What is Fatigue?

Fatigue is the state of feeling very tired, weary or sleepy resulting from insufficient sleep, prolonged mental or physical work, or extended periods of stress or anxiety. Boring or repetitive tasks can intensify feelings of fatigue. Fatigue can be described as either an acute or ongoing state of tiredness that leads to mental or physical exhaustion and prevents people from functioning within normal boundaries. All of these have obvious implications for workplace and public safety. Fatigue can also have long-term effects on health.

Effects of Fatigue

The effects of fatigue on health and workplace performance can be short-term as well as long-term. Short-term effects on an individual include impaired work performance, such as:

• reduced decision making abilities
• reduced communication skills
• reduced productivity/performance,
• reduced ability to handle stress on the job
• reduced reaction time, both in speed and thought (a few studies have shown this effect as similar to being legally drunk)
• loss of memory or the ability to recall details
• unable to stay awake (e.g. falling asleep while operating machinery or driving a vehicle)
• increased forgetfulness
• increased errors in judgement
• increased sick time, absenteeism, rate of turnover
• increased accident rates

Causes of Fatigue

There are many, many causes of fatigue. Work-related factors may include long work hours, long hours of physical or mental activity, insufficient break time between shifts, inadequate rest, excessive stress or a combination of these factors. Sometimes, a sleep disorder may cause fatigue. These conditions include insomnia, sleep apnea, restless legs syndrome and narcolepsy. Ask your doctor or health professional for more information about these disorders.

Substances such as nicotine, caffeine, and alcohol can also affect your quality of sleep. Caffeine can remain in the body for about 3 to 7 hours and may affect your ability to sleep. Alcohol may shorten the time it takes to fall asleep, but it can disrupt you later in the night. Nicotine can also disrupt sleep and reduce total sleep time. Other substances such as over-the-counter medications or prescriptions may also affect sleep. For example, long-acting benzodiazepines (drugs used to relieve anxiety or insomnia) may contribute to daytime sleepiness.

How Much Sleep Do People Need?

It varies, but on average studies say we need at least 7.5 to 8.5 hours every night. Studies have reported that most night workers get about 5 to 7 hours less sleep per week than day shift workers. (And in an ironic twist, you can accumulate a sleep "debt", but not a surplus!) Humans follow an "internal" or "biological clock" cycle of sleep, wakefulness, and alertness. Although these circadian rhythms are influenced by external clues such as the sun setting and rising, it is the brain that sets your pattern. Most cycles are 23-25 hours long and there are natural dips or periods when you feel tired or less alert - even for those who are well-rested.

Tips on Preventing Fatigue

• Eat a healthy and balanced diet.
• Try to drink six to eight 8-oz. glasses of water every day.
• Eating six small meals rather than three large ones can help regulate your blood sugar and in turn, regulate your energy supply
• Exercise every day. Even if you can't commit to a full hour at the gym every morning, find a way to work exercise into your daily routine. Regular exercise can help decrease fatigue and even help you sleep better.
• Maintain a consistent sleep schedule. Getting adequate and regular sleep is one of the most important steps you can take in preventing fatigue so try to go to bed and wake up at the same time each day, even on weekends, and avoid oversleeping.
• Identify sources of stress and take steps to cope with them. The body's emotional response to stress uses a tremendous amount of energy, leading to persistent fatigue, reports Harvard Medical School. It may be impossible to live a stress-free life, but learning to deal with it can help you fight fatigue. Consider relaxation techniques like meditation, tai chi, yoga, massage, aromatherapy and progressive muscle relaxation.

Additional Warnings

• If you've made major improvements to your lifestyle but are still feeling fatigued, see a doctor. Fatigue can be a symptom of many other health conditions.
• Avoid caffeinated drinks such as coffee, tea and soda; they provide a temporary supply of energy before leaving you feeling even more tired than before.
• Fatigue compared with blood alcohol content:
  • Being awake for 17 hours impairs performance to the same level as having a 0.05 blood alcohol content.
  • Being awake for 20 hours impairs performance to the same level as having a 0.1 blood alcohol content.

OHS Laws and Preventing Fatigue

OHS laws are designed to ensure the health and safety of everyone in the workplace. Employers have a duty to provide, so far as is reasonably practicable, a working environment that is safe and without risks to the health of workers. 

Workers have a duty to take reasonable care for their own health and safety and the health and safety of others in the workplace. Workers also have a duty to follow procedures and cooperate with actions their employer takes to comply with OHS laws.

Compiled with information from the Canadian Centre for Occupational Health & Safety and WorkCover NSW.