The true statement concerning thermoregulation in neonates is which of the following?

The true statement concerning thermoregulation in neonates is which of the following?

• A. Significant proportion of their heat loss is accounted for by their small surface area-to-weight ratio
• B. They compensate for hypothermia by shivering
• C. The principal method of heat production is metabolism of brown fat
• D. Heat loss through conduction can be reduced by humidification of inspired gases

Answer: (C)

In newborns, keeping warm relies mainly on non-shivering thermogenesis from brown adipose tissue. This tissue is rich in mitochondria and contains a protein that uncouples oxidative phosphorylation to heat instead of producing ATP. When a neonate is exposed to cold, the sympathetic nervous system stimulates brown fat to burn fats and release heat quickly, which is essential because newborns have limited ability to shiver and a high surface area-to-body mass that makes heat loss easy. That’s why this statement is the best: brown fat metabolism provides the principal heat production mechanism in neonates, helping to maintain core temperature in the face of significant environmental heat loss. In contrast, neonates rely less on muscle shivering, since their shivering response is immature. Their heat loss is not minimized by a small surface area-to-weight ratio (they actually have a large surface area relative to their mass, which favors heat loss). And while humidified inspired gases can reduce some respiratory heat loss, the major source of heat generation in this age group is brown fat metabolism, not conduction changes from humidification.

In newborns, keeping warm relies mainly on non-shivering thermogenesis from brown adipose tissue. This tissue is rich in mitochondria and contains a protein that uncouples oxidative phosphorylation to heat instead of producing ATP. When a neonate is exposed to cold, the sympathetic nervous system stimulates brown fat to burn fats and release heat quickly, which is essential because newborns have limited ability to shiver and a high surface area-to-body mass that makes heat loss easy.

That’s why this statement is the best: brown fat metabolism provides the principal heat production mechanism in neonates, helping to maintain core temperature in the face of significant environmental heat loss. In contrast, neonates rely less on muscle shivering, since their shivering response is immature. Their heat loss is not minimized by a small surface area-to-weight ratio (they actually have a large surface area relative to their mass, which favors heat loss). And while humidified inspired gases can reduce some respiratory heat loss, the major source of heat generation in this age group is brown fat metabolism, not conduction changes from humidification.