HIT/HIIT has been the lovechild of the fitness industry for a few years now.
The prevailing concept behind it is that not only can you get a higher volume of work done in more time (which is great for time poor individuals) but you gain specific advantages which aren’t found in traditional, steady state cardio.
There ARE benefits to doing higher volume, higher intensity training. Greater type 1 muscle fibre hypertrophy, greater mitochondrial density, increased uptake of fatty acids into the Krebs cycle, an improvement to your VO2 max, a higher capacity for higher volume work and greater cellular respiration. (Fancy term for saying you utilise energy faster and more efficiently!)
So whilst there are definite metabolic advantages to higher intensity work, this isn’t necessarily going to result in “fat burning.”
High intensity training, by it’s very nature – can be difficult to recover from.
It’s higher energy demand means that glycogen can be depleted quickly and some styles of HIIT and sprint training can really tax the large muscle groups of the legs. Adding sprints to an already significant leg training schedule can interfere with increases in strength and can increase recovery demands considerably.
As most gen pop people are already terrible at getting enough sleep, nutrient density, hydration and “calming the fuck down-ness,” it can be a detriment when used too much, at the wrong time or by the wrong person.
High intensity training can also be dangerous if you’re doing it without a base level of fitness.
Being part of a crowd doesn’t help here, ie max rep squats” and burpees done with a back that looks like the treble clef at your local F45. A greater amount of fatigue, either via cardiovascular or strength based means, increases risk of injury.
WHAT REALLY DRIVES FAT LOSS
Ultimately, what comes down to fat loss or no fat loss is energy balance.
Whilst HIT / HIIT can have the benefits of getting higher calorie burns in less time, do we even necessarily want to burn “max calories?”
After all, a calorie deficit created through diet needs NO TIME in your day.
A calorie deficit created through diet PLUS “maximal calorie burn” through exercise can actually reduce your calorie deficit because you’ll adapt to it.
The more calories you expend, the more you tend to compensate by eating, moving less and doing less “stuff” for the rest of the day. There seems to be a genetic or behavioral predisposition by some towards this compensation pattern, and we don’t know why yet.
Furthermore, lean people are more likely to eat more in response to increased exercise than obese people. So if you’re already lean and trying to drop more bodyfat, addressing the consistency and suitability of your diet becomes even more important than physical exercise.
Compensatory mechanisms to energy deficits such as lowered leptin, increased cortisol response, impaired recovery, reduced NEAT and increased cravings for food can spur on a fat loss plateau.
Potentially for some people, BACKING OFF the intensity of exercise would be a far better option.
Unfortunately those without a coach or experienced trainer in their corner think that MORE smashing, more frequency, harder, longer sessions is the way to go.
This is the equivalent of digging yourself a hole, and trying to get out of it by digging faster.
WHAT DOES THIS MEAN?
Essentially it’s further proof that there is no “one size fits all” strategy.
A blanket statement that higher intensity exercise burns fat is clearly not the case.
Although there are some metabolic benefits to be had by higher intensity training, it’s not a magic bullet.
A coach can help you to ascertain if this is the right course for you and ultimately, your enjoyment of this style of training, your time available to train and your personal circumstances are integral.
So whilst yes, you may burn more calories doing HIIT and you may enhance certain mitochondrial and metabolic functions doing so, X does not always lead to Y.
HOW IS YOUR CURRENT APPROACH GOING?
Do you use HIT/HIIT? Is it working for you?
Get in touch if you’d like to chat about your current approach, and to investigate some alternatives if it’s not getting you the results you expected.