Comparing Bronchodilation of Symbicort With and Without Valved Holding Chamber (Aerochamber Plus)

This study will compare the amount of bronchial tube relaxation from the Formoterol medicine contained in the Symbicort pressure Metered Dose Inhaler(pMDI)(a combination of Budesonide, a steroid, and Formoterol, a drug which relaxes the bronchial smooth muscle. The comparison will be using the pMDI in the usual fashion to the pMDIs and a spacer which allows more time for breathing in the medication. Breathing tests will be measured over a 12 hour period for the comparison.