Fatigue is expressed through a feeling of overtired, with low energy and a strong desire to sleep that interferes with normal daily activities. In a work context, fatigue is a state of mental and/or physical exhaustion which reduces a person’s ability to perform work safely and effectively. The causes of fatigue include:

1. Environmental conditions: Working in harsh and uncomfortable conditions can contribute to fatigue.
2. Sleep deprivation: Most of us need an average of 7 to 9 hours of sleep each night to fully recuperate from a regular day’s work, both physically and mentally.
3. Changing work schedules: Work schedules which limit the time workers can physically and mentally recover from work may cause fatigue
4. Health factors: A worker’s lifestyle, family responsibilities, health (e.g. insomnia, sleep apnea, some medication.