All Hits, No Misses: How Intemittent Fasting and HIIT Workouts Can Help You with Your Fitness Goals
August 10, 2015 | 15,921 views
By Dr. Mercola
When it comes to achieving your fitness goals, it is always important that you make good decisions when it comes to your diet and exercise routines.
This is where I find intermittent fasting to be extremely useful. Encouraging you to eat healthy without depriving yourself, intermittent fasting is a strategy that allows you to consume regular meals at specific hours of the day – for example, skipping your breakfast, having your lunch a little earlier and your dinner no later than 7:00 PM, and not eating anything at least three hours before you go to bed – to turn on your body’s fat-burning mode.
Aside from being effective at weight management, studies have shown that intermittent fasting has additional health benefits, such as:
- Normalizing your blood pressure, LDL, total cholesterol levels, body weight in obese individuals, and oxidative stress
- Improving the circulation of glucose and lipid levels, metabolic efficiency and body composition, pancreatic function, insulin levels and insulin sensitivity
How Exercising in a Fasted State Helps You
Exercising while fasting is crucial to your fitness plans as it allows your body to effectively shed fat, thanks to your sympathetic nervous system (SNS), which controls your natural fat-burning processes. SNS is activated by exercise and lack of food. This combination of fasting and exercise maximizes the impact of cellular factors and catalysts (cyclic AMP and AMP Kinases), which force the breakdown of fat and glycogen for energy.
In a study published in The Journal of Physiology, 28 healthy men aged 18 to 25 years old were divided into three groups. The first group exercised before eating a carbohydrate-laden breakfast and drank water only during the exercise. The second group did the same but drank sugary drinks while working out. The last group ate the same diet but did not exercise. Running and cycling at a strenuous intensity for four times a week were their forms of exercise.
The results showed that the last two groups gained weight (ranging from three to six pounds) and developed insulin resistance. Only the first group did not gain any weight and showed no signs of insulin resistance, rendering their fast before working out effective.
Another perk of exercising in a fasted state is that it helps ensure that you don’t wear out your active muscles (which are the ones used during workouts) via a preservation mechanism.
A little caveat: Fasting, or exercising in a fasted state, would be unwise if you're still eating a diet full of processed foods. Addressing your diet is absolutely crucial before you venture into any kind of fasting. Also, when undertaking any kind of calorie restriction, such as intermittent fasting or simply skipping breakfast, it's critical to cut the right calories, namely carbohydrates (those from sugars and grains that is, NOT vegetable carbs).
The Benefits of High-Intensity Interval Training
Making nutritious choices is but one component when it comes to achieving your fitness goals. There has to be the right kind of exercise and physical activity as well to keep your body moving.
If you’re doing intermittent fasting, high-intensity interval training (HIIT) is best for you. According to the American College of Sports Medicine, HIIT workouts involve repeated bouts of high-intensity effort followed by varied recovery times, ranging from five seconds to eight minutes long. These workouts – which could involve cycling, walking, swimming, running, and various group exercises – are performed at 80 to 95 percent of a person’s estimated maximal heart rate. Most exercises target the legs, arms, and thighs.
Other than allowing you to burn more calories in less amount of time, HIIT workouts have shown to produce greater health benefits overall than conventional aerobic training, as well as the ability to naturally increase your body’s production of human growth hormone (HGH) also known as the “fitness hormone.” HGH promotes muscle, effectively burns excessive fat, and plays an important part in promoting overall health and longevity.
How to Start Your HIIT Workout
Intensity is key for reaping all the benefits HIIT can offer. To perform it correctly, you'll want to raise your heart rate to your anaerobic threshold, and to do that, you have to give it your all for those 20- to 30-second intervals. Different studies will use different intervals of exertion and recuperation.
I personally use and recommend Peak Fitness Training, which is a simple and easy-to-follow workout developed by Phil Campbell. Here's how a typical HIIT workout is done using an elliptical machine:
- Warm up for three minutes.
- Exercise as hard and fast as you can for 30 seconds. You should be gasping for breath and feel like you couldn't possibly go on another few seconds. It is better to use lower resistance and higher repetitions to increase your heart rate.
- Recover for 90 seconds, still moving, but at slower pace and decreased resistance.
- Repeat the high-intensity exercise and recovery seven more times.
When you're first starting out, depending on your level of fitness, you may only be able to do two or three repetitions of the high-intensity intervals. As you get fitter, just keep adding repetitions until you're doing eight during your 20-minute session.
Given the nature of these workouts, I advise you to take a fitness test or a medical clearance from your physician first, especially if you have an existing medical condition.
For more information about high-intensity interval training and how it boosts the benefits of intermittent fasting, read my article “High-Intensity Interval Training and Intermittent Fasting – A Winning Combo for Fat Reduction and Optimal Fitness.”
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