EVERY DAY
The discs settle
The discs between your vertebrae make up about a quarter of your spine's height. Through the day they can lose up to almost 2 cm of spinal height, then recover overnight.
Compare the changesStart
TRACKING HEIGHT THROUGH LIFE
Your height
is not fixed.
You are a little shorter at bedtime than when you got up.
Height changes on three timescales: through the day as the discs in your spine compress, over later life as bones and muscles change, and across generations as nutrition and living conditions improve.
≈ 2 cmlost by evening, back by morning
Compare the changesKeep in mind
- Daily: the discs
- Later life: a slow loss
- Generations: taller
- One body, three clocks
THE SHORT ANSWER
Three ways
height moves.
Small daily swings, a slow loss in later life,
and a big shift over a century.
LATER LIFE
A slow shrink
Measured repeatedly, people over 50 in England lost about 0.1 cm a year on average, with women losing height faster than men.
See the numbers
A CENTURY
Taller generations
Young adults in the UK are about 11 cm taller than a century earlier, a change researchers link mainly to nutrition and living conditions in childhood.
Why we grewHOW BIG IS EACH CHANGE?
Height changes,
side by side.
Pick a change to see its size. The bar shows how large it is compared with the others.
Figures from a Swiss MRI study of spinal discs, the English Longitudinal Study of Ageing, and the NCD Risk Factor Collaboration's 100-year height study.
TWO NUMBERS WORTH KNOWING
A century up,
a few centimetres down.
Britain's big gain in height,
and the small loss most of us make later.
≈ 11 cm
Rise in average height of UK men and women over a century
Based on 18-year-olds in 1914 and 2014. UK women moved from 57th to 38th tallest in the world, men from 36th to 31st.
100-YEAR STUDY · NCD-RISC, eLIFE 2016
2–4 cm
Typical height lost in later life
From repeated nurse measurements of people over 50. Declines in muscle mass and bone density are the likely mechanism.
AGEING STUDY · ELSA, ENGLAND
Sources: eLife, Dutch men and Latvian women tallest in world according to 100-year global height study (2016); Physical stature decline and the health status of the elderly population in England (ELSA).
MEASURING HEIGHT PROPERLY
Small changes need
careful measuring.
The RCPCH's measuring guidance for children shows why a tape against a wall is only a rough guide.
Step 1
Take shoes off
Shoes should be removed. From age 2, height is measured with a rigid rule with a T-piece or a stadiometer; younger children are measured lying down on a length board or mat.
Step 2
Note the date
The guidance says to record measurements and the date in ink. On growth charts, getting the age wrong is the most common plotting error.
Step 3
Mind the time of day
Because height varies through the day, researchers treat daily spinal compression as a source of measurement error. Comparing readings taken at similar times keeps the picture fairer.
Step 4
Read centiles correctly
A centile line shows the percentage of children expected to be below it. RCPCH says anyone who measures, plots or interprets the charts should be suitably trained, so questions about a child's growth belong with a health professional.
WHY GENERATIONS GREW
Nutrition, environment
and a plateau.
The 100-year study, led by Imperial College London with almost 800 scientists and the World Health Organization, says how tall we grow is strongly influenced by nutrition and environment, although genes also play a part. Better-nourished children living in better conditions tend to be taller.
The UK's rise has slowed: it is among the high-income countries whose average height has plateaued over the past 30 to 40 years, while Spain, Italy and many countries in Latin America and East Asia are still getting taller.
Questions
Questions on the way
Am I really taller in the morning?
Yes. The discs in your spine lose some height through the day under an upright posture and recover overnight. A Swiss MRI study notes this can reduce spinal height by up to almost 2 cm, about 1% of body height.
Do people shrink as they get older?
On average, yes. Repeated measurements of people over 50 in England found an average loss of about 0.1 cm a year, roughly 2 to 4 cm over the life course, with women affected more.
Why do we lose height in later life?
The ELSA researchers found declines in muscle mass and bone density are the likely mechanism.
How much taller are people in the UK than 100 years ago?
About 11 cm for both men and women, comparing 18-year-olds in 1914 with those in 2014, according to the NCD Risk Factor Collaboration study published in eLife.
How should a child's height be measured?
RCPCH guidance says to remove shoes and, from age 2, use a rigid rule with a T-piece or a stadiometer, then plot the result with the date on a UK-WHO growth chart.
Destination
Where the facts come from
- eLife: Dutch men and Latvian women tallest in world according to 100-year global height study (2016)
- Scientific Reports (2020): Diurnal T2-changes of the intervertebral discs of the entire spine (PMC)
- Economics and Human Biology: Physical stature decline and the health status of the elderly population in England (ELSA, PMC)
- RCPCH: UK-WHO growth charts, 2-18 years
- RCPCH: UK-WHO growth charts, guidance for health professionals
Updated