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Fasted HIIT Workouts Burn More Fat

High Intensity Interval Training sessions, AKA HIIT, are fast and can help you burn more fat while getting your cardiovascular system in shape. When HIIT is combined with good nutrition and intermittent fasting, the results can be transformational.

HIIT workouts comprise of intense sets of varying degrees of difficulty in bursts including heavy, medium, or light resistance with a fast, medium, or slow pace, or any number of combinations of both resistance and speed.

For example, HOTWORX provides three 15 minute HIIT workout types including infrared cycling, a total body resistance bike with upper body levers and lower body pedals, and a patented dual independent handle rower (the only one of its kind and exclusive to the HOTWORX franchise) known as the Thunder Row. Each of the workouts use HIIT as the training format led by a virtual instructor queuing clients to perform three different levels of intensity intervals throughout the short sessions.

The advantage of HIIT is the level of calorie burn and the accelerated fat burn that it generates.

One study noted that, “…results indicate that short-term low volume HIIT can increase aerobic capacity and fat oxidation during submaximal exercise.” (1) It has been found that the increased fat oxidation produced by HIIT is caused primarily from the peripheral adaptations from improved mitochondrial composition and function.

Mitochondria are the powerhouses within the cells that are responsible for producing energy in the form of ATP (adenosine triphosphate). Here's how HIIT can impact mitochondrial function and fat burning:

Increased Mitochondrial Biogenesis: HIIT involves short bursts of intense exercise followed by periods of rest or low-intensity exercise. This type of training can stimulate the production of new mitochondria within cells, a process called mitochondrial biogenesis. More mitochondria mean a higher capacity for energy production, leading to enhanced fat oxidation and overall improved metabolic function.

Enhanced Oxidative Capacity: HIIT can improve the oxidative capacity of muscles. Oxidative capacity refers to the ability of muscles to utilize oxygen for energy production. HIIT increases oxygen consumption during and after exercise, which stimulates the mitochondria to work more efficiently and burn more fat for energy. The calorie after-burn following a HIIT session is more effective than that of other forms of workouts.

Increased Enzyme Activity: HIIT can elevate the activity of enzymes involved in fat oxidation. For example, enzymes such as citrate synthase and dehydrogenase (HAD) are responsible for promoting the breakdown of fatty acids within mitochondria. HIIT can up-regulate the expression of these enzymes, leading to improved fat utilization. The increased demand for energy caused from HIIT triggers this up-regulation. HIIT causes lactate accumulation which can stimulate the expression of enzymes that are involved in both anaerobic and aerobic energy pathways, including those responsible for fat oxidation.

Improved Insulin Sensitivity: HIIT can enhance insulin sensitivity, which means your body becomes better at using insulin to control blood sugar levels. Insulin resistance is often associated with obesity and metabolic disorders, and improving insulin sensitivity can aid in fat loss and metabolism regulation.

Elevated EPOC (Excess Post-Exercise Oxygen Consumption): HIIT can create a phenomenon known as “after-burn," where your body continues to burn calories and fat even after the workout is completed. This is due to the increased oxygen consumption required to restore the body to its pre-exercise state. The elevated EPOC following HIIT contributes to additional calorie and fat expenditure.

Hormonal Changes: HIIT can trigger the release of hormones like epinephrine and norepinephrine, which are involved in the regulation of fat breakdown and energy expenditure. These hormones can stimulate lipolysis (the breakdown of fats) and increase metabolic rate, leading to greater fat burning.

Many proponents of infrared saunas suggest that they aid in detoxification by promoting sweating. Studies have shown that infrared sweat contains 7X more toxic waste than that of a traditional sauna. Sweating helps to eliminate waste products and toxins from the body, which can indirectly support metabolic processes related to fat burning.

Now you know the science of infrared HIIT fat burning. What about actual results? I have witnessed spectacular fat burning results from numerous HOTWORX clients and for myself from only the infrared HIIT. Imagine when HIIT, especially infrared HIIT, is combined with proper nutrition of a balanced diet and intermittent fasting. The results are stellar!

Now is the time to incorporate HIIT training with infrared for fat burning. Don’t miss out on the incredible results!


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Stephen P. Smith, MA
CEO and Creator of HOTWORX, Author, Former National Collegiate Bodybuilding Champion and Arena Football Player, Certified Professional Trainer


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