Working out while fasting?

Hi everyone.

I’m going to try incorporating a once weekly 24hr fast just to see what effect it has on my weight loss. My question is to those who do this regularly - do you have a rest day on this day also?

I use a bike turbo trainer 3/4 times a week, do a couple of weight workouts also and walk the dogs every day. I’m just curious as to whether it’s inadvisable to do say my bike session on my fasted day? I have visions of coming off the bike and collapsing with the hunger later on! I will experiment with it of course but am interested in how others have coped or what your experiences may have been with this. (The bike cardio I do is pretty intense, also I will still walk my dogs on my fasted day!)

Cheers!

Replies

  • Geneveremfp
    Geneveremfp Posts: 504 Member
    I do the occasional 24 hour fast - although for different reasons I have an IBD and it gives my colon a rest.

    I find it easiest to eat up until about lunchtime on one day and then start around lunchtime the next day. I've never had a problem with exercising. But I am getting a good number of calories on those days as I'm not doing it for weight loss. I never eat below 1300.
  • petethebest
    petethebest Posts: 6 Member
    I do the occasional 24 hour fast - although for different reasons I have an IBD and it gives my colon a rest.

    I find it easiest to eat up until about lunchtime on one day and then start around lunchtime the next day. I've never had a problem with exercising. But I am getting a good number of calories on those days as I'm not doing it for weight loss. I never eat below 1300.

    Thanks! I guess I should have said - although I’m only realising now - that I mean a 36hr fast. I was confused but thank you for your input. Also I too have digestive issues so I’m hoping a weekly break might help me also.
  • sijomial
    sijomial Posts: 19,811 Member
    edited June 2020
    The context of my fasted exercise was probably a bit different and I'm sure people also simply react and feel differently....

    A very restricted calorie allowance (600) rather than a full fast and also a fasting day followed a day (or days) eating at maintenance (5:2 eating pattern) so going into the fasting day fully fuelled rather than from a deficit. My exercise was sometimes before eating anything that day though.

    At first I found it very hard: raging hunger, light headed, abandoned a couple of fasts. That was even with low calorie burn exercise such as weight lifting or medium calorie burn exercise such as moderate cardio on a Spinning bike.
    Slowly built up the intensity and over a period of quite a few weeks I adapted until fasting day exercise felt just the same as exercising on a normal eating day. I could do a fairly hard hour of cardio or intense weight training with no ill effects.

    Also noticed a difference in my longer duration exercise in that 2hrs hard cycling unfuelled felt the same fed or fasted with no performance detriment. Gave me bigger freedom over making breakfast optional and fuelling strategies for longer rides.

    Think your experiement would be wiser to start with low intensity (zone 2 for example) rather than "pretty intense" on the bike and see how you react. I wouldn't also be too regimented if you simply feel too hungry, abandoning a fast shouldn't really be a big deal - you don't have to suffer to lose weight!
  • petethebest
    petethebest Posts: 6 Member
    sijomial wrote: »

    At first I found it very hard: raging hunger, light headed, abandoned a couple of fasts. That was even with low calorie burn exercise such as weight lifting or medium calorie burn exercise such as moderate cardio on a Spinning bike.
    Slowly built up the intensity and over a period of quite a few weeks I adapted until fasting day exercise felt just the same as exercising on a normal eating day. I could do a fairly hard hour of cardio or intense weight training with no ill effects.

    Think your experiement would be wiser to start with low intensity (zone 2 for example) rather than "pretty intense" on the bike and see how you react. I wouldn't also be too regimented if you simply feel too hungry, abandoning a fast shouldn't really be a big deal - you don't have to suffer to lose weight!

    Thanks, this is interesting and kind of what I was expecting. I’ll give it a go. For me part of the desire to try a fast is for the mental discipline of it also, so it’s important not to wimp out early on. But I take your point re. abandoning it if I feel awful.