music reduces the level of stress hormones and increases immune function.

A multinational collaboration to study the connection between singing and health was established in 2009, called Advancing Interdisciplinary Research in Singing (AIRS). Singing provides physical, cognitive, and emotional benefits to participants. When they step on stage, many singers forget their worries and focus solely on the song. Singing is becoming a more widely known method of increasing an individual's overall health and wellness, in turn helping them to battle diseases such as cancer more effectively due to decreased stress, releasing of endorphin's, and increased lung capacity.

Effect on the brain

John Daniel Scott, among others, have cited that "people who sing are more likely to be happy." This is because "singing elevates the levels of neurotransmitters which are associated with pleasure and well being." Humans have a long prehistory of music, especially singing; before written language, stories were passed down through song, because song is often more memorable. There is also evidence that music or singing may have evolved in humans before language. Levitin, in his This is Your Brain on Music, argues that "music may be the activity that prepared our pre-human ancestors for speech communication" and that "singing. . . might have helped our species to refine motor skills, paving the way for the development of the exquisitely fine muscle control required for vocal . . . speech" (260). On the other hand, he cites Pinker, who "argued that language is an adaptation and music is its Spandrel . . . an evolutionary accident piggybacking on language" (248).

Studies have found evidence suggesting the mental, as well as physical, benefits of singing. When conducting a study with 21 members of a choir at three different points over one year, three themes suggested three areas of benefits; the social impact (connectedness with others), personal impact (positive emotions, self-perception, etc.), and functional outcomes (health benefits of being in the choir). Findings showed that a sense of wellbeing is associated with singing, by uplifting the mood of the participants and releasing endorphins in the brain. Many singers also reported that the singing helped then regulate stress and relax, allowing them to deal better with their daily lives. From a social perspective, approval from the audience, and interaction with other choir members in a positive manner is also beneficial.

Singing is beneficial for pregnant mothers. By giving them another medium of communication with their newborns, mothers in one study reported feelings of love and affection when singing to their unborn children. They also reported feeling more relaxed than ever before during their stressful pregnancy. A song can have nostalgic significance by reminding a singer of the past, and momentarily transport them, allowing them to focus on singing and embrace the activity as an escape from their daily lives and problems.

Effect on body

A recent study by Tenovus Cancer Care found that singing in a choir for just one hour boosts levels of immune proteins in cancer patients and has a positive overall effect on the health of patients. The study explores the possibility that singing could help put patients in the best mental and physical shape to receive the treatment they need, by reducing stress hormones, and increasing quantities of cytokines- proteins of the immune system that can increase the body's ability to fight disease. "Singing gives you physical benefits like breath control and muscle movement and enunciation, as well as the learning benefits of processing information" says a musical director and accompanist in the study. The enunciation and speech benefits tie into the language benefits detailed below.

A recent newspaper article by the Toronto Star states that everyone to sing, even if they are not musically talented, because of the benefits it has for the health of the individual. Singing lowers blood pressure by releasing pent up emotions, boosting relaxation and reminding them of happy times. It also allows singers to breathe more easily. Patients with lung disease and chronic pulmonary disease experience relief from their symptoms from singing just two times a week. In addition to breathing related illness, singing also has numerous benefits for stroke victims when it comes to relearning the ability to speak and communicate by singing their thoughts. Singing activates the right side of the brain when the left side cannot function (the left side is the area of the brain responsible for speech), so it is easy to see how singing can be an excellent alternative to speech while the victim heals.