This study aimed to determine whether: (a) isometric handgrip (IHG) training lowers resting blood pressure (BP), (b) cardiovascular reactivity to a serial subtraction (SST), IHG (IHGT), and cold pressor (CPT) task predicts this hypotensive response, and (c) cardiovascular reactivity is attenuated posttraining. Resting BP and cardiovascular reactivity to a SST, IHGT, and CPT were measured in 24 hypertensives (51–74 years) before and after 10 weeks of IHG training (n = 12) or control (n = 12). IHG training lowered resting BP (Δ8/5 mmHg), whereby the decrease in systolic BP was correlated to pretraining systolic BP reactivity to the SST (r = −.85) and IHGT (r = −.79; all ps < .01), but not the CPT (r = .34; p > .01). Furthermore, following IHG training, systolic BP reactivity to the SST (Δ7 mmHg) and IHGT (Δ8 mmHg) was reduced (all ps < .01). The results offer promising implications for hypertensives and may provide a tool to identify IHG training responders.