If an individual has a respiratory exchange ratio (RER) of 0.97, which substrate are they primarily burning?

When evaluating the respiratory exchange ratio (RER), values can provide insight into the primary substrates being utilized for energy. An RER of approximately 0.97 suggests the predominant use of carbohydrates for energy production.

RER values range from 0.7 to 1.0, where lower values indicate a greater reliance on fats and higher values reflect a shift toward carbohydrate utilization. A value of 0.97 is close to 1.0, indicating that the individual is primarily metabolizing carbohydrates rather than fats or proteins.

In contrast, greater reliance on fats typically corresponds with an RER closer to 0.7, while protein oxidation usually results in an even lower RER. Alcohols, not typically measured through RER, would not fit into this metabolic context. Thus, the interpretation of an RER of 0.97 aligns with the notion that carbohydrates are the primary substrate being burned.