Table 3. Measurements during maximal exercise (VO2max) testing (n = 7). Values are Mean ± SD.
Variables LCHF HCLF P Value
PreDay 1 PostDay 39 PreDay 1 PostDay 39 Condition Time Interaction
Maximal Data
Time to Exhaustion (sec) 844.3 ± 87.3 818.6 ± 114.5 775.7 ± 107.4 801.4 ± 74.9 0.251 1.000 0.206
VO2max (ml/kg/min) 61.6 ± 3.1 62.9 ± 6.9 60.6 ± 8.4 62.5 ± 6.0 0.435 0.027 0.854
VO2max (L/min) 4.2 ± 0.2 4.3 ± 0.6 4.2 ± 0.6 4.3 ± 0.4 0.476 0.088 0.773
VCO2max (L/min) 4.6 ± 0.3 4.4 ± 0.7 4.7 ± 0.7 4.9 ± 0.5 0.022 0.812 0.316
HRmax (b/min) 180.9 ± 11.4 181.1 ± 10.0 178.6 ± 15.0 179.2 ± 10.5 0.195 0.757 0.881
VEmax (L/min) 115.3 ± 26.1 121.3 ± 23.5 119.0 ± 17.1 125.2 ± 20.9 0.514 0.086 0.987
RRmax (bpm) 47 ± 10 47 ± 8 48 ± 8 47 ± 9 0.774 0.920 0.613
Peak RER 1.09 ± 0.09 1.03 ± 0.08 1.13 ± 0.07 1.14 ± 0.05 0.004 0.176 0.072
Peak Carbohydrate Oxidation (g/min) 7.2 ± 1.5 6.2 ± 1.6 8.0 ± 1.5 8.5 ± 1.2 0.009 0.522 0.148
Peak Fat Oxidation (g/min) 1.01 ± 0.21 1.26 ± 0.20 0.67 ± 0.14 0.66 ± 0.23 0.001 0.093 0.072
Average Data
Mean VO2 (ml/kg/min) 44.8 ± 2.5 45.2 ± 4.0 43.7 ± 4.4 44.3 ± 3.1 0.134 0.588 0.906
Mean VO2 (L/min) 3.1 ± 0.2 3.1 ± 0.3 3.0 ± 0.3 3.0 ± 0.2 0.283 0.738 0.523
Mean VCO2 (L/min) 2.8 ± 0.3 2.6 ± 0.3 2.9 ± 0.4 3.0 ± 0.2 0.015 0.465 0.149
Mean VE (L/min) 70.7 ± 19.0 71.9 ± 15.9 72.9 ± 13.0 77.4 ± 14.5 0.216 0.053 0.588
Mean RR (bpm) 34 ± 7 34 ± 6 36 ± 8 36 ± 8 0.064 0.850 0.845
Mean RER 0.9 ± 0.06 0.83 ± 0.05 0.95 ± 0.04 0.96 ± 0.03 0.001 0.042 0.050
Mean Carbohydrate Oxidation (g/min) 3.0 ± 0.9 2.1 ± 0.8 3.6 ± 0.8 3.7 ± 0.4 0.001 0.106 0.075
Mean Fat Oxidation (g/min) 0.43 ± 0.34 0.74 ± 0.25 0.16 ± 0.22 0.13 ± 0.18 0.001 0.032 0.047
LCHF, low carbohydrate high fat; HCLF, high carbohydrate low fat; VO2 = oxygen consumption; VCO2 = carbon dioxide production; HR = heart rate; RER = Respiratory exchange ratio; VE = ventilation; RR = Respiratory Rate