Fatigue is more than just feeling tired – it is a state of physical and mental exhaustion, which results in the loss of alertness.

This loss of alertness is accompanied by poor judgement, slower reaction time, and impaired coordination and decision making.

Causes of fatigue

The three main causes of fatigue are:

  1. Sleep loss – this is the most commonly known cause of fatigue. Different individuals require different levels of sleep, although the average is 7 to 8 hours of sleep a day. If you do not get a full night’s sleep, it is likely to cause fatigue, and this can build up over time if your sleep continues to be restricted.
  2. Circadian rhythms – everybody has a built-in body clock in the brain that biologically determines when they will feel sleepy. These circadian rhythms programme us to feel at our most sleepy between 3am and 5am, and between 3pm and 5pm. Our circadian rhythm of sleep is regulated by the hormone melatonin. A person with a normal sleep-wake cycle has melatonin released at night, coordinating mental and physical systems throughout the body.

    Circadian rhythms
    Diagram of a clock showing the times of day when body temperature, alertness, reaction time and melatonin secretion are highest.
  3. Time spent driving and working – research shows that the longer people spend driving without a break, the greater their level of fatigue. Also, the time spent in other activities such as work, school, and so on, can increase fatigue and affect subsequent driving.

Fatigue can also be caused by a number of contributing factors in the workplace or a person’s private life. These may include:

  • long, difficult or strenuous work
  • physical requirements of the job
  • irregular and unpredictable working hours
  • lack of quality sleep
  • mental stimulation of the job
  • poor work ventilation, lighting and design
  • working environment
  • constant concentration on a fixed or moving point
  • shift work
  • excessive work schedules
  • working more than one job.

Early signs of fatigue

People often experience these early symptoms of fatigue:

  • nodding off or constant yawning, a drowsy relaxed feeling or falling asleep at work
  • difficulty keeping eyes open or blurred vision
  • feeling spacey or fuzzy brain, wandering or disconnected thoughts, daydreaming, lack of concentration
  • clumsiness, slowed reflexes and responses
  • making more mistakes, increased errors
  • trouble remembering things, short term memory problems
  • feeling grumpy, moodiness
  • headaches or dizziness.

Tips for getting good sleep

Our bodies need seven to eight hours continuous sleep each night. If you get less than this you will build up a ‘sleep debt’. You may be ok for a couple of days or nights, but it will catch up with you and you’ll need a good long sleep to pay back the ‘debt’.

Losing two hours sleep per night for four days or nights will make you nearly as tired as losing one whole night of sleep. Such sleep loss greatly increases the dangers of a workplace-related accident or road crash.

Tips for getting good sleep:

  • Avoid stimulants. Tea, coffee and smoking in the evenings can disrupt your natural sleep patterns.
  • Don’t over-indulge. Too much food or alcohol, just before bedtime, can interrupt sleep. Alcohol may help you fall asleep initially but will disturb your sleep later on in the night.
  • Your bedroom should provide a restful place for sleep. It should be cool, dark and quiet. Consider removing things that will keep you awake, such as the TV and radio.
  • Try to get to bed at the same time every night – weekends included. Doing the same things each night just before bed prepares your body for sleep.
  • Try to relax before going to bed. Have a warm bath, listen to some quiet music, do some mindfulness or yoga. All help to relax both the mind and body.
  • Don’t lie in bed worrying about getting to sleep. If you can’t drop off in a short while, then get up and do something you find relaxing until you feel sleepy again – then go back to bed.
  • Deal with worries by making a list of what needs to be done the next day.
  • Try to get up at the same time every morning, irrespective of whatever time you eventually fell asleep that night. A constant rising time helps to reset the body’s own natural clock regulating sleep and wakefulness.
  • Although regular exercise will help you to relieve the stress of the day, avoid exercising too close to bedtime or you may find it difficult to sleep.