Question

What does it mean when RER is greater than 1?

Answer 1

Respiratory exchange ratio (RER):

1. It is the relationship between the amount of CO₂ generated by the body and the amount of O₂ consumed by the body.
2. When measured at the cellular level, this parameter is known as the respiratory quotient (RQ).
3. In most cases, measurements of the breathed air are utilised to determine it.
4. The RER may be used to determine total energy expenditure and the contribution of lipids and carbohydrates to energy generation.

When RER is greater than 1:

1. The RER value close to 0.7 suggests that fat is the predominant fuel source, a value of 1.0 indicates that carbohydrate is the primary fuel source, and a value between 0.7 and 1.0 indicates that both fat and carbohydrate are utilised.
2. A varied diet is related with an RER of around 0.8.
3. During strenuous activity, the RER may approach 1.0.
4. A value larger than 1.0 is due to the aforementioned bicarbonate buffering effects rather than substrate metabolism.