Why we are taller in the morning than in the evening?

Answer 1

We are taller in the morning than in the evening because during normal activities during the day the cartilage in our knees and other areas slowly compress, but when you go to sleep and rest the cartilage goes back to normal. On average we are about 1cm taller the morning than in the evening.

The other component to this phenomenon is that the joint capsules loose some of their synovial fluid and the connective tissues around the joints tend to become compressed throughout the day from activity and trying to counter the affects of gravity.

Also, the discs of the spine do the same thing. During the night, they resorb more fluid making them thicker and the person taller. While walking or being upright during the day, they slowly lose some of this fluid and become thinner.

Answer 2

We are taller in the morning than in the evening because the center of our gravity is higher in the morning.

Movement of the center of gravity:

All the skeletal muscles of the body can Isometrically contract and relax as a single unit called Unified Skeletal Muscle or USM.

We can Isometrically contract our USM towards the head or feet. Contraction of the USM towards our head moves our center of gravity higher, relaxes the inter vertebral discs, reduces the curvatures of the spine and thus increases our height. Contraction towards the feet lowers our center of gravity, compresses our inter vertebral discs and increase the curvatures of our spine.

Voluntary control of height:

We can vary our height, within limits, at will if we have control over our skeletal muscular system. We can be taller at midnight if we wish to and be dwarfer in the morning.

Normal variation of height:

Normally we are more active in the morning and thus our center of gravity would be at a higher level in the evening to enhance our mobility.

The unorthodox explanation:

This explanation may look somewhat different form conventionally held view. The reason is that in all scientific experiments on human body our mind and 'I' are bypassed. Scientifically 'I' doesn't exist. Mind too is supposed to be abstract.

For the above reason inter vertebral discs are supposed to get compressed in the evening. However, no mention is made of what structure compresses them.

Answer 3

In the morning when you first get up. By the end of the day some people are up to an inch (25mm) shorter.