Research Says It Only Takes 11 Minutes For Your HIIT Workout To Reach Its Peak
If you've been skipping cardio because you can't imagine squeezing in another 45-minute workout, new research has arrived with good news. You may need way less time than you think to hit reach your cardio peak.
A new meta-analysis1 found that high-intensity interval training (HIIT) delivers the majority of its heart-health benefits in a fraction of the time it takes moderate-intensity cardio to do the same. In other words, that quick, hard effort that you do because you feel guilty about skipping the long run might actually be the smarter move.
About the study
Researchers pooled data from 69 randomized controlled trials involving 2,387 participants to compare HIIT and moderate-intensity continuous training (MICT), the classic steady-state cardio most of us grew up with. For most people, that looks like a comfortable jog on the treadmill or brisk walk through the park.
Their goal was to map out the dose-response relationship between exercise duration and cardiorespiratory fitness. In other words, how much benefit you get from your workout as duration increases. Rather than just asking "which is better," the researchers wanted to know how much time each approach actually needs to produce meaningful fitness gains, and where the payoff starts to level off.
The 11-minute finding
HIIT sessions reached 80% of their maximum cardiorespiratory fitness benefit at around 11 minutes per session. Moderate intensity cardio sessions needed about 52 minutes to hit that same relative benefit, amounting to a 4.6-fold difference in time investment.
That means a short, effortful interval session can get you almost the same fitness payoff as a nearly hour-long steady cardio session. If you've been skipping your cardio because you "don't have the time," this research provides a compelling reason to reconsider.
Why more isn't always better
For HIIT, the payoff effect tapered off at about 23 minutes per session. Past that point, adding more interval time did little for fitness. And when the researchers counted only the hard efforts—excluding the recovery periods between them that are built into HIIT training—gains flattened at roughly 10 minutes of high-intensity work per session.
Moderate intensity training behaved differently. Within the durations the trials actually tested, its benefits kept climbing in a straight line and never flattened out, so the researchers couldn't rule out further gains from even longer moderate sessions.
That difference matters when you're budgeting a week of workouts. With intervals, the biggest gains happen early, so stretching a session well past the 20-minute mark buys you less than you'd expect for the effort. But if you enjoy a long run and have the time, pushing yourself to go the extra mile will pay off.
Putting this into practice
Steady-state cardio still works, especially for people who genuinely enjoy a longer, more moderate pace. But if you have putting off cardio because of a lack of time, this research suggests you don't need to sacrifice an hour to get meaningful cardiorespiratory benefits. Short, higher-effort intervals can be a legitimate stand-in for longer cardio sessions.
If you want to try this more time-efficient approach, here's how to start:
- Warm up first: Spend 3 to 5 minutes on easy movement, like walking, light cycling, or bodyweight exercises, to prep your body for the more intense effort.
- Alternate work and rest: Aim for short bursts of hard effort (30 seconds to 1 minute) followed by recovery periods of similar or slightly longer length. A simple starting ratio is 1:1 or 1:2 work-to-rest.
- Start with 10 to 15 minutes of intervals: This range aligns with where this research found the biggest fitness returns.
- Cool down: Spend a few minutes bringing your heart rate back down gradually. If it feels right, return to the easy movement you did in your warm up.
- Build up gradually: If you're new to higher-intensity training, start with lower-intensity intervals, like brisk walking bursts, before progressing to sprints, cycling sprints, or circuit-style intervals.
As with any new exercise approach, check in with a doctor first if you have underlying heart or health conditions, since interval training does ask more of your cardiovascular system in short bursts.
The takeaway
A packed schedule doesn't have to mean skipping cardio altogether.
This research shows us that a well-structured 10 to 15 minute HIIT session delivers most of the fitness benefits you get from a much longer steady-state workout, in a much more efficient manner. Even with a short warm up and cool down, this workout can be completed in just 20 minutes. So if time has been your biggest obstacle, this knowledge might be what you need to make cardio feel doable.
