The effect of an aerobic training program on cadiovascular reactivity to the cold pressor test

Forty-two college age students enrolled in a Personal Health class at Virginia Tech with exercise capacity ≤ 16 METs and diastolic blood pressure (DBP) reactivity to the cold pressor test ≥ 5 mm Hg were randomly assigned to either an intervention group or a control group. The intervention group was asked to participate in an aerobic exercise session 4 d/wk for 8 weeks, consisting of walking/jogging for 30 minutes at or near their target heart rate range (75-85% of heart rate reserve).

There were no significant differences between groups in terms of initial fitness levels and any blood pressure (BP) and heart rate (HR) baseline or reactivity measures. After the training program, the average increase in exercise capacity for the intervention group was significantly greater (M=1.7, SEM=0.3) than the control group (M=0.6, SEM=0.2, p≤.05). No significant differences were observed in BP and HR baselines at the post-intervention cold pressor test. Controlling for pre-intervention reactivity levels by using ANGOVAs, the post-intervention reactivity scores were found to be unaffected by group assignment. HR recovery to the cold pressor test (in the first minute) was significantly faster in the intervention group at post-intervention (p<.05).

No relationship was demonstrated between reported compliance to exercise and changes in fitness (i.e., submaximal predicted METs). Thus, an analysis of 8 subjects known to comply w1th the exercise protocol (i.e., 26 sessions attended, 87% compliance) compared to the 34 remaining subjects was completed. A significant group effect was revealed in the modification of DBP reactivity (p<.05) but not SBP or HR reactivity. Based upon the original experimental analysis, results from the aerobic training study do not support the hypothesis that aerobic fitness moderates CVR to environmental stress. However, the re-analysis comparing known exercise compi1ers to all others did support the hypothesis that aerobic fitness reduces DBP reactivity to the cold pressor test. These findings suggest a potential role of aerobic fitness in modifying CVR to environmental stress.