Poor posture of the head forward when using the cell phone can result in a decrease in the vital capacity of the lungs by up to 30%.
This lack of air can lead to cardiac or vascular problems.
Flexing the neck and head to see the cell phone requires an isometric contraction of the neck muscles to maintain an imbalanced posture. By raising the cell at eye level relaxes the stress of the neck. It is important to keep the arm relaxed.