What is HIIT?
Mitochondria and fat metabolism
To burn one gram of fat, you need two liters of oxygen.
Our metabolic furnaces
HIIT can eliminate the problem of reduced muscle mass that can occur from spending countless hours performing moderate-intensity aerobic exercise because the higher intensity stimulates a simultaneous increase in muscle mass and mitochondrial capacity. Many scientific studies have shown that HIIT has a great effect on (PGC)-1α, a receptor that is considered the main regulator of mitochondrial biogenesis in skeletal muscle.
Why HIIT and not steady state workout?
It is not a useful comparison to simply calculate the calories burned during each type of workout, because this is not the same as the total energy expenditure resulting from the workout once the post-workout energy consumption (EPOC) is accounted for and does not consider the increase in muscle mass possible by performing HIIT workout regularly over time.
Not only aesthetic benefits but also health benefits
5 benefits of HIIT training
- Increasing muscle glycogen content at rest
- Increasing the ability to use fatty acids
- Improved peripheral vascular structure and function
- Performance improvement
- Improvement of the maximum oxygen uptake
What is the best HIIT protocol for fat loss/ weight loss?
- Range of movement
- Speed of movement
- The complexity of the exercise
- Load added to the exercise (e.g. from a free body squat to one with the rocker arm)
- TUT (Time under tension)
- Amount of muscle mass used in the exercise (e.g. progression from a bodyweight squat to an overhead squat)
How long does a HIIT session need to be to get results?
In part, yes, 20 minutes of high-intensity workout contributes significantly to the consumption of fat mass, if it is accompanied by a correct and personalized dietary program. The central part of the workout cannot have a long duration (> 30-40 minutes) because of it impossible to maintain a sufficiently high intensity to be considered HIIT for this duration. If prolonged, this type of workout can lead to a reduction in the quality of exercise technique with a consequent increase in the risk of injury and potentially reduced recovery adaptations following workouts.
20 minutes of high-intensity work contribute significantly to the consumption of fat mass, provided that it is accompanied by a correct and personalised dietary programme.
Warm up and cool down
Example HIIT workout session plan
- Warm up (10'): Start the workout by performing multi-joint exercises alternating with locomotion exercises (running, walking, jumping, jumping forward, etc.) to mobilize joints, take muscles through a full range of motion, and raise heart rate gradually.
- Main session (20-25'): The choice is vast: For example, Circuits of 6-8 exercises alternating 20-30" of work with 10-15" of rest, or 8 rounds of the same exercise doing 20" of work and 10" of recovery or, a classic interval where you can alternate exercises to run, rowing, jumping rope.
- Cool down (10-15’): Initially continue the workout with a low impact activity. Jogging on the spot may be a choice or even continue the previous circuit at a significantly decreased intensity. Always leave 5' for stretching and relaxation exercises at the end of the workout.
- Cao M, Quan M, Zhuang J, Effect of High-Intensity Interval Training versus Moderate-Intensity Continuous Training on Cardiorespiratory Fitness in Children and Adolescents: A Meta-Analysis.
- Nicolò A, Montini M, Girardi M, Felici F, Bazzucchi I, Sacchetti M, Respiratory Frequency as a Marker of Physical Effort During High-Intensity Interval Training in Soccer Players.