Why is simply standing up so good for us?

Without realizing it standing exercises many parts of our body. Our leg muscles are constantly reacting to keep us balanced. Our brain is working to process visual and physical cues to keep us vertical. Our core is strengthened.
If you want more of a hidden workout try standing on one foot.and alternating.

Here is a link to a recent article in the BBC News regarding the health benefits of standing. How much better is standing up than sitting?

It covers the results of an experiment conducted where a group of people were asked to stand at least 3–4 hours more a day. Not only did their blood glucose levels drop more rapidly after a meal, it was discovered that they were burning more calories. One woman said that her arthritis symptoms were not as bad.

So, by standing up more, it helps prevent heart disease, diabetes, and obesity.

My brother retired from his career as a railroad engineer. Now my brother is thin and very fit because he’s been physically active for his entire life. Back when he was working he told me of the inordinate number of locomotive engineers suffering from prostate problems due (it was suspected) of having careers demanding prolonged sitting. I can testify from personal experience that as I grow older, it takes considerably less time of no physical activity for things to begin shutting down or withering away than it did in my youth. In fact several hours of sitting is all that is required for parts in my legs to begin complaining upon standing. So far, things return to “normal” with a little walking around, and climbing the stairs is all it takes to bring me “back”. But I’m paying attention to the treacheries involved with growing old, and shudder at the probable consequences of forced inactivity.

I suffered from a sciatic nerve condition recently in which I experienced unrelenting pain in my left leg. It left me unable to walk for several months.

During the course of physical therapy, I began to understand just how much poor posture contributed to lower back pain and my sciatic nerve condition. Not surprising, then, that when I started making myself stand up straight and used aids to encourage me to SIT up straight, the pain in my lower back and leg disappeared.

There’s something about poor posture that stresses nerve endings and damages the spinal column to the point of creating severe physical problems. So even now that I’m mobile and pain free, I remain especially mindful of my posture to prevent reoccurrence of that horrible pain.