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cope with a helicopter crash after completing the course. A similar proportion, 78, reported an increased confidence in flying. The authors considered that coping was
developed through repetition and controlled action in this unusual situation. During the investigation following the helicopter crash near the Cormorant Alpha platform
in the North Sea two of the survivors were interviewed. Both considered that the helicopter escape and survival course that they had completed prior to the incident had
contributed to their survival, despite the helicopter simulator bearing little or no resemblance to the passenger cabin of [a] real helicopter AAIB, 1993. This suggests
that the benefits of training for these individuals may have come from a level of preparedness and knowledge about what to expect. Whilst the helicopter simulator was
not considered to have high fidelity with a real cabin, it was sufficient for those individuals to learn the procedures that helped them make their escape in the real emergency
situation.
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4.0 REVIEW OF STRESS
4.1 STRESS - CONCEPT, RESPONSES AND COPING
The term stress has many different meanings and can be used in a number of ways. Stress is generally used to describe the harmful effects of an environmental demand on
the body. It can be split down into a number of components: 1 stress stimuli or stressors; 2 the processing systems during the demanding period or event; 3 stress
responses following the demanding period or event Ursin and Olff, 1993. When considering stress during HUET training we need to consider all three components: the
factors causing stress; what happens during training and how this affects the individual and their subjective experience; and the consequences of this experience, on both short-
term and long-term health. Stressors may include prior perceptions of what might happen during training, the fear of being underwater and not being able to breath, the fear of being
trapped and unable to escape from the helicopter simulator, peer pressure and the ego- threats of not being able to cope. The level of control an individual has over a particular
situation or event is known to influence psychophysiological function e.g. Breier et al, 1987 with lack of control acting as a stressor.
The human body responds to stressors in a number of ways that allow the body to cope with the demands of the situation. The physiological response involves a general arousal
or activation of the central nervous system. This initial response has been described as the fright, fight, flight reaction, resulting from stimulation of the sympathetic nervous
system and the release of adrenalin. Heart rate and blood pressure increase, breathing rate increases, muscle blood flow increases, and in extreme cases, perspiration and pallor
may be observed. These responses prepare the body for action. This condition is associated with the subjective experience of anxiety, an emotional state characterised by
feelings of apprehension and tension that can interfere with the individuals ability to perform tasks.
Later stress responses include activation of the hypothalamus-pituitary-adrenal HPA axis and the consequent release of glucocorticoid hormones such as cortisol. These
hormones bring about the release of energy, with an increased production of glucose and reduced uptake by tissues, with the release of free fatty acids from adipose tissue and
stimulation of protein breakdown. Glucocorticoids are also thought to suppress immune functions and may therefore have effects on long-term health.
Whilst mild levels of activation may be experienced by the individual as a pleasant thrill, high levels of activation can be experienced as unpleasant and stressful, depending upon
the individual and the situation Ursin and Olff, 1993. The level of activation, and of anxiety experienced is thus important. Above the optimum level, performance may be
impaired. It is also important to note that individuals adapt to stressful situations over time. According to Hytten 1989 when fear is confronted and coped with at one intensity,
it is probable that one will cope with a new fear-provoking situation of greater intensity. Thus, coping with a training situation allows the individual to develop coping mechanisms
and thus manage a real life-threatening event more effectively. In real emergencies, victims show a range of behaviours in response to the threat. Muir
1999 has described a number of behavioural responses experienced by passengers involved in transport accidents. These include the following:
Fear
The two reactions to fear are fight and flight. The most frequently reported reaction in an accident is flight, providing the impetus to
rapidly escape.
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Anxiety This is experienced by the majority of passengers in an emergency
situation and may impair their performance of actions that are novel and difficult HUET training aims to reduce the novelty of the
situation.
Disorientation In a helicopter this results from a reduction in visibility, in-rushing
water and the change in orientation following capsize. This will increase levels of anxiety and may result in a failure to locate an exit.
Depersonalisation Witness reports from life-threatening events indicate that the passage of time seems to slow. This is thought to be as a result of people
detaching themselves from the actual situation in order to think and respond more effectively.
Panic It is thought that true instances of panic amongst passengers in
accidents are rare and are usually due to feelings of being confined. Behaviour in accidents that might be regarded as panic can be
interpreted as a rapid series of rational responses.
Inaction It is thought that between 10 and 25 of people do little or nothing to
escape from danger. Evidence from accidents seems to indicate that there are many more instances of behavioural inaction than panic.
Inaction or freezing is of great concern in the helicopter emergency situation. This may add to the anxiety of an individual who is not seated next to an exit, facing the prospect
that the person seated next to the exit will not make a rapid escape and will effectively block the exit. Leach 2004 suggested that freezing could be accounted for by time
constraints on the cognitive processing of information in a rapidly unfolding, real-time environment.
The main aims of training must therefore be to reduce the likelihood of these behaviours. This can be achieved through familiarisation with likely scenarios, familiarisation with the
equipment that might be used and the procedures that must be followed, thereby generating confidence, coping skills and a positive outcome expectancy.
4.2
EFFECTS OF PSYCHOLOGICAL AND PHYSIOLOGICAL STRESS ON PERFORMANCE
Performance in a threatening situation will depend upon the level of perceived threat, the coping abilities of the individual and the resultant level of stress experienced. It has been
reported that lack of control over a stress condition can result in higher levels of reported helplessness, tension, anxiety and physiological activation of the HPA axis Breier et al,
1987. Whilst low levels of anxiety can be experienced without any significant decrement in performance see Idzikowski Baddeley, 1983 there is a large amount of literature
showing that higher levels of stress result in cortisol release that is known to affect cognitive function.
Much of the focus on the effects of stress on performance has thus focussed on the effects of cortisol on the body and its role in the stress response. Cortisol is known to be
produced in response to both psychological and physiological stressors, although there is a wide variability in cortisol response between individuals. Cortisol levels have been
linked both to defence and to coping see Harris, 1995 for review. It is also known that glucocorticoids such as cortisol, secreted in response to stress,
have an affect on cognitive performance by impairing declarative memory recall, defined as the conscious recollection of learned material Elzinga et al, 2005; Kirschbaum et al,
