Social networking can impact health. The less a person moves the more weight that person is likely to gain, and few calories are being burned while sitting in front of a computer. Computer monitors have been proven to cause eye strain, leading to poor eyesight. Little movement has been proven to lead to muscle weakness, less muscle development and, in some cases, bone loss. Back, neck, and joint pain have been associated with too much computer use. Social networkers often spend hours networking, leading to weight and health issues.