Cailliet Director of the Department of physical Medicine and Rehabilitation, Univercity of Southern California, concluded that foward head posture can add up to (30) pounuds of abnormal leverage on the spine,reduce lung capicity by much as 30%,which can lead heart and blood vascular disease. He deterined a relationship between forward head posture and the digestive system as well as endorphin production affecting pain and the experience of pain.
In my experience, most people who suffer from a lot of headaches also have a neck problem. I did an analysis of 150 patients who have come to me for treatment for their headaches (70 had migraines, 80 had chronic headaches) and overall 94% of them had a distinct upper neck dysfunction i.e. twists and strains in the upper neck vertebrae and muscles. Most suffered from neck pain or stiffness as well as their headache. I found that the majority of these people got benefit from my osteopathic treatment which in particular is aimed at helping to loosen the tight muscles and joints in the neck. This, in turn, helps to take the pressure off the nerves that go into the head and so lessen the headaches. A lot of headaches are actually referred pain from the neck.