Standing five hours a day contributes lower-limb muscle fatigue, a small study concluded, and may raise the risk for long-term back pain and musculoskeletal disorders, according to WedMD’s HealthDay.

Study authors report almost half of all workers worldwide spend more than three-quarters of their workday standing.

Two hours of standing on the job is not associated with problems, but "a longer period is likely to have detrimental effects," said one of the study researchers.

Investigators focused on 14 men and 12 women. Half were between 18 and 30 years old, and half between 50 and 65. Replicating a shift at a manufacturing plant, all were asked to simulate light tasks while standing at a workbench for five hours with five-minute rest breaks and one half-hour lunch break.

Regardless of age or gender, participants were equally likely to experience significant fatigue at the end of the work day. Because the study was small and of very limited duration, it doesn't prove that a job that requires prolonged standing will harm one’s health, the study noted.

Regular stretching exercises and "perhaps the incorporation of specific breaks, work rotation or the use of more dynamic activities could alleviate the effects of long-term fatigue," the researcher said. Alternating seated and standing work is also beneficial, she said, "as it alleviates both the issues with prolonged sitting and prolonged standing."

In addition to routine breaks to get the blood moving, ergonomics comes into play: work stations should be set at the proper height and distance from workers.