Any process that results in a change in state or activity of a cell or an organism (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of a low fluence red light stimulus. Red light is electromagnetic radiation of wavelength of 580-700nm. Low fluence red light is defined in this case as short pulses of red light followed by darkness, providing a light level of 0.001-0.1 mmol/m2/sec.