Variation in the cold shock response (CSR) can be explained by physiological factors, habituation; and possibly "psychological" influences. Acute anxiety on cold-water immersion (CWI) increases the magnitude of the CSR in unhabituated volunteers and eliminates the reduction in the response seen after habituation. Recently it was demonstrated that habituation of the CSR includes a significant perceptual component. When the threat of CWI scenario was reduced, anxiety associated with being immersed was also reduced. In contrast, prolonged anxiety during repeat CWIs may prevent habituation. Therefore, it was hypothesized that prolonged anxiety reduces the extent of CSR habituation.