Neck Pain Affects Breathing.
Researchers at the Technological Educational Institute of Lamia in Greece examined a group of chronic neck pain patients and a group of individuals with no previous incidence of neck pain to see if a correlation exists between neck pain and respiratory dysfunction. They found that neck pain sufferers have significantly reduced breathing capacity and lower respiratory muscle strength. They also noted a strong association between increased forward head posture and decreased respiratory muscle strength.
Cephalalgia, July 2009