HIIT

Exercise Metrics, Activity Type Details, and Training Advice

CategoryCardio
Session10 - 45 min

HIIT alternates hard efforts with recovery periods to create a compact, high-intensity conditioning session. The work intervals are usually short and demanding, so the session can create a strong cardiovascular load in limited time. It is effective, but the intensity makes pacing, recovery, and frequency important.

Exercise Metrics

Fitness Profile [1]

Strength
6
Low-Intensity Cardio (aerobic)
7
High-Intensity Cardio (peak)
10
Mobility & Flexibility
4
Balance
4
Estimated impact of the activity on the 5 key fitness dimensions for longevity.
Based on Bryan Johnson's Blueprint Protocol.

Heart Rate Zones [2]

0
Rest
0 - 49 %
1
Very easy
50 - 59 %
2
Easy aerobic
60 - 69 %
3
Moderate aerobic
70 - 79 %
4
Hard
80 - 89 %
5
Very hard
90 - 100 %
Typical distribution as % of HR max.
Actual values depend on workout intensity, fitness level, duration, and individual physiology.

Activity Type Details

Apple Health label
High Intensity Interval Training
HealthKit reference [3]
.highIntensityIntervalTraining
MET [4]
7 - 11
Typical session duration
10 - 45 min
Recommended fitness level
Intermediate
Injury risk
High

Training advice

Benefits

HIIT is time-efficient and powerful for improving high-intensity repeatability, aerobic capacity, and tolerance for hard efforts. It works best when the hard intervals are truly purposeful and the recoveries are protected.

What to watch out for

This is not an everyday default. Warm up well, keep technique clean, stop if symptoms feel unusual, and leave enough recovery between sessions because intensity multiplies injury and fatigue risk.

Streakout app preview – Summary, Insights & Timeline
Visualize the HIIT workout stats on your iPhone
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Rating
5.0
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Explore other Activity Types in the Cardio category:

[1]
Learn more about fitness longevity dimensions in the "5 Pillars of Exercise for Longevity" resource.
[2]
Learn more about Heart Rate Zones in the "Heart Rate Zones Explained" resource.
[3]
The HealthKit HKWorkoutActivityType value this Activity Type is associated with.
[4]
MET (Metabolic Equivalent of Task) expresses how much energy an activity requires compared with rest. It is commonly used together with body weight and exercise duration to estimate calorie burn.
Disclaimer
The content on this page is for general informational purposes only and not intended as medical advice. Provided metrics are for the most part estimates and might not be based on clinical evidence. The goal is to provide directional guidance and improve the models over time.