How Useful Is “Exercise Snacking”, Really?

“Exercise snacking” refers to doing a very small amount of exercise at a time.

For example, there was an article: Want the health benefits of strength training but not keen on the gym? Try “exercise snacking”

Which may well prompt you to wonder: what’s the minimum that still has benefits?

Let’s HIIT it!

We’ve talked before about High-Intensity Interval Training (HIIT):

How To Do HIIT (Without Wrecking Your Body) ← important, because the “high-intensity” part can cause problems for some people, if not undertaken attentively

Which can further be expanded to: HIIT, But Make It HIRT ← high-intensity resistance training, undertaken per HIIT principles

Now, HIIT is usually done in one of two ways:

1. One minute intensive exercise, one minute rest, repeat
2. Continual moderate exercise, with periodic one-minute intense bursts

There are other protocols, but those are most common. If you’re curious about optimization, by the way, check out: 53 Studies Later: The Best Way to Improve VO2 Max

…which yielded neither of the above, but rather:

1. 15×15 Interval Training: 15 seconds sprint (90–95% max heart rate) + 15 seconds active rest (70% max heart rate), repeated 47 times.
2. 4×4 Interval Training: 4 minutes sprint (90–95% max heart rate) + 3 minutes active rest (70% max heart rate), repeated 4 times.

(see the above link for more details)

However!

Scientists have now examined what would happen if we just do 1 minute of intense exercise per hour, over the course of 10 hours.

The study

It’s not the only thing that the researchers (Dr. Monique Francois et al.) investigated, either; they also looked at what’d happen if you just did 2.5 minutes of moderate exercise per hour, for 12 hours.

The protocols:

• High-Intensity Interval Training (HIIT): 1 minute on a treadmill at 85–95% of maximum heartrate on a treadmill, once per hour for 10 hours, on alternate weekdays
• Intermittent Sedentary Interruption Training (ISIT): 2.5 minutes walking, once per hour for 12 hours, each weekday
• HIIT+ISIT (Combo): doing both of the above

Other considerations:

• Participants were asked to keep their daily step count under 5,000 steps per day, other than their mandated exercise
• They wore continuous glucose monitors (CGMs), and were also tested for blood flow, arterial stiffness, and cardiorespiratory fitness

What they found:

• Blood flow improved significantly after the combination of both protocols
• VO2 max improved significantly after the combination of both protocols
• VO2 max improved significantly, but more modestly, after the HIIT-only protocol compared to ISIT only
• There were no significant differences in blood glucose or arterial stiffness

The latter is reasonable, given it was quite a short intervention (two weeks).

Limitations:

This was not only a short study, but this was also very small (n=11). However, we’re not going to write it off based on the small size of the study, because the method was good (if you read the paper below, you’ll see what we mean), and this effectively means the equivalent of 11 case studies that agree with each other—which starts to look like a trend that’s at least worth attention.

Of course, we would love to see the experiment repeated with a larger sample (and indeed, the researchers themselves call for this too).

You can read the paper in its entirety here:

Low-intensity activity breaks combined with alternate day interval training mitigate cardiovascular effects of sedentary behavior

In summary

In short: it helps!

Breaking up prolonged periods of sitting is very important for health, and/but actually exerting one’s heart, even if just for one minute per hour, over the course of 10 hours, 3x per week, makes a significant difference to cardiovascular health.

Want to learn more?

Check out:

Stand Up For Your Health (Or Don’t) ← this is about reducing the damage done by sitting, including if for whatever reason you have to spend a lot of time sitting, including if you physically cannot stand and/or cannot walk.

Take care!