According to the University of Maryland Medical Center, back pain is a condition that leaves 2.4 million Americans chronically disabled and 2.4 million temporarily disabled, ranking as the second most common reason why Americans go to the doctor. Standing on your feet for 25 minutes a day could potentially lead to a lifetime of lower back pain, but could reduce your risk of hip fracture, according to a recent study.

A McGill University study in Canada revealed that just 25 minutes of standing may cause your lower spine to slump and pull on ligaments and muscles that can cause aching, fatigue, and even varicose veins. A team of researchers from the university asked 18 participants to stand up on folding boxes as the stiffness of their back muscles as well as the blood flow in their lower body were monitored.

After the participants stood on the boxes for 25 minutes, the researchers found that all of the 18 participants were experiencing muscular stiffness in their lower back, according to Dr. Julie Cote, an associate professor of biomechanics and ergonomics at the university. Some of the participants reportedly experienced muscle stiffness as soon as they stood on the boxes. "Some people had stiffness almost from the outset - so it seems that some people are unlucky and for some reason their physiology makes them more prone to stiffness when they stand,” said Cote, the Daily Mail reports.

Cote describes the muscle stiffness as if “the lower back goes to sleep and forgets how to protect itself from damage.” If the lower back is stiff, people are less inclined to use it, which could make the muscles weaker and leave them susceptible to injury.

Cote and her research team also found blood pooling, or minimal to no circulation of blood, in the participants’ legs after just 15 minutes of standing. Blood pooling may lead to bulging veins and aching — signs of varicose veins. These veins are typically found on a person’s legs and feet because standing and walking upright increases the pressure in the veins of the lower body, according to the Mayo Clinic. Varicose veins affect half of people 50 years and older.

“I see a lot of hairdressers, policemen, and teachers - people who spend a long time on their feet in the course of their work every day. I suspect that if you have a genetic susceptibility to varicose veins then standing up for long periods may speed up their formation and make them feel worse,” said Eddie Chaloner, a consultant vascular surgeon at the Radiance Health clinic, to the Daily Mail.

While standing for prolonged periods of time may lead to a lifetime of back pain, it can also lower the risk of hip fracture due to the great amount of time spent on your feet. Hip fractures typically occur due to factors that weaken bone strength, in combination with the impact of a fall. According to the American Academy of Orthopaedic Surgeons, bone strength starts to decrease as people age, leaving elderly men and women susceptible to osteoporosis. Standing can act as a protective factor as it may help prevent bone loss by maintaining strength and balance.

To have a good balance of sitting and standing, it is important to know how long you should sit and how long you should stand. For those who have a profession that requires long periods of standing, Professor Karen Messing, an ergonomist from the biological sciences department at Quebec University, has some helpful tips. “Really, they need to sit down for around 6 percent or more of their working day to avoid problems,” she told the Daily Mail.

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