Question

A respiratory quotient (RQ) of 0.87 most likely suggests

1: primarily fat oxidation.
2: mixed substrate utilization.
3: primary carbohydrate oxidation.
4: primary protein oxidation.

Answer 1

A respiratory quotient (RQ) of 0.87 suggests that the body is using a mix of fats and carbohydrates for energy, indicating mixed substrate utilization.

Step-by-step explanation:

An respiratory quotient (RQ) of 0.87 suggests mixed substrate utilization. The RQ is a measure indicating which type of macronutrient your body is primarily using for energy; carbohydrates have an RQ close to 1.0, fats are about 0.7, and proteins are around 0.8. Since 0.87 is between the RQ values for fats and carbohydrates, this indicates that the person's metabolism is utilizing a mix of both fats and carbohydrates as sources of energy. This mixed utilization is common, as the body often uses multiple energy sources depending on activity level, diet, and overall metabolic demands.