From birth to adolescence there are significant shifts in normal vital signs, weight, and behavior. Recognizing that what is normal for an adult may be dangerously abnormal for an infant or child is essential. As a general rule, the older a patient is the slower the respiratory rate (RR) and heart rate (HR) will be, and the higher the systolic blood pressure.

Infant Physiology (birth to 12 months)

• HR: 140 to 160

• RR: 40 to 60 at birth, 30 - 60 after first few minutes of life

• Systolic BP: 70 mmHg at birth, gradually increases to 90 mmHg at one year

• Birth weight: generally from 3.0-3.5 kg (6.6-7.7 lbs) at birth

Pulmonary system - Airways are more easily obstructed as infants, who are primarily nose-breathers until 4 weeks old. Rapid respiratory rates lead to rapid heat and fluid loss.

Nervous system - Infants have strong, coordinated suck and gag reflexes, well-flexed extremities, and move extremities equally when the infant is stimulated.

Toddler Physiology (12 to 36 months)

• HR: 80 to 130

• RR: 20 to 30

• Systolic BP: 70 mmHg to 100 mmHg

• Temperature: 98.6 F to 99.6 F

Pre-School Age Physiology (3-5)

• HR: 80 to 120

• RR: 20 to 30

• Systolic BP: 80 mmHg to 110 mmHg

• Temperature: 98.6 F to 99.6 F

School-age Physiology (6 to 12)

• HR: 70 to 110

• RR: 20 to 30

• Systolic BP: 80 mmHg to 120 mmHg

• Temperature: 98.6 F to 99.6 F

Dental: Loss of primary "Baby" teeth and replacement with permanent teeth begins.

Adolescence (13 to 18) Physiology

• HR: 55 to 105

• RR: 12 to 20

• Systolic BP: 110 mmHg to 130 mmHg

• Temperature averages 98.6 degrees Fahrenheit.

Early Adulthood (20 to 40) Physiology

• HR: Average of 70; max normal of 100

• RR: 16 to 20

• Systolic BP: 120 mmHg average; max normal of 130 mmHg

• Temperature averages 98.6 degrees Fahrenheit.

Middle Adulthood (41 to 60)

Physiology (unchanged from early adulthood):

• HR: Average of 70; max normal of 100

• RR: 16 to 20

• Systolic BP: 120 mmHg average; max normal of 130 mmHg

• Temperature averages 98.6 degrees Fahrenheit.

Vision and hearing become less effective.

Cardiovascular health: becomes a significant concern.

Cancer is most prevalent in this age group. Weight control becomes more difficult as metabolism and activity levels lower. Menopause occurs in women in late forties to early fifties.

Psychological: the middle adulthood population generally approaches problems as challenges rather than threats.

• Empty nest syndrome, which is defined as a sadness or emotional distress that affects those whose children have left home, often begins at this age.
• Middle-aged adults are often burdened by financial commitments to elderly parents and young adult children or debt service which has accrued.

Late Adulthood Physiology (61 and older)

Normal vital signs are dependent on the patient’s physical conditioning and health status. For a healthy individual normal vital signs are largely unchanged from middle adulthood:

• HR: Average of 70; max normal of 100

• RR: 16 to 20

• Systolic BP: 120 mmHg average; max normal of 130 mmHg

• Temperature averages 98.6 degrees Fahrenheit.

Cardiovascular changes include: 

• decreases in circulation efficiency
• poor tolerance of tachycardia
• decrease in function blood volume

Respiratory System: affected by

• weakening of the chest wall,
• diminished gas exchange through the alveoli in the lungs, and
• diminished lung capacity.