1. Superior Cardiovascular Fitness A landmark program from Fukuoka University found that four months of IWT boosted VO₂ max by ~11 % in men and ~7 % in women aged 50‑70—numbers comparable to beginner running plans without the joint stress. 2. Clinically Meaningful Blood‑Pressure Drops A 2023 randomized trial of community‑dwelling Japanese adults (average age 71) reported an average 9 mmHg reduction in systolic blood pressure after home‑based interval walking, far outpacing the non‑exercise control group. 3. More Fat Burn in Less Time Laboratory studies show that alternating fast and slow bouts during walking doubles fat oxidation compared with steady‑pace walking at the same total duration. The interval pattern also raises post‑exercise calorie burn for several hours. 4. Stronger Muscles, Especially in the Legs In the original high‑intensity IWT cohort, participants improved thigh‑muscle strength and endurance markedly more than peers doing continuous moderate walking, helping counter age‑related sarcopenia. 5. Sharper Brain & Better Mood A series of follow‑up trials link Japanese interval walking with improved executive function, working memory, and mood elevation in older adults—likely thanks to increased cerebral blood flow and BDNF release during the brisk phases. 6. Joint‑Friendly HIIT Alternative Because the fast segments are still walking, ground‑reaction forces remain far lower than jogging. Physicians interviewed by The Washington Post highlight IWT as a safe entry point for people with knee or lower‑back concerns who still want HIIT‑level cardio gains. 7. Posture, Balance & Core Stability Switching to Namba walking—moving the same arm and leg together—reduces torso rotation, which can lessen shear stress on the spine and train proprioception. Biomechanics papers note smoother pelvic tracking and a potential reduction in knee‑adduction moments. 8. Sustainable, Time‑Efficient & Equipment‑Free A single 30‑minute session—performed four days per week—meets the World Health Organization’s vigorous‑activity guideline. Participants report higher adherence than with traditional step‑count goals because the clear on/off rhythm feels achievable and engaging.1.