Figure 1.

Response to exercise in our 4 primary measures of interest are displayed for all participants for the initial six minutes of exercise and peak values for those who met 85% of age predicted maximal heart rate and RER > =1.0. Filled shapes represent the nondemented group and open shapes represent the group with AD. Row A) displays oxygen consumption, which rose significantly faster during the initial 6 minutes of the test during 2-year follow-up testing (right graph). VO₂ peak was greater in the nondemented group at both timepoints. Row B) At follow-up testing, the AD group began testing with a lower heart rate but increased over the initial 6 minutes of testing to match the nondemented group (right graph), resulting in an interaction of Test Minute and Group. Peak heart rates were different between groups at baseline testing but not at follow-up. Row C) In both groups, VE rose at faster rate during the initial 6 minutes of exercise testing at follow-up compared to baseline, resulting in a significant interaction between Study Visit and Test Minute. Peak VE was greater in the nondemented group at baseline. Row D) Ventilatory equivalent for O₂ (left Y axis) and CO₂ (right Y axis) are presented together for ease of comparison. Interaction of Test Minute and Study Visit were evident for both measures, with steeper decline in VE/VCO₂ and earlier rebound in VE/VO2 at follow-up testing. Peak values were not different between groups.