An active breathing system is for an aseptic overalls arranged to be worn by a user. The system includes an aeration device and a surrounding air inlet, and aseptic overalls for a cleanroom. The aeration device includes a first longitudinal hollow body arranged to receive a ventilator connected to an energy source, an air suctioning tube in fluidic communication with the longitudinal hollow body, and the surrounding air outlet in fluidic communication with the longitudinal hollow body, and arranged to direct surrounding air upwards. The aeration device has an air inlet on the aseptic overalls and arranged to enable passage of the surrounding air on the outside of the aseptic overalls in an inner portion of the aseptic overalls.