High-intensity interval training and Intermittent fasting both are crucial for a healthy lifestyle. They help you enhance your cardiovascular health and quality of life. In this article, I’ve shared various pros and cons of doing HIIT workouts during intermittent fasting that will help you decide whether you should include them in your lifestyle or not.
HIIT and intermittent fasting are primarily suitable for those trying to lose excess body fats.
And studies also demonstrated that restricted eating is an effective strategy for treating overweight and obesity.1 Welton S, Minty R, O’Driscoll T, Willms H, Poirier D, Madden S, Kelly L. Intermittent fasting and weight loss: Systematic review. Can Fam Physician. 2020 Feb;66(2):117-125 And interval training also has a positive impact on fat loss.2 Boutcher SH. High-intensity intermittent exercise and fat loss. J Obes. 2011;2011:868305. Epub 2010 Nov 24
So, if you want to speed up weight loss, you can do one of them or both. However, HIIT with intermittent fasting together will be challenging. So I suggest you consult your doctor before starting if you’ve health issues or are not confident.
Okay! So let’s find out all about interval training and time-restricted fasting.
You can directly head up to the topic you want to see through the table of content links.
Related: The Best Intermittent Fasting Books
What is High-intensity interval training (HIIT)?
HIIT or High-Intensity Interval Training is a workout program where you have to do one or more workouts in intervals.
In simple words, a training program where you need to perform workouts at a higher intensity with a short time interval between exercises.
Let’s take an example of 10 minutes running HIIT.
- 2 minute moderate run at 75 percent of your maximum heart rate.
- 1 min walk
- 2 minute run at 80 percent of your MHR
- 1 minute recovery period
- 2 minute run at 85 percent of your MHR
- 1 minute Slow walk
- 1 minute run as fast as possible.
You need to do workouts at 80 to 95 percent of your maximum heart rate (MHR) in HIIT.
The duration of the intense-burst activity and the recovery time depends on your fitness levels.
Usually, keeping the recovery period short with a longer activity time yield better results.
Benefits of HIIT
Intermittent training has various health benefits shown in multiple studies. Let’s look at them some of the crucial ones.
- HIIT burns more calories than other forms of workout training.
- It has the “after-burn effect”. It means your body uses fats and burn calories even after the workout (usually till 24 to 48 hours).
- HIIT boosts metabolism and speeds up weight loss.
- It improves bone density and strengthen skeletal muscles.
- HIIT improves VO2peak (the maximum rate at which your body uses oxygen during the work).3 Ito S. High-intensity interval training for health benefits and care of cardiac diseases – The key to an efficient exercise protocol. World J Cardiol. 2019;11(7):171-188
- Interval training are pretty beneficial for heart health in the long run.
- Intense burst interval training also enhance respiratory function, improve blood pressure and maintain insulin levels.
- HIIT is also beneficial for mental health. Doing HIIT on a regular basis keeps your mind active and cultivates new ideas.
What is Intermittent Fasting?
Intermittent fasting (IF) is the time-restricted fasting pattern where you have to keep fast for the selected period followed by an eating window.
Suppose you have decided to follow the 14:10 fasting pattern. It means you’ll have to keep fast for 14 hours straight and consume the foods for the rest of the 10-hour window.
You can complete this fasting schedule according to your lifestyle. For example, if you’re a “9 to 5” office goer, you can have your last meal at 6, and your next will be at 8 in the morning.
You can select the pattern of fasting depending on your lifestyle. There’s no fixed timing; you can do it when it suits you the most.
To get the best result, follow the calorie-restricted diet.
Consume low-calorie food that contains good protein and fills you up for a longer time.
Benefits of Intermittent Fasting
Window-eating (IF) has various health benefits, from weight loss to better heart health.
Let’s look at some of the significant pros backed up by science.
- Intermittent fasting improves certain health conditions such as cardiovascular disease, obesity, diabetes, cancers, and neurological disorders – suggested in an article published on the National Institute of Ageing website.4 De Cabo R and Mattson MP. Effects of intermittent fasting on health, aging, and disease. New England Journal of Medicine. 2019;381(26):2541-2551. DOI: 10.1056/NEJMra1905136
- Restricted eating often results in decreased calorie consumption. And because of this your body uses stored fat for energy that ultimately helps you lose weight.5 Welton, Stephanie et al. “Intermittent fasting and weight loss: Systematic review.” Canadian family physician Medecin de famille canadien vol. 66,2 (2020): 117-125 (PubMed)
- Research also suggests that IF also is an effective way to lower blood glucose and to treat type 2 diabetes.6 Albosta M, Bakke J. Intermittent fasting: is there a role in the treatment of diabetes? A review of the literature and guide for primary care physicians. Clin Diabetes Endocrinol. 2021 Feb 3;7(1):3
Pros of Doing HIIT and Intermittent Fasting Together
Here are the benefits of doing HIIT during the fast.
- A study showed that doing HIIT with Intermittent fasting together may improve the lipid profile. And the better lipid profile lowers the risk of cardiovascular disease, type 2 diabetes, and some forms of cancers.7Abbasi, B., Samadi, A. & Bazgir, B. The combined effect of high-intensity interval training and intermittent fasting on lipid profile and peroxidation in Wistar rats under a high-fat diet. Sport Sci Health 16, 645–652 (2020)
- Doing HIIT exercises during Intermittent fasting lower body fat and improve jumping performance in active adult women (21-33 age) – showed in a study published in NCBI journal.8Martínez-Rodríguez A, Rubio-Arias JA, García-De Frutos JM, Vicente-Martínez M, Gunnarsson TP. Effect of High-Intensity Interval Training and Intermittent Fasting on Body Composition and Physical Performance in Active Women. Int J Environ Res Public Health. 2021 Jun 14 (PubMed)
- Intermittent fasting, with or without HIIT, can be an effective way to prevent weight gain. Both HIIT and IF use fats during any activity or exercise and help you stay in calorie deficit.
- Restricted eating and interval training also reduces the level of insulin and seems to be the important time-efficient strategy for the treatment of type 2 diabetes.
Disadvantages of Doing HIIT Exercise During Intermittent Fasting
Intermittent fasting and HIIT together don’t always work the best for everyone. It also has some downsides which you may know.
- Performing high-intensity workouts during the fasted state may makes you feel uncomfortable. For example, you may feel headache, dizziness, fatigue, low blood pressure and abnormal heart rate.
- Sometimes, post-fasting can reverse the effect of weight loss. Because after a period of fasting, people tend to eat heavy foods which contain high calories. Extreme hunger may leads you consume more calories than you eat without fasting. And as a result, you end up eating more calories than your body needs.
- Some reaserch have also shown that fasting in the long term may slow down your metabolism.
- When you’re in the fasted state, you’ll have less energy. And because of this you wan’t be able to work out as hard as you do in the fed state.
Can You do HIIT with Intermittent Fasting?
Yes, you can do it. However, doing HIIT before, during, or after fasting depends on your fitness level.
Working out in the fed state allows you to do exercises at a higher intensity and for a longer duration.
While working out, during the fasting window help you burn more fats. Because your body will use stored fat for energy.
Exercising before fast will also be ideal for those who want to work out and fast separately and focus on one thing at a time.
And, working out after the fasting period is ideal for those who haven’t got the opportunity to exercise during or before the fasting mode. It will also fit those who want to capitalize post fasting diets.
You can do it whenever suits you the most. Moreover, you can also alternate your workout schedule between the fed and fasting state.
For example, you can work out in the eating window on your first day of fasting. While on the second day, you can do HIIT during the fasting window.
Please, consider the tips below for better results.
- Always listen to your body, just don’t pressurize it.
- Try all three of them for a certain period of time, then do what suits you the best.
- Keep yourself hydrated whenever you do exercises.
The best HIIT Workout You Can Do in the Fasted State
You can do high-intensity interval training during the fasted state if you want to lose weight.
Here is a 20-min workout you do during or post fasting.
- Burpee: 10 reps, 30-sec rest
- Crunches: 20 reps, 30-sec rest
- Jumping Jacks: 30-sec, 45-sec rest
- Leg Raises: 10 reps, 30-sec rest
- Push-ups: 10-20 reps, 30-sec rest
- Bicycle Crunces: 15-20 reps, 30-sec rest
- High Knees: 30-sec, 30-sec rest
- Flutter Kicks: 30-sec, 30-sec rest
- Mountain Climbing: 30-sec, 30-sec rest
- Squats: 15-20 reps, 30-sec rest
- V ups: 30-sec, 30-sec rest
- Lunges: 10 reps, 30-sec rest
- Standard Plank: 30-60 sec, 30-sec rest
- Side Plank: 20-30 sec each side, 30-sec rest
- Alternate Heel Touch Crunches: 30-sec, 30-sec rest
You can save more HIIT workout routines.
- The Best Weekly HIIT Workout Plan
- HIIT CrossFit Workouts And Workout Plan
- HIIT Pilates Workout: Exercises, Routine & Benefits
- The Best HIIT Core Workout Routine
- You can take a pre-workout drinks or snacks that will help you perform well during the exercises.
- Whether you’re in the fasting state or in the normal state, keep yourself hydrated during the workout.
- Avoid strength training while you’re fasting because strength training requires more carbohydrates.
Note: If you’re not an overweight person, there’s no reason to work out while fasting.
Who Should Not Use Intermittent Fasting with HIIT?
Intermittent fasting isn’t for everyone. And you shouldn’t do fasting and HIIT together if you:
- want to increase your weight and gain muscles.
- are pregnant or on breast-feeding.
- are undernourished person.
- have an eating disorder or suffering from Prader-Willi.
- have any health problems.
HIIT and Intermittent fasting are scientifically proven ways to maintain a healthy lifestyle. They lower the risk of heart attack, decrease blood sugars, improve lipid profile, and treat type II diabetes and obesity without medication.
So, if you want to shed some extra pounds safely and effectively, you can do HIIT and intermittent fasting.
However, sometimes they also affect reversely, so you need to manage both of them properly.
Just to add a few points, weight loss is only possible if you consume fewer calories than your body uses throughout the day. And you can do that by eating low-calorie foods that fill you up, fasting, and working out.
Moreover, you can use supplements to speed up your weight loss. I’ve made a list of some best supplements you can include in your diet. So you can check it out if you like.
- 1Welton S, Minty R, O’Driscoll T, Willms H, Poirier D, Madden S, Kelly L. Intermittent fasting and weight loss: Systematic review. Can Fam Physician. 2020 Feb;66(2):117-125
- 2Boutcher SH. High-intensity intermittent exercise and fat loss. J Obes. 2011;2011:868305. Epub 2010 Nov 24
- 3Ito S. High-intensity interval training for health benefits and care of cardiac diseases – The key to an efficient exercise protocol. World J Cardiol. 2019;11(7):171-188
- 4De Cabo R and Mattson MP. Effects of intermittent fasting on health, aging, and disease. New England Journal of Medicine. 2019;381(26):2541-2551. DOI: 10.1056/NEJMra1905136
- 5Welton, Stephanie et al. “Intermittent fasting and weight loss: Systematic review.” Canadian family physician Medecin de famille canadien vol. 66,2 (2020): 117-125 (PubMed)
- 6Albosta M, Bakke J. Intermittent fasting: is there a role in the treatment of diabetes? A review of the literature and guide for primary care physicians. Clin Diabetes Endocrinol. 2021 Feb 3;7(1):3
- 7Abbasi, B., Samadi, A. & Bazgir, B. The combined effect of high-intensity interval training and intermittent fasting on lipid profile and peroxidation in Wistar rats under a high-fat diet. Sport Sci Health 16, 645–652 (2020)
- 8Martínez-Rodríguez A, Rubio-Arias JA, García-De Frutos JM, Vicente-Martínez M, Gunnarsson TP. Effect of High-Intensity Interval Training and Intermittent Fasting on Body Composition and Physical Performance in Active Women. Int J Environ Res Public Health. 2021 Jun 14 (PubMed)