In this regard, general adaptation syndrome was derived at after the three adaptive phases were brought together; alarm reaction, resistance stage as well as exhaustion stage. The process of adaptation was labeled general since it is argued to be produced by agents with general effect. Adaptive involves stimulation that helps in the maintenance of state of inurement. At alarm stage, generalized stimulation of the nervous system is believed to be automatic stimulation in the initial stages of the alarm reaction. An occurrence of nonspecific breakdown takes place at this stage. Nevertheless, a counter shock phase is recorded if the stressor continues (Nevid, 2009). This stage is characterized by increased heart beat rate, blood pressure, and alertness among others. On the other hand, resistance stage occurs when there is a reduction in the alarm reaction. This is where developmental adaptation takes place. Even with the stress is noted, at this stage, there is an immense attempt to maintain proper functioning of the body (Hesson & Olpin, 2013). In the last stage, exhaustion stage, if the organism is unable to get back into its normal status, the stage of exhaustion takes place. At this point, the initial characteristics of the alarm stage occur while there little effort to counter the stressor. Application of Selye theory to sleep disturbance It is apparent that sleep disturbances are connected to some stressors. Critically ill patients are susceptive to external factors that interacts the patient during the sleep (Berry, et al, 2005). For instance, environmental factors such as noise and light could be termed as sleep disturbance. It is apparent that noise is a stressor that causes sleep disturbance not only to sick persons, but also to health people. In fact, when there is noise around, one is not able to maintain the sleep as the nervous system is disturbed. This alarms the patient and forces him to be awake for as long as the stressor persists (Berry, et al, 2005). For some people, it is possible for them to resist the stressor and continue sleeping. This is mostly noted to people who for a long time are subjected to noise or people who live in a noisy place. If the individual is not able to cope with the situation, the condition of sleep disturbance becomes worse with little of resistance being applied. Light also may act as a stressor and could cause sleep disturbance. In most cases, light would keep patients awake and causes problems during the sleep. In fact, some people prefer sleeping in dark rooms. Critically ill patients require having enough rest and sleep. When subjected to light, they are not able to have a sound sleep. When light stuck eyes, a signal is sent to the nervous system, something that keeps the patient awake. In another dimension, when the patients interact with the patient, the patient is not able to have sound sleep because of the continued interruption from the nurse. In fact, some people have a fear of the nurse especially if they fear syringe. In this regard, it means that whenever the nurse is around the patient may not be able to have sound sleep as they fear that the nurse is just about to give them an injection. In addition, patient’s illness is also another major stressor that cannot be ignored. Some illnesses can cause a lot of discomforts not only during sleep, but also during other time (Berry, et al, 2005). For instance, some illnesses such as cancer are considered to cause pain to patients.