20-12-2012, 11:11 AM
SHIFT WORK
SHIFT WORK.ppt (Size: 3.91 MB / Downloads: 34)
INTRODUCTION
Shift work usually means regularly scheduled work conducted outside of the normal daytime working hours of 7:00a.m to 6:00p.m and includes:
Permanent night shifts, or other permanent shifts thatextend into the evening or night (such as afternoon and evening shifts), or begin before 6:00 A.M.
Variable or rotating shifts that change work times fromday to evening or day to night. The change may occur weekly or monthly.
The body has a 24 hour ‘biological clock’ (known as the circadian rhythm) that tells it when to sleep and when to wake up. Sunlight and darkness regulate this clock.(PICTURE OF THAT CLOCK)
Normally, darkness triggers changes in the body that lead to sleep. When falling asleep, the body’s blood pressure, heart rate, breathing rate and temperature drop. Digestion also slows.
Certain repair and maintenance processes occur during a phase of sleep known as delta sleep. It takes the body some time to reach delta sleep. Subsequent phases of sleep are important to psychological well-being.
Working during normal sleep hours affects the body's ability to digest food, rest, restore and repair itself and may affect a person’s sense of well-being
What are the HAZARDS
Problems associated with shift work can include:
Health hazards
Family and social issues
Safety hazards
HEALTH HAZARDS
Disrupted sleep and eating patterns interfere with digestion.
These disruptions can result in sleep and stress-related disorders and may affect the cardiovascular system.
Shift work often involves working in excess of 8 hours. These extended shifts can expose workers to more chemical and biological substances, noise, vibration and temperature extremes.
GASTROINTESTINAL PROBLEMS
Gastrointestinal problems, particularly ulcers, are more common among shift workers. Factors that may contribute to these problems include the following:
Consumption of night time snacks in addition to daytime meals.
Eat at night when digestion and other body functions are slowed down.
Consuming less nutritious foods on night shifts containing high fat content.
Drinking more coffee to stay alert at night. Heavy coffee consumption increases the risk of developing ulcers.
PERFORMANCE
Performing tasks that require alertness may be worse at night, when workers' bodies are prepared for sleep Performance levels appear to be lowest between 3:30 A.M and 5:30 P.M.
An accumulated sleep deficit from prolonged shift work can decrease a worker's level of performance and alertness.
Working extended shifts can also cause poor performance and decreased alertness. Performance deteriorates on extended work that is physically and mentally demanding.
Perception and decision-making ability may also be affected on extended shifts.
SHIFT SCHEDULING
Concept of compressed work week: These shifts usually involve three to four days of 10 to 12 hour shifts. It provides more time between shift schedules and more opportunities for family and social activities.
But they increase fatigue and decrease performance at the end of shifts.
Also extend worker’s daily exposure to chemical, biological and physical hazards.
Permanent afternoon, evening or night shifts: - These shifts allow workers time to adjust, but are disruptive to their social lives and may also accumulate a greater sleep deficit.