Sleep and Fatigue — Page 220, Lesson 353

I want to walk you through the section on sleep disorders and the effects of alcohol on sleep. This is important because as a professional pilot, your ability to manage sleep and recognise when something is wrong with your own or a colleague's sleep patterns is a direct safety issue. Let's start with Sleep and Alcohol. Many aircrew use alcohol as a way to help themselves fall asleep. However, I need you to understand exactly what is happening here. Alcohol is a non-selective central nervous system depressant. That means it suppresses activity throughout your entire central nervous system, not just in one area. While it may help you get to sleep initially, the sleep pattern you enter will not be normal. Specifically, REM sleep — the rapid eye movement stage where most dreaming occurs and which is critical for mental restoration — will be reduced considerably. Furthermore, you are likely to experience early waking, meaning you wake up before you have had sufficient rest. So while it feels like it helps, it actually degrades the quality of your sleep. Now, let's move into the Sleep Disorders you need to know about. First is Narcolepsy. This is a condition where a person has an inability to stop falling asleep, even when they are in sleep credit — meaning even when they have had enough sleep and are not sleep-deprived. Specialists believe this is associated with the brain's inability to distinguish between wakefulness and REM sleep. For aircrew, this is clearly undesirable because the sufferer may go to sleep at any time, even in a dangerous situation. Next is Apnoea. This is a cessation of breathing while asleep. It is quite a common condition, and normally the subject will either wake up or restart breathing after a short time. It becomes a more serious problem when the breathing stoppage lasts for up to a minute and the frequency of stoppages increases. When this happens, the frequent awakenings disturb the normal sleep pattern, and the individual may experience excessive daytime sleepiness. Other clinical problems may be involved, and medical advice should be sought. Then we have Sleepwalking, also known by its medical term Somnambulism. This condition, as well as talking in one's sleep, is more common in childhood but does occur later in life. It may happen more frequently in those operating irregular hours or those under some stress. The condition should not cause difficulty in healthy adults unless the sleepwalker is involved in an accident while away from their bed. Importantly, sleepwalking, like night terrors, happens during non-REM sleep. Finally, we have Insomnia, which is simply the term for difficulty in sleeping. It is divided into two types. The first is Clinical Insomnia. This describes the condition when a person has difficulty sleeping under normal, regular conditions that are in phase with the body's rhythms. In other words, it is an inability to sleep when the body's systems are actually calling for sleep. You must understand that clinical insomnia is rarely a disorder within itself. It is normally a symptom of another disorder. For this reason, the common symptomatic treatment with sleeping drugs or tranquillisers is inappropriate unless treatment for the underlying cause is also undertaken. The second type is Situational Insomnia. This is an inability to sleep due to disrupted work/rest patterns or circadian dysrhythmia — which is a disruption of your body's internal 24-hour clock. This often occurs when you are required to sleep but your brain and body are not in the sleeping phase. This condition is the one most frequently reported by aircrew.