Improve VO₂Max with interval walking

Interval walking alternates periods of brisk and slow walking. It does not require running or a special venue, making it an accessible next step for people who already walk regularly. Many studies have involved middle-aged and older adults in Japan.

What the studies found

A 5-month randomized controlled trial (Nemoto et al., 2007)

• Participants: 246 adults, mean age 63 (60 men and 186 women), were randomized to three groups. The analysis included 139 participants across the groups, including 42 in the interval-walking group. It did not include everyone randomized.
• Three groups: (1) no walking training; (2) continuous moderate walking at about 50% of peak oxygen uptake, at least 8,000 steps a day on at least 4 days a week; and (3) interval walking, alternating 3 minutes slow and 3 minutes brisk for at least 5 sets a day on at least 4 days a week.
• Results: Among the analyzed interval-walking participants, peak oxygen uptake estimated from accelerometer data during walking increased by 9%, while peak oxygen uptake measured by respiratory gas analysis during cycling increased by 8%. Thigh strength also increased: knee-extension strength by 13% and knee-flexion strength by 17%. All of these improvements were greater than in the continuous-walking group. The reduction in resting systolic blood pressure was also greater in the interval-walking group.
• Adherence: Among those assigned to interval walking, 11 of 19 men and 31 of 68 women met the prescribed targets. Maintaining the routine was not easy even in the study.

Five months in 679 people (Masuki et al., 2019)

• This study analyzed 679 participants, with a mean age of 65, who completed 5 months of interval walking. Estimated peak oxygen uptake increased by an average of 14%, while a lifestyle-related disease score used in the study fell by 17%. These were changes within participants before and after the program, not comparisons with a non-exercising control group.
• In this group, more weekly brisk-walking time was associated with larger improvements up to about 50 minutes, after which the relationship plateaued. Slow-walking time and total walking time did not show a positive association with improvement. Participants were not assigned to different walking durations, so this does not establish 50 minutes as an optimum or upper limit for everyone. Nor does it mean slow-walking intervals are unnecessary.

A review describes interval walking as effective for improving fitness and muscle strength. Adherence is high in short-term studies, but long-term adherence remains a challenge (Karstoft et al., 2024).

The walking protocol used in the study

1. 3 minutes of slow walking: approximately 40% of peak oxygen uptake during walking.
2. 3 minutes of brisk walking: above 70% of peak oxygen uptake during walking.
3. Participants were instructed to repeat this 6-minute set at least 5 times a day (at least 30 minutes), on at least 4 days a week, for 5 months (Nemoto et al., 2007).

The 3 + 3 minutes above follows the abstract. The full text describes 2–3 minutes of slow walking and 3 minutes of brisk walking, with brisk intensity above 70% and below 85% of peak oxygen uptake during walking. The study used individually set intensities and records from devices such as accelerometers. Heart rates from consumer smartwatches or a “somewhat hard” feeling cannot simply be treated as the same intensity. The times and intensities above describe research conditions, not a ready-made starting program for beginners.

Before adding interval walking

• If you do not exercise regularly, start with short periods of easy walking and build up gradually. You do not need to meet the study's frequency from the start (MHLW, 2023).
• Check how you feel on the day and how tired you are the next day. If tiredness interferes with everyday life, rest and reduce the intensity or amount next time.
• If you have a medical condition, take medication or have symptoms that concern you, consult your doctor first. If you are unsure about an appropriate intensity, also consult an exercise professional.

Exercising safely

• If you have knee or lower-back pain, consult your doctor first. Start at low intensity for short periods, and stay within a pain-free range (MHLW 2023, INFORMATION 4).
• Stop immediately if you develop chest pain, cold sweats, palpitations, dizziness or unsteadiness during exercise.
• Drink regularly in hot weather, and do not push yourself on days with a heatstroke alert.

See Starting safely for checks before exercise, or Compare exercise methods for other approaches.