Stress is defined by Selye as a situation of arousal for an organism. Fight or flight response. Stages are alarm, resistance, exhaustion, death. Optimal level of stress. Turtles, racehorse, average.
Turtles use external strategies primarily in low stress situations.
Otherwise tend to use denail, resignation, rumination. Racehorses use external strategies primarily in moderate or high stress situations. Otherwise tend to use emotions. As health status deteriorates, or if social support is too little or too much, internal coping strategies become common. Effective coping can be external or internal, but has to be appropriate to the situation.