Thermoregulation, or the ability to maintain a stable internal body temperature, is less efficient in children, especially infants. Newborns have a higher surface area-to-body weight ratio and less subcutaneous fat, making them more susceptible to temperature fluctuations. They rely on mechanisms like brown fat metabolism and increased metabolic rate to generate heat, but these are not as effective as the shivering and sweating responses seen in older children and adults.
