M.C. Borges, E. Ferraz, J. Terra-Filho and E.O. Vianna. Protective effect of bronchial challenge with hypertonic saline on nocturnal asthma. Braz J Med Biol Res, March 2008; Volume 41: 209-214.

Figure 1. Overnight forced expiratory volume in 1 s (FEV1) variation on the control and study days. FEV1 nocturnal variation (reported as percent of basal value) of 12 asthmatic subjects on the control day (basal FEV1 overnight reduction) and study day (following challenges). On the study day, subjects underwent hypertonic saline challenges at 16:00 and 18:00 h. The horizontal lines indicate the means.