Introduction: High-intensity interval training promotes significant reductions in blood pressure among older adults with hypertension. However, there is a lack of evidence regarding its application in low-cost models that are feasible and scalable in everyday settings. Purpose: This pilot study was conducted to examine the feasibility and preliminary effects of an outdoor high-intensity interval training program guided by perceived exertion on 24-hour ambulatory blood pressure in older adults with hypertension, thereby providing evidence to guide the design and implementation of a subsequent, larger-scale clinical trial. Methods: Thirty-one participants (66±4 years; hypertension duration: 14±9 years) were randomized to a six-week intervention: Exercise group (n=18) or control (n=13). The exercise group performed three weekly outdoor sessions, progressing from four to eight 1-minute bouts at a perceived exertion of 7–8, interspersed with active recovery at 3–4. Heart rate and affective response (Feeling Scale) were monitored. The control group attended weekly health education sessions. Results: Feasibility was assessed via consent (18.6%), retention (83.3%), adherence (89%), and adverse events (11.1% reported musculoskeletal issues). Participants trained at >75% Heart rate reserve and >85%, maximum heart rate with positive affective ratings. The HIIT group showed reductions in 24-hour systolic (-3 mmHg), diastolic (-2 mmHg), and nighttime systolic BP (-5 mmHg) (p<0.05). Nighttime diastolic BP (-3 mmHg) and augmentation index (-5.6%) also decreased, though not significantly. Conclusion: In conclusion, an outdoor high-intensity interval training program based on perceived exertion is feasible for older adults with hypertension and may lead to clinically meaningful reductions in 24-hour ABP.