Japanese Interval Walking: The Research Behind Interval Walking Training

Unlike continuous walking at the same pace, IWT alternates periods of brisk walking with periods of slower walking. The classic research protocol uses 3 minutes of brisk walking followed by 3 minutes of slow walking, repeated for at least five sets.

The method was developed to make changes in walking intensity a practical part of regular exercise. Research has investigated its effects on physical fitness, muscle strength, blood pressure, metabolic health, and other measures of health in primarily middle-aged and older adults.

Japanese Interval Walking is a reader-friendly name for this research-based approach. The formal term used in the scientific literature is Interval Walking Training, or IWT.

Interval Walking Training was developed and studied at Shinshu University in Japan. In the classic protocol, participants alternate 3 minutes of high-intensity walking with 3 minutes of low-intensity walking. The high-intensity periods are intended to be substantially more demanding than ordinary walking, while the low-intensity periods provide recovery before the next brisk interval.

In the original research protocol, brisk walking was prescribed at approximately 70% or more of an individual's peak aerobic capacity, while slow walking was performed at approximately 40%. This means that the target intensity is relative to the individual rather than a single walking speed that applies to everyone.

One of the early large studies was a randomized controlled trial published in 2007. Nemoto and colleagues studied 246 adults with an average age of about 63 years and compared Interval Walking Training with moderate continuous walking and a non-exercise control group. Participants assigned to IWT performed repeated 3-minute low- and high-intensity walking intervals for at least five sets, at least four days per week, over five months.

The IWT group showed improvements in several measures of physical fitness and muscle strength. The study reported increases in knee extension strength, knee flexion strength, and peak aerobic capacity, and also found a greater reduction in resting systolic blood pressure than in the moderate continuous walking group.

A larger study published in 2019 examined 679 middle-aged and older adults who participated in five months of IWT. The researchers estimated that peak oxygen uptake increased by about 14%, while a composite score representing lifestyle-related disease risk decreased by about 17%. The study also found that the relationship between weekly fast-walking time and improvements tended to level off after approximately 50 minutes per week.

The 2019 finding does not mean that 50 minutes is a universal optimal amount of brisk walking. It describes a pattern observed in that study. Individual responses, exercise capacity, health status, and adherence can all affect the outcome.

Research on IWT has continued beyond these early studies. A 2024 review concluded that Interval Walking Training has been associated with improvements in physical fitness and muscle strength and has shown promising effects on several measures related to lifestyle-related diseases and glycemic control. At the same time, the review noted the need for additional research, particularly on long-term effectiveness and implementation in real-world populations.

More recent research has examined specific outcomes in different populations. For example, a 2024 study of postmenopausal women found increases in bone mineral density after five months of IWT, with particularly notable changes among participants who started with lower bone mineral density. Findings such as these are interesting, but they should not be interpreted as proof that IWT prevents osteoporosis or produces the same result in everyone.

Overall, the research suggests that structured changes in walking intensity can provide meaningful training stimuli without requiring continuous high-intensity exercise. However, IWT is not a treatment for a specific disease, and research findings from particular study populations should not be treated as guarantees for individual results.