Fasting: to exercise or not to exercise?

Fasting is a test of patience and willpower. It takes effort and determination both physically and mentally.

Implementing a training regime without due planning and consideration, during the fast, can be somewhat tricky (ok “regime” sounds a bit harsh, “plan” sounds less aggressive – happy ;) ).

For those of you who want to exercise during the month of Ramadan (Islamic month – in which Muslims fast), consider the information below before you undertake something which may have a detrimental result.

Is it good to exercise whilst fasting?



Very simply, yes!


Now the elaborated answer:

Our blood circulates through the veins and arteries in our body as a direct result of the heart, the blood systems “pump”.

Don’t worry this is relevant I promise!

We also have another system in the body called the Lymphatic System, which is a network of nodes and ducts that are distributed throughout the body (high concentration of these nodes are found in the neck, arm pits, chest and groin). The lymph system carries and transports waste products to the centre of the body, where it can be eliminated.

Now, unlike the circulatory (blood) system the lymph system does not have a pump (e.g. heart), the lymphatic fluid is moved through muscular contractions.

See I told you it was relevant!

This doesn’t mean go and run a marathon or bench press 300kg, it just means that one should engage in moderate activity that will stimulate muscular contractions. This could range from walking, stretching, deep breathing, to exercising a little time before breaking the fast (hence you can replenish your energy stores when you finish training).

If you have time to exercise a little while after you have finished your fast, this would be better. An experiment in the Journal of Applied Physiology found that fasting before exercise increases fat utilisation and lowers the rate of muscle glycogen (i.e. the carbohydrates stored in the muscle) depletion (this information is in relation to fasts that are less than 24 hours and as a result liver glycogen is not depleted – the opposite is true if the fast is 24 hours or more).

A study in the Journal of Nutrition found that the weight loss of a fasting group and that of an exercise (aerobic) whilst fasting group was literally the same (marginal differences), though the group that was fasting whilst exercising lost weight considerably quicker (27 days as opposed to 41 days).

For those of you who were engaging in regular activity before Ramadan, it should be ok to exercise during your fast – though I recommend that you take it easier than usual (i.e. less volume and therefore duration) and to train shortly before you break your fast or a while after. Those who have not been exercising consistently should take up light exercises (e.g. stretching, walking up stairs etc.), gradually increase the intensity (if at all required) and perform them during the fast or shortly before or after breaking the fast (i.e. during the period they can eat).

Getting carried away could result in headaches, vomiting and even passing out, so be very careful. Your body has enough pressure detoxing (i.e. whilst fasting) and if you over exert yourself, you could compromise your ability to fast every day this month.


References available upon request.


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13 Responses to Fasting: to exercise or not to exercise?
  1. zaid
    September 20, 2007 | 3:54 am

    You mentioned in the Study that the group exercising while fasting were engaged in Aerobic exercise, would the results be the same for Anerobic exercise?
    Also If training prior to breaking your fast, would it be advised to break the fast with your usual post workout drink?

  2. admin
    September 20, 2007 | 4:45 am

    The results would probably not be the same, this is due to the fact that when engaged in anaerobic exercise, one would predominantly use a different energy system as opposed to the one in the study (aerobic system).

    Training prior to breaking your fast: yes definitely, make sure the protein in your post-workout drink is hydrolised & also take BCAAs.

  3. Ramadan Links
    August 27, 2009 | 6:08 pm

    [...] Fasting: to exercise or not to exercise? Share and Enjoy: [...]

  4. Shadi
    September 10, 2009 | 9:45 pm

    What about lifting weights? I have been lifting about 3 months before Ramadan, heavily and doing cardio. Now I usually go to the gym about an two hour before sunset and just do 2 hours of cardio burning about 1200-1600 calories; I can do this with ease, however lifting weights is much tougher and takes a lot more out of me. I weighed 246 beginning of Ramadan and now I weigh 237, my end goal is 230lbs but I dont want to lose too much muscle, should I lift weights and cut back on cardio?

    • the health blogger
      April 20, 2010 | 8:12 pm

      Shadi, you can lift weights, however burning that amount of calories during a fasting period (i.e. from the cardio you mentioned you do) is quite detrimental towards maintaining muscle mass. It is important that you concentrate especially on your meals before the fast and when breaking the fast too. Make sure you drink sufficient amounts of water during the period you are not fasting.

    • AJ
      September 18, 2011 | 2:11 pm

      I do weight training 4 days a week and I have been training in a fasted state a few times. I also know of several people who’ve done the same while fading for more than 72hrs. The general concensis is that if you are not losing strength in your lifts then you are not losing muscle. You might lose some size because your muscle will be less inflated as you are not eating but that is purely temporary and superficial. You will lose a ton of fat really fast as you will be forcing your body to use the energy that you have been storing. As the article states; your lymphatic system is driven by muscle contraction, therefore weight training is better for fat loss than cardio. So my advice would be to drop the cardio completely and do an hour of weight training.

  5. BenBillyBobJoeBarneyFrank
    October 20, 2009 | 3:29 pm

    That isn’t a fast if its ramadan…sure exercising is ok since you’re EATING. But during a real fast for any period of time and the advice to exercise is a bad idea.

  6. bridgette
    October 28, 2009 | 11:51 pm

    i am going to fast for just a day (no food or water), 6:15am-6:44pm. i am not sure if this is too dangerous to do because from 3:30-5pm i have conditioning that’s kind of intense. do you think i should fast?

  7. Ramadan
    January 8, 2010 | 9:34 am

    Ramadan is different. You eat tons in the morning and tons at night so it seems like your eating that extra meal.

    • the health blogger
      January 29, 2010 | 4:30 pm

      “Ramadan” – Are you meant to be eating “tons” in the morning and afternoon?

  8. JogWhilstFasting
    April 29, 2010 | 6:00 pm

    I normally jog everyday, or every other day.
    But :-
    1)On a fast day, should i do i light jog? I really don’t see the point in walking although I would if necessary.
    2)Is jogging whilst dehydrated a good idea?

    • the health blogger
      May 20, 2010 | 11:09 am

      JogWhilstFasting, i would refrain from any exercise in which you would have to exert yourself whilst fasting. Pre/post fasting is fine. Jogging whilst dehydrated is not a good idea.

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