Momentum Issue 52: Do HIIT
Importance
HIIT stands for high intensity interval training. This is in contrast to something like low or moderate intensity or steady-state training, which is where you’re moving at one speed for your whole exercise session.
There are many benefits to doing HIIT, but I will cover three of the main ones here.
1. Lactate
The build up of lactate (what we often mistakenly call lactic acid) that leads to the burning sensation during a HIIT session is actually highly beneficial.
It acts as a fuel source for both the muscles and the brain during intense exercise, and has many positive effects on the brain, such as increasing neuroplasticity (the ability of the brain to change and grow).
This effect has been shown many times to be much greater than the brain benefits that come from more steady-state exercise, such as going for a jog.
2. Fat loss
Probably the most well-known and sought after benefit of HIIT is its ability to help us lose fat.
HIIT usually burns more calories than lower intensity exercise, and increases EPOC (excessive post-exercise oxygen consumption) more than steady state exercise, meaning you’ll burn calories for a longer time after finishing your exercise session.
“With HIIT you become a metabolically efficient, fat-burning machine in far less time than you could through long aerobic sessions…. HIIT significantly lowers insulin resistance and results in a number of skeletal muscle adaptations that cause enhanced muscular fat oxidation and improved glucose tolerance” - Ben Greenfield, Beyond Training
Furthermore, low to moderate intensity cardio doesn’t seem to hugely benefit weight loss, and can actually be harmful to the body:
“While this type of activity may help with stress management, research suggests that it’s useless for weight loss and may in fact be detrimental to health.” - Chris Kresser
3. Mitochondria
Doing HIIT training increases your mitochondrial density
“One of the best types of exercise for boosting your resilience is high-intensity interval training (HIIT). It has a particularly strong hormetic effect on your mitochondria — they become more efficient to deal with the stress, which increases your energy production and slows down aging at the cellular level.” - Dave Asprey
This may be especially important as we age:
“As you get older, you tend to lose mitochondria (in fact, it's a hallmark of aging), which can leave you tired and without the energy to optimally fuel cellular processes. So, by stimulating mitochondrial biogenesis, you can enhance both short- and long-term health.” - mindbodygreen
Implementation
Incorporate some form of high-intensity work into your exercise regime 1-3 times per week.
What is considered “high intensity” will look different for everybody. But the key is to get your heart rate up for short amounts of time, with a decent amount of rest between bouts. Please check with your doctor if you have any concerns about your ability to do this sort of exercise.
There are various forms of HIIT, with different protocols tapping into slightly different systems. I will outline the main ones here.
Tabata - Anaerobic conditioning
Pick a movement that you can do at a very high intensity. Some personal favourites are the assault bike or spin bike, burpees, or the rowing machine. But you can also do:
Jumping rope
Kettlebell swings
Run
Jumping lunges or squats
Pick one movement, go as hard as you can for 20 seconds, then have 10 seconds of rest. Repeat for 8 rounds for a total of 4 minutes.
The key is to go as hard as you possibly can during the 20 seconds.
Little Method - Aerobic conditioning
Again, pick a movement. Go hard for 60 seconds and then go easy for 75 seconds.
Repeat 12 times for a total of 27 minutes.
EMOM - Aerobic conditioning (with resistance work)
EMOM is a CrossFit term and stands for every minute on the minute. This is my favorite type of HIIT.
You pick some movements, anywhere from 3-7, and a required number of reps, and you do each at the start of each minute.
Then once your reps are done, you rest until the start of the next minute, where you start the next movement. I’ll provide an example:
Minute 0: Goblet squats - 15 repetitions
Minute 1: Kettlebell swings - 15 reps
Minute 2: Stationary bike - 20 calories (or about 45 seconds)
Minute 3: Lunges - 16 reps
Etc.
You get a small amount of rest at the end of each minute depending on how quickly you get the reps done, and you can add a minute rest at the end of all the exercises before doing another 1-5 rounds.
If you don’t want to make up your own EMOM, there are various free generators online:
Make your own
You can easily create your own HIIT protocol. Pick an exercise and use anywhere from a 3:1 to a 1:3 work:rest ratio for 3-12 sets.
Keep your exercise bouts between 10 seconds and 90 seconds to ensure the intensity stays high. 10-30 seconds will tap into your anaerobic system and above 30 seconds will target your aerobic system.