It has been found that drivers who cover over 25,000 miles a year average 22 days off with sickness, compared with just over 3 days for low mileage drivers. The underlying cause may not be the actual number of miles driven or even the vibration the long-distance driver is exposed to. Indeed, train drivers, who are exposed to less vibration than road vehicle drivers, are twice as likely to report low back pain. The main causal factor appears to be long-duration sitting, for which our bodies were not designed. It has been found that people whose occupations involve sitting for long durations can suffer almost as much lower back pain as people whose job involves frequent lifting.

The pain seems to originate from ruptures to the discs separating the bones of the back. These ruptures can be quite small, so they do not impinge on any nerve roots and thus do not directly cause the pain. However, they can lead to misalignment of the articulating joints, which can result in pain. This may also lead to additional pain due to muscle spasm as a result of the original pain. Long-term sitting has two effects that can result in these small disc ruptures.

Firstly, because the discs do not have a blood supply, they are dependent on movements of the spine to ‘squeeze’ nutrients in and out. These movements may not occur when sitting for long periods, causing the discs to become deprived of nutrients.

Secondly, the bones of the spine are held in position by ligaments connected between each bone. These are flexible but very strong fibers that stretch a small amount under tension. When relaxed, however, they do not recover their original length for several hours. Driving with a slumped posture will place the ligaments at the rear of the spine in tension. After a few hours, the joints of the back become unstable, leaving the discs vulnerable to rupture if the back is twisted, such as when getting out of the vehicle or lifting loads.

Reducing the risks of back pain

This explanation of the causes leads to two primary preventative measures: reducing the duration of sitting and ensuring a good driving posture that avoids slumping in the seat.

Reduce the duration of sitting

The service bus driver may have opportunities to get out of the driving seat and take mini exercise breaks during a shift. Ideally, they should be encouraged to do so at every opportunity where the bus will be stationary for a few minutes. The driver should be encouraged to leave the vehicle and walk around.