NIOSH Training for Nurses on Shift Work and Long Work Hours

Diseases and Long Hours (Continued)

Musculoskeletal Disorders

Eight studies with some controls for physical demands showed that long work hours increase the risk for musculoskeletal disorders (MSDs).⁸⁴ If you work long hours, you may be at higher risk for pain or discomfort in the back, knee, hip, foot, hand, arm, neck, and shoulder.

Researchers theorize that long work hours and MSDs could be linked through several mechanisms.^84,85

• Longer duration of work causes higher daily exposure to physical demands such as lifting and working in awkward postures.
• Stress leads to co-contraction^a of muscles, which increases loading on the spine and the risk for back pain.
• Impaired sleep shifts the immune system balance of T helper cells toward inflammation.
• Impaired sleep could lead to poorer coordination and body awareness.

^aSimultaneous contraction of agonist (driving) and antagonist (braking) muscles.