Guess what? Instead of babying our backs, we may have to be sure to get plenty of running, jogging, or brisk walking to make our backs stronger - specifically, to strengthen the discs in our spines. Once again, a study finds that exercise (here the upright exercise of running, jogging, or fast walking) has benefits. The authors of the study state that the research results go against conventional medical wisdom - that instead of weakening the spine (conventional view), those people who run or jog many miles each week may actually be strengthening the discs of the spine. And maybe... the researchers suggest (though it needs to be verified first)... in the future, we may get medical prescriptions to jog or fast walk a certain number of miles each week to strengthen the discs in our spines.
The study found that the ideal speed for the spine health was a slow run or a fast walk (4 miles per hour). Specifically fast walking and slow running at about 2 meters per second (m/s) appeared the most beneficial. However, high impact exercises, or aerobic exercises, slower walking, or no exercise did not have these benefits.
Until now, discs had been considered a "slow tissue," thought to take much longer to respond to exercise than muscle. And that with age and use the discs degenerate, and nothing could really be done to improve them. But the study's findings suggest that exercise can benefit and strengthen the intervertebral disc (IVD) in the spine. As researcher Dr. Belavy said: "It's also important to reduce the amount of time spent in static postures, such as sitting or even standing still. Even going for a walk during a break at work, or choosing to take the stairs rather than the elevator is good for the discs, as well as for overall back health."
From NY Times: Why Running May Be Good for Your Back
People who regularly run or walk briskly appear to have healthier discs in their spines than people who do not exercise, according to one of the first studies to closely examine links between movement and disc health. The findings refute a widely held belief that activities like running might overtax the spine and indicate that, instead, they make it sturdier. The human spine is a complicated mechanism, composed of vertebral bones cushioned between intervertebral discs. These discs, shaped like tiny whoopee cushions, contain a viscous fluid that compresses and absorbs pressure during movement, keeping the back in good working form. With age, disease or injury, spinal discs can degenerate and bulge, resulting in back pain, which can be debilitating.
There were tantalizing hints in animal studies, however, that this idea could be out of date. ....So for the new study, which was published in April in Scientific Reports, researchers at Deakin University in Australia and other institutions decided to examine the backs of people who run and others who do not. Eventually they recruited 79 adult men and women, two-thirds of whom said that they were runners. Some of these told the researchers that they covered more than 30 miles (about 50 kilometers) a week in training. The researchers designated these as the “long-distance” group. The others said that they ran between 12 and 25 miles a week. All had been training for at least five years. The final group rarely exercised at all.
To ensure that people’s reported activity levels were accurate, the researchers asked their volunteers to wear accelerometers for a week. Then they scanned everyone’s spines, using a sophisticated type of M.R.I. that precisely measures the size and liquidity of each disc. And they found differences. In general, the runners’ discs were larger and contained more fluid than the discs of the men and women who did not exercise. Since both greater size and increased levels of internal fluid indicate better disc health, the runners harbored fundamentally healthier spines than the people who were sedentary, says Daniel Belavy, a professor of physical activity at Deakin University who led the study. Interestingly, mileage barely mattered.