Improved medical care and nutrition has made American children less susceptible to life-threatening childhood diseases and accelerated their physical development, according to college textbooks "An Invitation to Health" and "Understanding Psychology." However, American children are also more likely to begin to develop adult diseases than children of earlier eras because they exercise less and eat more. They also are more likely to be psychologically unhealthy if their physical development is slow.
Expert Insight
Vaccines have reduced the number of cases of childhood illnesses such as chickenpox, German measles, measles, mumps and "other life-threatening illnesses" by more than 95 percent in the past 50 years, according to "An Invitation to Health."
The textbook reports that the American Academy of Pediatrics recommends that all children get three hepatitis B vaccines in their first 18 months as well as vaccines for chickenpox between 1 and 2 years of age; German measles, measles and mumps between 12 and 18 months; and diphtheria, tetanus and whooping cough between 15 and 24 months.
Height
The average child is 1 feet 8 inches tall at birth and 3 feet tall at age 3. Boys and girls are the same average height from birth to 11 1/2, when they're an average 4 feet 8 inches. Girls are taller from 11 1/2 to 14, when they're an average 5 feet 3 inches. Boys are taller after 14.
At 19, average males and females are 5 feet 9 inches and 5 feet 4 inches, respectively. Shorter boys are at greater risk of being psychologically unhealthy because they "tend to be ridiculed and seen as less attractive," according to "Understanding Psychology."
Sexual Maturity
Americans' age of sexual maturity "has been steadily decreasing" for the past 100 years, according to "Understanding Psychology."
Typically, boys begin ejaculating between the ages of 12 and 16, and girls begin menstruating between 11 1/2 and 13 3/4, while their breasts grow between 11 1/4 and 13 3/4.
Early bloomers are psychologically healthier and have better self-esteem because they are more popular, date more and do better in sports, the textbook reports.
Strength
Building muscles is also a sign of physical development, but about 25 percent of children don't exercise at all in school, according to the Centers of Disease Control and Prevention (CDC).
Building muscles improves children's health by reducing their risk of musculoskeletal injuries, strengthening their bones, improving their cardiovascular fitness and boosting their moods.
"Once children begin a program of exercise, they can lower their health risks dramatically within eight weeks," according to "An Invitation to Health."
Weight
American children in the 21st century are "more likely to be severely obese" and have "ominously high" blood pressure and cholesterol levels than 1980s children, according to "An Invitation to Health."
They also eat about 200 more calories daily, exercise less and are more likely to develop heart disease as adults if they maintain their habits.
The United States Department of Agriculture is alarmed about children's consumption of carbonated beverages, and its MyPyramid for Kids recommends six daily servings of grains, three of vegetables and two each of fruits, meat and milk.
References
- "An Invitation to Health"; Dianne Hales; 2003
- "Understanding Psychology"; Robert S. Feldman; 2002
- United States Department of Agriculture: MyPyramid For Kids
- Centers for Disease Control and Prevention: Measuring Children's Height and Weight
- Centers for Disease Control and Prevention: About BMI for Children and Teens
