Nocturnal worsening of asthma is common. It is characterized by overnight exacerbation of asthma symptoms such as shortness of breath, chest tightness, coughing, and wheezing, increased need of asthma medications and airway hyperresponsiveness, and decline in lung function (1). Nocturnal asthma has been attributed in part to circadian variations in lung function and airway inflammation. However, other factors including sleep, supine posture and lung volume may also contribute to nocturnal asthma. Current treatments often improve nighttime asthma symptoms. Nevertheless, nocturnal asthma is still common. Up to 2/3rd of asthma patients report nocturnal asthma symptoms, and many asthma related events occur at night, indicating poor asthma control. Results from an ongoing study suggest that in asthma while subjects were supine, fluid shifted out of the legs and accumulated in the thorax (rostral fluid shift) contributing to lower airway narrowing in asthma. A previou study has shown that wearing compression stockings during the day reduces fluid retention in the legs, reduces nocturnal rostral fluid shift out of the legs, and improves sleep apnea (2, 3). The aims of the proposed study is investigate whether off-the-shelf, below the knee compression stockings will attenuate nocturnal fluid shift and lower airway narrowing in asthma.