First thing in the morning, lean against a doorframe, mark the top of your head, then take another measurement before going to bed. You will likely find you are a bit shorter at night. Not enough to see in the mirror, but often by something near a centimetre, and sometimes even more.<\/p>\n
A lot of that height is regained while you sleep.<\/p>\n
The strange thing is how unnoticed it remains. You could lose the thickness of a stacked coin from your height throughout a day and not realize it, as the change is spread along your spine’s length. Researchers have observed this for centuries. An MRI study presented to the Radiological Society of North America<\/a> highlights that the daily fluctuation in human height has been acknowledged since 1726, documenting an average shift of about 17 millimeters.<\/p>\n A significant portion of the change is due to the discs located between the spinal bones, the pliable cushions that separate the vertebrae and assist in load distribution. Each disc consists of a robust outer ring encasing a softer, water-laden core.<\/p>\n Throughout the day, while you are standing, walking, or sitting straight, the weight on the spine compresses these tissues and expels some fluid from them. When you lie down and alleviate much of that vertical pressure, the fluid gradually reenters. The discs expand once more, aiding in the height you recuperate overnight.<\/p>\n Dr. Rey Bosita, a spine surgeon at the Texas Back Institute, explains the fundamental concept clearly. \u201cIn a human spine, the discs are soft: they can get bigger and smaller and they have elastic properties,\u201d<\/a> he states. Bone does not noticeably shorten throughout a typical day. The quantifiable change mainly arises from soft tissues in the spinal column reacting to pressure.<\/p>\n The fluid movement can be considerable. In a small MRI study by Botsford and colleagues<\/a>, eight men were scanned after lying down for six hours and again after a simulated daytime-loading period of standing and sitting. Across the three lowest lumbar discs, the average volume decreased by 16.2 percent, with individual levels showing reductions nearing one-fifth.<\/p>\n This study did not document a regular morning-to-evening routine, and it involved only a small cohort. Nonetheless, it demonstrates how much the spinal disc volume can alter when transitioning from an unloaded to a loaded state. Minor alterations across multiple discs can accumulate to a difference substantial enough to be measurable with a ruler.<\/p>\n You do not experience height loss at a constant pace throughout the day. A large portion of the reduction takes place shortly after you rise.<\/p>\nWhat the discs are truly doing<\/h2>\n
Why most of the reduction occurs early<\/h2>\n