Why even dive-pros should beware of CESAsNew research into the physiological impact on scuba divers of carrying out CESAs (Controlled Emergency Swimming Ascents) in training situations has revealed that these exercises can cause lung stress even though there might be no outward signs of it. CESAs are a standard dive-safety procedure for preventing lung over-expansion injuries during an out-of-gas situation. However, pulmonary risks associated with the exercise have been poorly documented in the past, according to the France-based research team. Stress on the lungsAlthough none of the divers displayed any symptoms, their ULCs increased significantly after CESA dives – though not after the control dives. This suggested that the CESAs were causing subclinical pulmonary stress, with analysis revealing marked variability between individual divers.