For many people, intermittent fasting can be a lifesaver when it comes to controlling your food intake. It’s numerous benefits make it a great choice for many people. As you know, cardio is also highly beneficial and should be a central tenet of any weight loss or fitness program. But when you’re intermittent fasting, when exactly should you do your cardio?
For most types of Intermittent Fasting (IF), the best approach is to do your cardio 1-2 hrs after breaking your fast. Provided that you don’t eat too much early on during your eating window. This will work for anyone doing 18/6 or 16/8. Simply break your fast with a healthy but light meal or snack, maybe 200-400 calories, then wait about an hour then do your cardio. This way you will have more energy to have a more intense cardio workout, and you’ll reduce muscle breakdown.
This one-size-fits all approach doesn’t make sense for those who eat one meal a day, or prefer the 5 days/2 days format of intermittent fasting. There are a few considerations when planning on how to integrate your fasting schedule with your cardio workouts, so let’s explore them a little.
What Type Of Intermittent Fasting Are You Doing?
The major types of intermittent fasting are:
- 16/8 (Hours)
- You fast for 16 hours, then eat all your calories for the day within the remaining 8 hours.
- 18/6 (Hours)
- Fast for 18 hours, eat within 6 hours.
- OMAD (One Meal A Day)
- Exactly what it sounds like.
- 5/2 (Days)
- Eat normally for 5 days out of the week, fast for 2 non-consecutive days per week. Some variations suggest eating up to 500 calories on fasting days, but I’d recommend fasting the entirety of both days.
For 16/8 the above advice fits well. For example, you fast from dinner (ending at 8pm) until lunch (12pm) the following day, You do your cardio late afternoon. You’ll be in a fed state, but not stuffed full of dinner yet. Your body will have plenty of readily available blood sugar to supply your muscles with glycogen and allow you to push yourself harder.
On the 18/6 plan, the one I usually do myself, you go a little longer after lunch time, to about 2-3pm, then eat a light sandwich, or a salad, maybe egg and spinach, nuts and raisins, whatever nutritious but light food you enjoy to break your fast. Keep the calories low but give your body some healthy fuel. Around 4pm you’ll be primed for a good, fast and intense training session.
For those practicing OMAD, the choice is less clear. Obviously you don’t want to do your cardio right after your only meal of the day (which will probably be quite large). If you perform your cardio during the middle of your fast, you will probably be more fatigued afterwards – and it may make your hunger harder to handle.The best strategy with OMAD style intermittent fasting is to do your cardio at the end of your fast. This way, you put your body in a final calorie burning frenzy at the end of the fast, but then immediately rewards it with much needed refueling.
On 5/2, it’s best to do your cardio during the 5 normal eating days. If you must do cardio during the fasting days, do it right before you eat your 500 calories or whatever small number of calories your plan instructs. If you are truly fasting during those 2 days, keep any cardio at a low intensity (i.e. walking, leisurely cycling, golf) so as not to get overly fatigued or tempted to break your fast prematurely.
Should You Do Cardio At The Beginning Of Your Fast?
Some people prefer to have their eating window in the first part of their day, from breakfast to lunch. In this scenario, you might want to do your cardio late afternoon, a few hours after your last meal.
This is OK, I mean it works. But is not really ideal for most people because the exercise will make you hungrier than you would normally be, fairly early into your fast. This may lead to trouble sleeping, or greater temptation to end your fast prematurely.
If you really want to be sure that you are actually progressing, then you need to be monitoring your body fat. just because you’re losing pounds doesn’t mean you’re getting less fat, you could be losing lean mass. Conversely, if you’re trying to ‘bulk up’ you may think that you’re gaining muscle, but you could actually be gaining more fat than you realize. To be sure, check out this Omron handheld body fat reader available on Amazon. This is the one I have at home and I use it regularly to give me a clear and accurate reading of my body composition.
What If You Do Cardio Mid-Fast?
Doing your cardio in the middle of a fast may not be optimal, but sometimes you just have to do cardio whenever you can fit it into your schedule, which is admirable. So if this is your only option, of course, go for it! Doing some cardio is always better than doing no cardio!
Try to push the cardio session as far back into your fast as you can, so you don’t have too long to wait to eat afterwards.
For some people, their cardio provides a distraction from the hunger that they may be feeling. Exercise is also a good, albeit temporary, appetite suppressant.
Should You Do Cardio At The End Of Your Fast?
This is undoubtedly the best time to do your cardio if you are practicing OMAD, or 20/4 or any of the formats that have a very short eating window. This way, you will be able to replace your energy stores and get some fresh amino acids in your system right after you do that your cardio.
Even for 16/8 and 18/6, you will sacrifice some performance by doing your cardio before you have broken your fast, but this is the second best time to do it.
Do You Even Need Cardio When Intermittent Fasting?
IF is a great way to control your eating tendencies. Unfortunately, I have always been a binge eater, and, for me, having a small eating window is an effective way of helping me keep within my appropriate daily calorie intake.
At the same time, I enjoy knowing that I am benefiting in many other ways from the extended fast each day.
Fasting for 13 or more hours per day has a ton of benefits – aside from weight loss. These include giving your digestive system a rest, cleansing virtually all your cells through autophagy, and possibly even extending life!
Although an active lifestyle will certainly help, you can still lose weight by intermittent fasting alone, without exercise. The point is, not only will doing some cardio speed up your results tremendously, the added benefits of the exercise for your heart and lungs, muscles and bones, as well as your brain and mood, add up to something that you really should do for yourself. So keep fasting, but get some cardio in there at the right time.
Summary Table
| TYPE OF INTERMITTENT FASTING | WHEN TO DO CARDIO |
| 16/8 | During beginning of eating window |
| 18/6 | During beginning of eating window |
| 20/4 | End of fasting window |
| OMAD | End of fasting window |
| 5/2 | On non-fasting days |
Related Questions:
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