Fasted cardio is a buzz term in fitness. So, what is it and why is it gaining popularity?
Fasted cardio, or fasted training in general, can be defined as working out during a period of non-eating and restricted liquid intake. Training during a fasted state is gaining popularity because of the results that can be obtained, namely fat loss as the most desired outcome.
“Fat is the main fuel source used during exercise when fasting…” (1)
When carbs are depleted from fasting, workouts burn fat on an empty stomach. Fat loss is not the only benefit, though. Athletes will be happy to know studies have shown that V02 max, a measure of endurance, increases over time in response to fasted training.
Fasted training can get you to ketosis faster than diet alone.
“If you are following a low-carbohydrate diet and aren't reaching ketosis or having symptoms, high-energy activities like sprinting or high-intensity interval training (HIIT) will quickly use up your glucose stores so you reach ketosis quickly.” (2)
Analysis of fasted training research suggests that quick workouts during a fasted state are preferred over longer periods of training to avoid fatigue from extended training time. In other words, don’t overtrain. Additionally, quick infrared HIIT workouts can yield a higher and longer workout calorie after-burn without the likelihood of overtraining.
In 2016 an analysis and review of numerous studies was performed by the National Center for Biotechnology Information, and it was found that there was a significant increase in fat oxidation among subjects who worked out in a fasted state versus a fed state. The review resulted in this declaration: “We conclude that aerobic exercise performed in the fasted state induces higher fat oxidation than exercise performed in the fed state.” (3)
I would recommend fasted workouts in the mornings to get your day started, and/or fasted training around noon before eating while using an amino/eloctrolyte powder or gummy with your water during these lunchtime fasted workouts. The calories from these powders are negligible, but this will increase your workout performance and recovery after 16 hours of fasting.
Morning fasted workouts are ideal if you wait to eat until lunchtime. Studies have shown that waiting 2-3 hours to eat after training in a fasted state increases levels of growth hormone. I find that it is easier to wait until noon to eat and that I can benefit from the increased GH immediately following the workout during the hours leading up to the first meal at noon.
In the same way that combining heat with infrared energy for your workout increases efficiency, the combination of fasting with your workout can accelerate weight and fat loss with your diet.
Another thing to consider in the choice of what time you should train is your body’s natural circadian rhythm. Good sleep = better health. Most fitness experts agree that early in the day is best for fasted training and good sleep. Morning workouts are preferred to match the circadian clock. Training and/or eating too close to bedtime can disrupt REM and deep sleep.
In my opinion, evening workouts are fine as long as the fasting period begins soon after and if the workout is well before bedtime so as not to interfere with deep sleep.
Fasting increases insulin resistance, optimizes levels of GH, and increases glycogen breakdown. This suggest how important the workout calorie after-burn is during a fasted state. The after-burn leads to higher levels of fat oxidation. Infrared HIIT training generates an intense and longer lasting after-burn. This is why I urge HOTWORX members to use infrared HIIT as a way to utilize the advantages of fasted workouts and from the fasted after-burn (post-workout) elevated metabolism.
Train fasted my friends!