Many pharmacists are required to work on their feet for long hours, but that can have serious health consequences similar to sitting.

Previous research has linked prolonged standing in the workplace to reports of short-term fatigue, backache, and leg muscle pain. Now, there is evidence of a long-term effect on muscles, which could contribute to back disorders.

Researchers recently examined 26 individuals from 2 different age groups—18 to 30 years, and 50 to 65 years—who all simulated a standing workday for 5 hours, including 5-minute breaks and a 30-minute lunch.

Participants spent the workday performing varying tasks, such as working at a computer, reading, and playing games. They received a rest break at the end of the first, third, and fourth 55-minute periods of standing. They were instructed not to do anything that would be a “forceful exertion,” and they were all provided the same type of sports shoe to wear.

The younger group also participated in a control day, which mostly involved sitting at the computer.

One of the methods the researchers used to measure muscle fatigue was electrically induced muscle twitches, or muscle twitch force (MTF). Electrodes on the participants’ skin and a strain gauge force transducer measured the twitch force caused by electrical stimulation of the gastrocnemius-soleus and tibialis anterior muscles. The researchers picked this method based on previous studies that used MTF to measure the long-term effects of fatigue.

The results of the MTF tests showed a “significant fatigue effect” from the prolonged standing work. This persisted for more than 30 minutes after the end of the simulated workday.

Another measure of fatigue that the researchers employed was the participants’ subjective evaluations of their own discomfort. They were asked to rate their level of discomfort on a scale of 0 to 10 for 11 areas on their body, including the lower back, lower leg, ankle, and foot.  

The subjects reported more discomfort on the standing days immediately after the end of the 5-hour workday, but this feeling vanished after a 30-minute rest period.

The researchers placed more weight on the objective MTF measures, however, which showed a more lasting effect on muscles.

“Absence of perception does not mean an absence of significant fatigue,” they asserted.

Because they found no evidence of muscle fatigue after 2 hours of standing with a 5-minute seated rest in between, the researchers suggested that this standing duration would be acceptable in a workplace, but 5 hours of standing would pose health risks.

“Current work schedules for standing work may not be adequate for preventing fatigue accumulation, and this long-lasting muscle fatigue may contribute to musculoskeletal disorders and back pain,” study author and PhD candidate María Gabriela García concluded in a press release.

The researchers highlighted the fact that many health care personnel, in particular, spend a large portion of their day standing.

The results of their study were published in Human Factors.