Educational information, not medical advice. Drafted with AI from the sources cited and reviewed before publishing. How we work.
A research team at Shinshu University in Japan ran a series of trials starting in 2004, testing whether alternating fast and slow walking outperforms a steady moderate pace for middle-aged and older adults. The protocol: 3 minutes at a brisk effort, then 3 minutes at an easy pace, repeated at least 5 times per session. The original papers enrolled adults aged 60 to 65 and measured things worth measuring: aerobic fitness, leg muscle strength, and blood pressure. Below is what the results show, and where the online claims about weight loss and belly fat go past the evidence.
Key Takeaways
- Three Shinshu University trials enrolled adults aged 60-65 and used the 3-min fast / 3-min slow protocol, prescribed 5 sets per session, 4 or more days per week
- In a randomized trial (Nemoto 2007, n=246, mean age 63), interval walkers gained 13-17% more knee strength and 8-9% more aerobic capacity over 5 months, all greater than a moderate walking control group
- Blood pressure reduction was greater in the interval walking group than the moderate walking group
- A 4-month pre-post study (Morikawa 2011, n=666) found decreases in BMI, body fat, blood pressure, and blood glucose, but had no sedentary control group for body composition
- A 22-month adherence study (Masuki 2015, n=696) found 70% average adherence correlated with a 12% increase in VO2peak and a 13% reduction in a lifestyle-related disease score
- The original trials did not test weight loss; a separate Danish trial in people with type 2 diabetes found fat mass decreased with interval walking versus continuous walking
In this article: 3-and-3 timer · Where it came from · What the trials found · What they didn't test · How to do it · vs 10,000 steps · FAQ
3-and-3 Interval Walking Timer
Start the session here. The timer runs 3 minutes at easy pace, then 3 minutes at brisk pace, and repeats for as many rounds as you choose. Five rounds equals 30 minutes, matching the minimum the Shinshu trials used. Audio tones signal each phase change, so you can put your phone in a pocket after pressing Start.
The Shinshu studies set the slow phase at approximately 40% of each participant's peak aerobic walking capacity and the fast phase above 70%. Without a VO2peak test, go by effort: during the slow phase you should be able to speak full sentences without pausing to breathe; during the fast phase you can manage a few words but not a full conversation. The studies monitored participants with accelerometers. The timer approximates that structure by duration; effort is yours to calibrate.
Start, then put your phone in your pocket. Audio tones signal each phase change. 5 rounds = 30 minutes.
Uses the 3-and-3 interval protocol from the Shinshu University IWT studies. For educational use only. Not medical advice. Consult your doctor before starting any new exercise program.
Where the Method Came From
Shinshu University's Department of Sports Medical Sciences in Matsumoto, Japan produced three trials on interval walking training (IWT) between 2004 and 2015. The research group included Kiyoji Nemoto, Hirohito Gen-no, Shizue Masuki, and Hiroshi Nose.
The first trial (Nemoto et al., Mayo Clinic Proceedings, 2007) was a randomized controlled trial. Two hundred forty-six adults (60 men and 186 women, mean age 63 ± 6 years) were assigned to no training, moderate continuous walking, or high-intensity interval walking for 5 months. Participants were tested before and after on leg muscle strength and aerobic capacity.
A second larger study (Morikawa et al., British Journal of Sports Medicine, 2011) followed 826 adults (246 men and 580 women, mean age approximately 65) through a 4-month IWT program. The team analyzed the 666 who completed all measurements.
A third study (Masuki et al., Journal of Applied Physiology, 2015) followed 696 adults (mean age 65 ± 7 years) for 22 months, examining what predicted whether people stayed with the program and what outcomes tracked with adherence. All three studies enrolled middle-aged and older Japanese adults.
What the Original Trials Found
In the Nemoto 2007 randomized controlled trial, the interval walking group gained 13% more isometric knee extension strength and 17% more knee flexion strength over 5 months. Peak aerobic capacity for cycling improved by 8% and for walking by 9%. All four increases were significantly greater than the improvements in the moderate continuous walking group (all P<.01). Resting systolic blood pressure fell more in the interval walking group than in the moderate walking group (P=.01).
In the Morikawa 2011 study, all 666 participants who completed measurements showed increases in aerobic capacity and thigh muscle strength alongside decreases in body weight, BMI, percent body fat, blood pressure, and blood glucose (all P<.05). This was a pre-post comparison: everyone did interval walking, and there was no sedentary control group. The results show what participants measured before and after the program, not a direct comparison against doing nothing.
Across both studies, participants who started with the lowest fitness levels showed the largest improvements. In Morikawa's analysis, those in the lowest aerobic capacity group at baseline gained the most on all outcomes.
The 22-month Masuki adherence study found average adherence of 70% across 696 participants. Higher adherence correlated with a 12% increase in VO2peak and a 13% reduction in a composite lifestyle-related disease score (both R²=0.94, P=0.006). This is correlation data: people who completed more sessions also showed greater improvements, but the design does not establish cause.
What the Trials Did Not Test
The Nemoto 2007 RCT measured leg strength, aerobic capacity, and blood pressure. It did not measure body weight or body fat. The Morikawa 2011 study observed decreases in BMI and body fat alongside fitness gains, but had no sedentary control group for those measures. Without a non-walking comparison group, the study cannot establish whether those changes came from the IWT program specifically, from seasonal factors, from dietary changes, or from other shifts in behavior common in a wellness-focused trial population.
Weight loss and belly fat reduction were not outcomes the original Shinshu trials were designed to test.
A separate Danish trial (Karstoft et al., Diabetes Care, 2013) tested interval walking versus continuous walking and a control group in 32 adults with type 2 diabetes over 4 months. The interval walking group's VO2max increased by 16.1% (±3.7%), and fat mass and visceral fat decreased only in the interval walking group. Those are meaningful findings. The participants all had type 2 diabetes, which affects metabolism, body composition, and how the body responds to exercise. Applying those results to healthy men goes beyond what the study supports.
The weight loss and belly fat claims that circulate online cite no study that enrolled healthy adults and measured fat mass against a proper control group. Treat them as unverified.
How to Do It Without a Lab
The trials used accelerometers and VO2peak testing to set and verify intensity. Three practical anchors replace that equipment.
Easy phase effort: Walk at a pace where you can say a full sentence aloud without pausing to breathe. Your breathing rate is up, but you could hold a conversation. This corresponds to roughly 40% of peak aerobic capacity, the level the studies prescribed.
Brisk phase effort: Walk at a pace where speaking becomes harder. You can say a few words, but a full sentence requires a breath break. This corresponds to 70% of peak aerobic capacity and above. On flat ground, most men reach this at somewhere between 3.5 and 4.5 mph, though the right speed varies by fitness level and the studies did not prescribe a fixed speed.
On a treadmill: Start at your easy pace for 3 minutes, then increase speed until the effort matches the brisk description above and hold for 3 minutes. Transition back down. A difference of 0.5 to 1.0 mph between phases is a starting point; adjust based on how the effort feels against the descriptions above.
Outdoors: Use a flat route. A phone timer, a smartwatch, or the on-page timer above handles the intervals. Hilly terrain shifts intensity, so a flat path keeps the effort in your control, at least until you know how hard each phase is.
The studies prescribed at least 4 days per week, with at least 5 sets per session. That is the dose the trials used. Whether fewer days or rounds produce the same outcomes is not known from this research.
Japanese Walking vs 10,000 Steps vs Running
No head-to-head trial compares the Japanese walking method against 10,000 steps or running on the same outcomes in the same population. The table below compares characteristics based on what the respective research measures.
| Feature | Japanese walking (5 rounds) | 10,000 steps (walking) | Running (30 min) |
|---|---|---|---|
| Session time | 30 minutes | ~90 min at average pace | 30 minutes |
| Intensity | Alternates easy and vigorous | Mostly moderate | Moderate to vigorous |
| Impact per step | Low (walking throughout) | Low (walking throughout) | Higher (running impact) |
| Leg strength evidence | +13-17% knee strength in 5-month RCT (Nemoto 2007) | Not a primary outcome in step-count studies | Varies by training type |
| Aerobic fitness evidence | +8-9% aerobic capacity in Nemoto RCT; +16% in diabetics (Karstoft 2013) | Higher step counts associated with lower mortality (JACC 2023) | Well-documented aerobic gains |
| Evidence base for men 40-65 | Three trials, Japanese adults 60-65 | Large observational studies | Large observational and RCT data |
For step count evidence and the 7,000-step mortality threshold, see the daily steps mortality calculator. For the cardiovascular case for sustained low-intensity effort, see the zone 2 cardio guide. For rucking as a calorie-boosted walking option, see rucking benefits with calorie calculator. If knee issues are the constraint, see low-impact exercises for men with bad knees.
FAQ
Is the Japanese walking method the same as HIIT?
No. HIIT intervals last 20 to 90 seconds at near-maximal effort. The Japanese walking protocol uses 3-minute phases at above 70% aerobic capacity during the brisk phase, which is vigorous but not maximal. The stress and recovery demands differ from HIIT, and the research bases do not overlap.
How many days a week should I do it?
The Shinshu trials prescribed at least 4 days per week. The Masuki 2015 adherence study found that participants averaging 70% of that target correlated with the best fitness and disease score outcomes. Whether 3 days produces the same result has not been tested in this protocol.
Can I do it with bad knees?
The protocol uses walking throughout, which is lower-impact than running. The Shinshu trials enrolled adults in their 60s without reporting knee injuries as a common adverse event. Whether it suits your specific knee condition depends on your history. Talk to your doctor, and see low-impact exercises for men with bad knees for alternatives.
Does it improve VO2 max?
The Nemoto 2007 RCT found 8-9% increases in peak aerobic capacity over 5 months in adults with a mean age of 63. The Karstoft 2013 trial in type 2 diabetics found a 16.1% VO2max gain with interval walking. For what VO2 max predicts and how to estimate yours, see the VO2 max calculator.
What is a good treadmill speed for the brisk phase?
The studies set intensity as a share of each person's peak aerobic capacity, not an absolute speed. On a treadmill, increase your pace until a full sentence requires a breath pause. For most men that lands roughly between 3.5 and 4.5 mph, but your fitness level determines the right number.
Will it help me lose weight?
The Nemoto RCT did not measure body weight. Morikawa 2011 observed BMI and fat reductions pre-to-post, but without a sedentary control group for body composition, attribution to IWT is uncertain. The only RCT that found fat mass decrease (Karstoft 2013) enrolled type 2 diabetics. Interval walking improves fitness; its weight loss effect in healthy men is not confirmed by the available research.
References
- 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 Clin Proc. 2007;82(7):803-811. PMID 17605959
- Morikawa M, Okazaki K, Masuki S, et al. Physical fitness and indices of lifestyle-related diseases before and after interval walking training in middle-aged and older males and females. Br J Sports Med. 2011;45(3):216-224. PMID 19846423
- Masuki S, Mori M, Tabara Y, et al. The factors affecting adherence to a long-term interval walking training program in middle-aged and older people. J Appl Physiol. 2015;118(5):595-603. PMID 25539937
- Karstoft K, Winding K, Knudsen SH, et al. The effects of free-living interval-walking training on glycemic control, body composition, and physical fitness in type 2 diabetic patients. Diabetes Care. 2013;36(2):228-236. PMID 23002086
Consult your healthcare provider before starting any new exercise program, particularly if you have cardiovascular disease, joint problems, or other medical conditions.
References
The sources this article links to, in the order they appear.
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Medical Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult your healthcare provider before starting any new exercise, nutrition, or supplement program. Written and reviewed by The PrimeVital Desk.