The main factor that influences a person’s height is their genetic makeup. However, many other factors can influence height during development, including nutrition, hormones, activity levels, and medical conditions.
Scientists believe that genetic makeup, or DNA, is responsible for about 80% of a person’s height. This means, for instance, that tall people tend to have children who also grow up to be tall.
People usually grow until they reach 18 years of age. Before then, a range of environmental factors can affect how tall they become.
This article covers the factors that affect a person’s height, some ways people can increase height during development, and whether or not adults can increase their height.
Babies and children grow continuously. This is due to changes in the growth plates in the long bones of their arms and legs.
As the growth plates make new bone, the long bones get longer, and the child gets taller.
People grow the fastest in the first 9 months of life, before being born. After birth, this slows down.
Once a child is 8 years old, they will grow at an average of 2.16 inches (in), or 5.5 centimeters (cm), per year.
That said, teenagers will have a “growth spurt” around the time of puberty. After this, the growth plates stop making new bone, and the person will stop growing. The hands and feet stop growing first, then the arms and legs. The last area to stop growing is the spine.
Due to typical aging processes, people begin to lose height gradually as they get older.
The following factors can affect how tall a person will become:
DNA is the main factor determining a person’s height.
Scientists have identified more than 700 different genes that determine height. Some of these genes affect the growth plates, and others affect the production of growth hormones.
Normal height ranges are different for people from different ethnic backgrounds. Again, this is determined by their DNA.
Some genetic conditions can also affect a person’s adult height, including Down syndrome and Marfan syndrome.
The body produces hormones that instruct the growth plates to make new bone. These include:
- Growth hormones: These are made in the pituitary gland and are the most important hormone for growth. Some health conditions can restrict the amount of growth hormones the body makes, and this can impact height. Children with a rare genetic condition called congenital growth hormone deficiency, for example, will grow at a much slower rate than other children.
- Thyroid hormones: The thyroid gland makes hormones that influence growth.
- Sex hormones: Testosterone and estrogen are very important for growth during puberty.
Males tend to be taller than females. Males may also continue growing for longer than females. On average, an adult male is 5.5 in (14 cm) taller than an adult female.
According to the Centers for Disease Control and Prevention (CDC), in the United States, the average male is 69 in (175.2 cm) tall, and the average female is 63.6 in (161.5 cm) tall.
Learn about what age girls stop growing and what age boys stop growing here.
People cannot control most of the factors that influence their height. This is because they are determined by DNA, which they cannot change.
However, some factors can increase or reduce growth during childhood and puberty. Growing children and teenagers can take some steps to maximize their adult height. These include:
Ensuring good nutrition
Nutrition plays a very important role in growth. Children without good nutrition may not be as tall as children with adequate nutrition.
Nutritionists recommend that children and young people eat a varied, balanced diet with plenty of fruit and vegetables. This will ensure that they get all the vitamins and minerals they need to thrive.
Protein and calcium are particularly important for bone health and growth. Some protein-rich foods include:
- nuts and seeds
Some calcium-rich foods include:
Ensuring good nutrition during pregnancy is also important for the bone health and growth of the fetus.
The World Health Organization (WHO) recommend that pregnant women consume a variety of foods, including “green and orange vegetables, meat, fish, beans, nuts, pasteurized dairy products, and fruit.”
Getting enough sleep
Sleep promotes growth and development in children and teenagers. During deep sleep, the body releases the hormones it needs to grow. Getting enough sleep may therefore allow optimal growth.
Getting regular exercise
Regular exercise is also important for normal physical development. Playing outside or taking part in sports, for example, can make bones healthier, denser, and stronger.
Once a person has been through puberty, the growth plates stop making new bone. They fuse together, and the person stops growing. This means that when a person reaches 18 years of age, they are not able to increase their height.
Practicing good posture and keeping the back and core muscles strong can allow a person to stand straighter and appear taller.
Learn more about growing factors that affect height as an adult here.
Height is largely determined by DNA. However, environmental factors such as nutrition and exercise can affect growth during development.
As children get older, they need good nutrition and plenty of exercise to help their bodies make the hormones they need to grow. Teenagers will experience a growth spurt during puberty. After that, their bones will stop growing, and they will not get any taller.
Good nutrition during pregnancy is also important for the future bone health and growth of the baby.