How brisk should the brisk intervals be?

In the Shinshu University studies, brisk meant at least 70% of each walker's measured peak aerobic capacity for walking, and easy about 40%. Without a lab test, a practical approximation is a pace that feels somewhat hard — breathing clearly harder, able to speak only in short phrases — followed by a relaxed pace that lets your breathing settle.

Japanese walking · Interval walking training (IWT)

The Japanese walking method, explained

Q: What is Japanese walking?

Japanese walking, also called interval walking training (IWT), alternates 3 minutes of brisk walking with 3 minutes of easy walking, repeated at least five times — 30 minutes a session, at least four days a week. It was developed by Hiroshi Nose and Shizue Masuki at Shinshu University in Matsumoto, Japan, and first published in Mayo Clinic Proceedings in 2007.

Q: Does a Japanese walking app keep working with the screen locked?

Only if it is built to. iOS suspends most apps shortly after the screen locks, so a countdown that runs only on screen can no longer speak to you. An app keeps cueing while the iPhone is locked in one of three ways: it keeps audio playing in the background and speaks its own cues; it schedules notifications in advance, which fire on time but follow your silent switch and Focus settings; or, on Apple Watch, it runs a workout session. Strolla uses background audio on iPhone and a workout session on Apple Watch.

Japanese walking — also called interval walking training (IWT) — alternates 3 minutes of brisk walking with 3 minutes of easy walking, repeated at least five times: 30 minutes a session, at least four days a week. In the research, brisk meant at least 70% of each walker's peak aerobic capacity for walking, and easy about 40%. The method was developed by Hiroshi Nose and Shizue Masuki at Shinshu University Graduate School of Medicine in Matsumoto, Japan, and first published in Mayo Clinic Proceedings in 2007.

Last verified against the primary sources: October 2, 2026 · Sources

The protocol at a glance

Element	As used in the Shinshu University studies
Brisk interval	3 minutes at 70% or more of your peak aerobic capacity for walking
Easy interval	3 minutes at about 40% of peak aerobic capacity
Sets per session	5 or more (5 sets = 30 minutes, 15 of them brisk)
Sessions per week	4 or more days
Study length	4 to 5 months

In the 2007 study, each set was described as 3 easy minutes followed by 3 brisk minutes; later papers describe the same pair as fast and slow walking.

Why the brisk minutes matter most

A 2019 analysis of 679 people who completed five months of interval walking found that their improvements grew with the time they spent walking fast each week — up to about 50 minutes of fast walking per week, after which the gains levelled off. Time spent walking slowly, and total walking time, were not positively correlated with the improvements. Five sets of 3 brisk minutes, four days a week, is 60 brisk minutes: just past that point.

What the studies measured

These are results for groups of study participants — mostly middle-aged and older adults in Japan. They describe what the researchers measured, not what any individual, or any app, will achieve.

2007 · the original study

246 adults (60 men, 186 women; mean age 63) were randomly assigned to no training, to moderate continuous walking (about 50% of peak capacity, 8,000+ steps a day, 4+ days a week), or to interval walking, for five months. In the interval walking group, knee extension strength rose by 13%, knee flexion strength by 17%, and peak aerobic capacity by 8% (cycling) and 9% (walking) — all significantly more than in the continuous walking group. The drop in resting systolic blood pressure was also larger with interval walking. Nemoto et al., Mayo Clinic Proceedings, 2007.

2011 · a larger group of 666

826 adults (around age 65) did four months of interval walking; 666 completed every measurement before and after. Fitness at the start, and how much it changed with training, were closely linked with markers of lifestyle-related diseases such as blood pressure, blood glucose and body-fat measures. Morikawa et al., British Journal of Sports Medicine, 2011.

2019 · 679 walkers, and the dose

679 adults (mean age 65) completed five months of interval walking. Estimated peak aerobic capacity rose by 14% and a composite lifestyle-related disease score fell by 17% on average, and the gains tracked weekly fast-walking time up to about 50 minutes (see above). Masuki, Morikawa & Nose, Mayo Clinic Proceedings, 2019.

2024 · a review of the evidence

A review co-authored by the method's developers concluded that interval walking is efficacious in improving physical fitness and muscle strength and in reducing factors associated with lifestyle-related diseases — and that staying with it long-term remains a challenge, especially for people with chronic disease or overweight, with long-term real-world studies still needed. Karstoft et al., Applied Physiology, Nutrition, and Metabolism, 2024.

How brisk is brisk?

In the studies, each participant's intensity was set from their own measured peak aerobic capacity, and in the 2007 study the walking was monitored with an accelerometer. Most people do not have a lab test, so they go by feel. A practical approximation — not the studies' method — is:

Brisk: somewhat hard. You are breathing clearly harder and could speak only in short phrases, not hold a comfortable conversation.
Easy: relaxed. Your breathing settles and you could talk normally.

Brisk is personal: a pace that is hard for one walker is easy for another, and yours will change as you get fitter.

Does a Japanese walking app keep working with the screen locked?

Only if it is built to. On iPhone, iOS suspends most apps shortly after the screen locks or they leave the screen. A countdown that runs only on the screen stops being able to speak to you as soon as the phone goes into your pocket — which is exactly when you need it during a 30-minute walk. An app can keep cueing a locked iPhone in one of three ways:

Background audio. The app keeps audio playing for the length of the walk — a silent track between cues is enough — which iOS allows for apps that play audio, and speaks each cue itself at the boundary. Done well, it can let your music keep playing and dip it only while a cue is spoken.
Scheduled notifications. The app schedules an alert for every boundary before you lock the phone. The alerts arrive on time, but they follow your ring/silent switch and Focus settings, so a cue can arrive as a silent vibration or a banner you never see.
An Apple Watch workout session. A watch app that runs a workout keeps running for the length of the workout and can tap your wrist at each boundary, whatever your iPhone is doing.

Strolla uses the first on iPhone and the third on Apple Watch. Its spoken cues are generated on the device, your music keeps playing and dips only for the moment a cue is spoken, and podcasts pause briefly for the cue. No approach is immune to everything: a phone call, for example, takes over the audio; Strolla resumes its cues when the call ends.

How to check any app yourself: start a walk, lock the phone, put it in your pocket, and wait for the next interval boundary — once with your music playing, and once with the silent switch on.

Common questions

Is "Japanese walking" the same as interval walking training?

Yes. "Japanese walking" is the popular name for the interval walking training (IWT) protocol developed at Shinshu University.

How long is a Japanese walking session?

30 minutes: five sets of 3 minutes brisk and 3 minutes easy. The studies asked for at least five sets a day, on at least four days a week.

Do I need an Apple Watch or a heart-rate monitor?

No. The protocol needs only a way to know when each 3-minute interval ends; most walkers judge the pace by feel (see How brisk is brisk?). A watch adds wrist taps and heart-rate readings, but it is optional.

Is it safe for me?

Check with your doctor before starting a new exercise program, especially if you have a heart, lung or joint condition, are pregnant, take medication that affects your heart rate or blood pressure, or have not exercised in a while. Walk at an effort that is right for you, and stop if you feel chest pain, dizziness or unusual shortness of breath.

Walking it with Strolla

Strolla is an iPhone and Apple Watch coach for this protocol. The standard walk is 3 minutes brisk and 3 minutes easy, five times, with a calm spoken cue at every boundary, so you can lock the phone, keep your music on and just walk. It counts your brisk minutes, walk by walk, and, with your permission, saves each walk to Apple Health. There is no account, and Strolla collects no data (privacy policy).

Sources

Nemoto K, Gen-no H, Masuki S, Okazaki K, Nose H. Effects of high-intensity interval walking training on physical fitness and blood pressure in middle-aged and older people. Mayo Clinic Proceedings. 2007;82(7):803–811. doi:10.4065/82.7.803
Morikawa M, Okazaki K, Masuki S, Kamijo Y, Yamazaki T, Gen-no H, Nose H. Physical fitness and indices of lifestyle-related diseases before and after interval walking training in middle-aged and older males and females. British Journal of Sports Medicine. 2011;45(3):216–224. doi:10.1136/bjsm.2009.064816
Masuki S, Morikawa M, Nose H. High-intensity walking time is a key determinant to increase physical fitness and improve health outcomes after interval walking training in middle-aged and older people. Mayo Clinic Proceedings. 2019;94(12):2415–2426. doi:10.1016/j.mayocp.2019.04.039
Karstoft K, Thorsen IK, Nielsen JS, Solomon TPJ, Masuki S, Nose H, Ried-Larsen M. Health benefits of interval walking training. Applied Physiology, Nutrition, and Metabolism. 2024;49(7):1002–1007. doi:10.1139/apnm-2023-0595
Overview: Interval walking training, Wikipedia.

This page is general information, not medical advice. Strolla is a walking coach, not a medical device. Strolla is an independent app and is not affiliated with or endorsed by Shinshu University or any of the researchers cited above.