I often talk about how much of IG HIIT isn’t actually HIIT, and more so circuit training on here.

While circuit training is totally ok true HIIT training or SIT (sprint interval training) as defined in science (Slide 2) is short to moderate (6-4 min) bouts of exercise above ones anaerobic threshold which is the point of which shit gets HARD. Or >85% VO2 or HR max as defined other places.⁣

A bit of a more nerdy post 🤓👉🏻I’ve compiled 3 research reviews here to break down all the claims people make on HIIT (which, must be true HIIT 😉).⁣

Is it SUPER FAT BLASTING? Possibly! It appears that people doing MIT (moderate intensity training) VS. HIIT lose around the same weight but those who engage in HIIT lose more fat mass! BUT it’s difficult to prescribe due to lack of consistency in protocols, may be more risky for under trained populations & less enjoyable for adherence because well it’s just HARD.⁣

Ok but why does it have these benefits vs Moderate intensity Exericse? It appears HIIT has performance and/or fat oxidation advantages due to proposed mechanisms that involve greater muscle recruitment + stress leading to more robust downstream improvements on our metabolic and “fat burning” machinery aka my beloved mitochondria.⁣

This basically looks like more exercise stress 👉🏻 improved mitochondrial enzymes and proteins involved in fat break down 👉🏻 more powerful capacity to use oxygen and thus burn fat (vs carbs). This can allow us to recover better, push harder and yes may be protective for health by increasing daily fat oxidized!⁣

While traditionally these exercises are done in cardio modalities I think depending on the exact workout and more importantly HOW HARD YOU ARE WILLING TO PUSH you are achieving similar adaptations to your crossfit/orange theory/“functional” style training.⁣ (See my other posts on this topic).

The key is often a some how aerobic morality even w/ weights, threshold pushing, ass kicking and more often SIMPLE workout. Which is why I poke fun at fitspo HIIT🤪.⁣

As always — you don’t need to do this DAILY for these benefits. 1-2x/week is plenty along with other cardio!

Hey, I'm Lyss!

I’m Exercise Physiologist, sports nutritionist, weight lifter, and ultra runner. I am here to bring science to your training in a no-nonsense way. I have helped thousands of women crush big lifting goals, cross race finish lines, and even do both. I’m here to help you do the same!

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Exercise Scientist, ultra runner, lifter, human.