How do newborns primarily regulate their body temperature?

• A. By sweating to cool down
• B. By increasing metabolic activity
• C. By increasing fluid intake
• D. By reducing physical activity

Answer: (B)

Newborns primarily regulate their body temperature by increasing metabolic activity. This is particularly significant because, unlike adults who utilize mechanisms such as sweating to cool down, newborns do not have the same level of sweat gland function. Instead, they rely on thermogenesis, which is the process of heat production in the body, to maintain their body temperature. They have a higher basal metabolic rate and generate heat through the breakdown of brown adipose tissue. This specialized fat, known as brown fat, is highly vascularized and plays a critical role in non-shivering thermogenesis, helping to keep newborns warm.

This mechanism is crucial for newborns, who may not yet be able to shiver as a way to produce heat and are vulnerable to hypothermia, especially in the first few days of life. The other options, like sweating for cooling, increasing fluid intake, or reducing physical activity, are less applicable in newborns, particularly since they do not sweat efficiently or drink water in the way older children and adults do. Instead, their primary reliance on metabolic activity underscores the importance of maintaining a warm environment to support their natural thermoregulatory processes.