Adolescence: physical changes
Adolescence is one of the most rapid phases of human development.12 Although the order of many of the changes appears to be universal, their timing and the speed of change vary among and even within individuals. Both the characteristics of an individual (e.g. sex) and external factors (e.g. inadequate nutrition, an abusive environment) influence these changes.13-15
Many biological changes take place during the adolescent years. Most obvious are the physical changes, for example, increases in height, acquisition of muscle mass, the distribution of body fat and the development of secondary sexual characteristics.
Underlying these physical changes is a wide spectrum of endocrine changes (gonadarche and andrenarche), including hormones that affect gonadal maturation and the production of gonadal sex steroids. The growth spurt during early and mid-adolescence is regulated by the complex, inter-related production of a number of hormones.16 It takes place later and over a longer period in boys than girls. Hormonal changes, such as the regulation of oxytocin and vasopressin, also may affect how adolescents interact with others.17Tanner stages
Internal and external influences at work. All of these biological changes can be affected by factors internal to the adolescent, such as chronic illness and under-nutrition, and by external factors, such as stress within the family.
Similar factors may affect girls and boys differently. For example, high body mass index (BMI) may be associated with earlier puberty in girls but delayed puberty in boys.18 19 Similarly, early puberty may affect obesity in adolescent girls and boys differently.20
Health is the basis for everything. If you want to study or work, you need to be in good physical and mental health.
female, 15-17, South Africa
Adolescents on the meaning of health: To have the ability to do things well, without any sort of discomfort or pain. To ensure a comfortable future, without any complications like diabetes or any sort of cardiac disease, etc., caused by what was done in the past.
Gender not specified, 18–19, Mexico
Your health is not only your future but also the future of those around you. If I were to die at a young age, I would be unable to contribute to the economy or the population. An individual contracting a disease increases the risk of other individuals within that community contracting it. Therefore, it is important to keep healthy to ensure my safety and the safety of others.
female, 15-17, Saudi Arabia
If you feel well, you produce, you contribute, you are happy and you create a positive social environment.
female, 18-19, Mexico
Health is relative, based on the way you observe it. You can have a healthy body but an aching soul. I think it sums up to a balance of forces that make your body and mind work together to be able to experience freedom and with that, to create goals.
male, 15-17, Mexico
The proper functioning of one person is crucial for the society because our problems affect our behaviour, which will sooner or later affect the whole society.
trans, 12-14, Argentina
Health is life. Being in good health allows you to really throw yourself into life.
female, 15-17, France
It is important because I want to live a long life, and I don't want to be restricted by any illness that would be the result of being unhealthy. I want to be a role model to children that I may have because I know how important it is to have someone that you can look up to and to motivate you to be healthy and to exercise.
female, 15-17, United Kingdom
Health is important to me because being in a state of complete health means being able to function at my full potential, and hence being able to perform at my best and contribute as much as I can to the activities I am involved in.
female, 15-17, Switzerland