What is the impact of thyroxine on the body's basal metabolic rate?

Thyroxine, a hormone produced by the thyroid gland, plays a crucial role in regulating the body's basal metabolic rate (BMR). By increasing the rate at which cells metabolize nutrients and produce energy, thyroxine enhances overall energy expenditure. This hormone stimulates the metabolism of carbohydrates, fats, and proteins, leading to an increase in the BMR. Higher levels of thyroxine result in more energy being used at rest, which subsequently leads to an increased caloric requirement. This hormone also influences the metabolic processes that generate heat, contributing to thermoregulation.

In contrast, other options such as decreasing energy expenditure or having no impact on metabolism do not accurately reflect the role of thyroxine. Additionally, while it is true that thyroid hormones can influence glucose metabolism, the primary function of thyroxine in this context relates directly to its effects on the basal metabolic rate rather than the regulation of blood sugar levels. Thus, understanding the central role of thyroxine in boosting metabolic activity underlines why the correct response regarding its influence on the body's basal metabolic rate is that it increases it.