Here is a graph of the data from my VO2max testing. RER is normalized (x100 to fit on the same scale)
My VO2max value didn’t quite flatten out which indicates I was not at the end of my VO2max range. But I was pretty close to the end.
0.7 is fat burning. 1.0 is carb burning. 0.85 is mixed fuel (half carb and half fat). Lowest was 0.59 which is heavy fat burning (and probably high levels of gluconeogenesis).
[2018-06-20: Here’s an explanation from the HyperLipid BLOG of how RER can go below 0.70 – On Stephen Phinney and an RQ of 0.62. See also this [Protein catabolism should generate an RQ of around 0.8].
Heart Rate Values
My max heart rate is 163 (220-57(age)). My peak value during the VO2max test was 173. My fat burning range was 84 to 117. My RER value was 0.7 or less through this whole range. My minimum RER of 0.59 was at a heart rate of 99. This indicates to me that if I work at around 100 bpm I am at maximum fat burning efficiency.