Lying on your right side
Lying on your right side, also known as right lateral decubitus [4], position, can worsen your symptoms of asthma. According to studies, sleeping on your right side can increase vagal tone [5], which will activate the parasympathetic nervous system leading to airway construction. A 1990 study also concluded that sleeping on the right side elevates resistance in the airways of your lungs as you breathe in and out during the night. This effect does not occur in everyone with asthma. So, it is important to try sleeping on your right side to see if it works for you.