Stress and fatigue in diving

Human behavior is influenced by several factors defined as “stressors.” These can originate from the individual’s psychophysical state and the external environment. In diving, it is crucial to understand how to react to stress in a controlled way to ensure safety and efficiency.

Impact of fatigue on divers

A state of extreme fatigue has several adverse effects on the mental and physical condition of divers:

  • Cognitive abilities: loss of flexibility in making decisions and reduced adaptability to changes in the situation. This can make the diver unable to react promptly to an emergency.
  • Motor activities: loss of coordination. The loss of dexterity can seriously compromise the ability to manage one’s diving equipment.
  • Communication skills: difficulty speaking and expressing complex concepts. In the briefing phase, a tired diver may not understand relevant parts of the information.
  • Sociability: tendency to isolate oneself and frequent irritability. The structure of the buddy system and team is compromised.
  • Physiological impact: increased sensitivity to decompression problems.

An isolated event of acute fatigue, such as sleep loss after travel or extreme physical activity, is usually resolved with a single rest period. If, on the other hand, the state of fatigue is prolonged for several days (3 or 4), then a single period of rest will no longer be sufficient. Still, it will be necessary to plan an adequate recovery interval. Diving operations must include rest periods as an integral part of the planning.

Good physical fitness, correct swimming techniques, and pre-dive rest are essential to avoid debilitating fatigue. In any case, we all have limits, and it is necessary to know how to recognize them so that diving always remains within safety parameters.

Stress and panic

As stress increases, the individual tends to focus more on what he considers to be the primary tasks, progressively neglecting the secondary tasks. For example, suppose a diver has to navigate in low visibility conditions. In that case, his attention will be focused on maintaining the correct direction, probably overlooking other activities not strictly related to navigation. This behavior can optimize mental resources for the most crucial task. However, the diver’s performance is compromised when the stress exceeds a certain critical level. If stress increases, “tunnel vision” develops with losing contact with the surrounding reality. The diver in the above example may be so preoccupied with maintaining the correct navigation direction that he ignores other vital parameters of the dive, such as maximum depth and breathing gas consumption.

The reaction to high levels of stress is defined as “Seyle’s General Adaptive Syndrome” and is characterized by four consecutive phases:

Stage 1: A sense of shock and surprise makes the individual unable to react; You are, literally, “frozen in fear.”

Phase 2: The individual reacts to the situation thanks to the release of specific hormones.

Stage 3: Energy reserves, both physical and mental, begin to be depleted.

Stage 4: At this stage, you are likely to make mistakes and cannot react further; the individual is exhausted.

When diving, the four phases follow one another in a short time, a few minutes, and a diver exposed to high-stress loads will soon become incapable of further reactions. For this reason, it is necessary to intervene promptly, and this is possible only with adequate preparation, experience, and excellent control of emergency procedures.

Under conditions of extreme stress, the diver should adopt a procedure consisting of the following points:

  • Stop: Temporarily stop your actions.
  • Breathing: Maintain control of your breathing to conserve the breathing gas and as a relaxation technique.
  • Thinking: Rationally identify the problem and look for a suitable solution.
  • Take action: implement the solution identified in the previous point.

It is essential to focus on the practical solution to the problem before it is too late. Almost any situation can be solved in the water, alone or with the help of your dive buddy, if you maintain sufficient mental clarity.

If stress is not controlled, it can degenerate into panic, causing a breakdown in logical thinking. The individual cannot act rationally by becoming inactive (passive panic) or performing uncontrolled, irrational, and often dangerous actions for himself and others (active panic). This situation is hazardous for a diver with potentially fatal results for two main reasons:

  • Panic causes increased breathing that also becomes inefficient, triggering hypercapnia (increased concentration of carbon dioxide in the blood) and a feeling of “air hunger.” Consequently, the panicked diver often rejects the regulator and tries to rise to the surface uncontrolled.
  •  Overactivity of the sympathetic nervous system leads to a sharp acceleration of the heartbeat, a marked increase in blood sugar, and, in extreme cases, can cause cardiac arrest. 

Fatigue and stress are, therefore, elements to be considered seriously when planning our diving activity because their impact on physical and mental performance is high and, if not adequately controlled, can lead to dangerous situations