Marks Daily Apple
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28 Mar

Dear Mark: Staying Aerobic, Glycogen Depletion, and Sleep-Low for Strength Training?

Staying Aerobic Glycogen Depletion and Sleep-Low for Strength Training FinalFor today’s edition of Dear Mark, I’m answering three reader questions. First, do anaerobic workouts—sprints, lifting, etc.—interfere with your ability to become a fat-burning, aerobic beast, or can you integrate them? Next, in last week’s post I talked a lot about glycogen depletion in the context of the “sleep-low” carb partitioning. How can we actually achieve this without doing the intense intervals the elite triathletes were doing in the study? And finally, does carb-fasting after strength training also work?

Let’s go:

I’ve read Primal Fitness, 21 Day, and now am halfway thru Primal Endurance. You could say I believe in and am an example of the efficacy of your teaching. I’ve been using the 4 days of play, 2 days of LHT, and one day of HIIT as outlined in PF and 21. My confusion comes from the emphasis in Primal Endurance on staying aerobic and how even a short duration of anaerobic can negatively effect body’s ability to function aerobically. I find even when playing Frisbee on a play day I can get my heart rate above my aerobic max after a short sprint, and I definitely get above my max aerobic HR when I do the LHT sessions and HIIT sessions. Im not training for any endurance competitions, just like being really fit so Im thinking the primal endurance model is more focused on those training for super endurance activity but any clarification of the confusion I have re aerobic and anaerobic would be appreciated.

Getting the heart rate up briefly on occasion as you are doing is good and won’t jeopardize your fat-burning pursuits. In the book, we emphasize becoming as efficient as possible at burning fat at the “low end” before you start adding speed if you are seeking the most efficient way to get to racing faster by burning more fat. For that reason, we like picking some workouts where you stay at or below that aerobic zone for as long as possible. So if you are training for a marathon, triathlon or Spartan event, you might put a few more of those dedicated low HR sessions into your routine. But doing harder workouts that rely more on glycogen for energy won’t “ruin” your aerobic base, especially if you’re just a “regular” exerciser looking to get fit, strong, fast, and more attractive. They’ll actually improve your ability to burn fat.

The problems arise when you rely on glycogen all the time and never force your body a chance to rely on fat. So in your case, mixing it up is fine and fun and desirable. I always hammer on this point, and it bears true here: there are no “right” answers here, just choices. In Primal Endurance, we wanted to offer choices that got you to your maximum fat-burning efficiency fastest for those athletes who needed it. People who aren’t hardcore endurance athletes can still learn from and implement the concepts described in the book, but they don’t “have” to follow them to a tee.

“Whatever you do, be sure to really deplete glycogen and wait for 12-16 hours to refill it.”

How do you know when you’ve depleted your glycogen?

Great question. Let’s talk about glycogen depletion.

Glycogen depletion is localized. High rep bicep curls will deplete bicep glycogen. They will not affect glycogen stored in other muscles. Compound movements like squats and deadlifts are better because they’ll deplete multiple sites.

The higher the intensity, the greater the glycogen depletion. Walking depletes very little glycogen. Sprinting depletes the most. Anytime you increase the intensity, you’re increasing the glycogen burn.

Some ideas for glycogen depletion workouts:

Kettlebell complex: 10 swings, 10 clean and presses (5 each arm), 20 reverse lunges (10 each leg), 10 bent over rows (5 each arm). 5 rounds, no rest between movements, minute rest between rounds. You hit pretty much every muscle group. This basic concept can also be done with dumbbells, barbells, and even weight machines.

High rep burpees: Twenty burpees, performed as quickly and cleanly (don’t sacrifice form) as you can. Rest two minutes. Repeat at least 5 times. Burpees are great because they hit arms, chest, legs.

Hill sprints: Run longer sprints with longer rest periods. Throw in some pushups and pullups in between sprints to hit other body parts (because sprinting only depletes the lower body, especially the posterior chain—hamstrings and glutes) if location and available equipment permit. Maybe some bodyweight squats, too, which are pretty quad-dominant.

These 10-minute full body workouts should all work well, too.

One way to tell if you’re depleting glycogen is the difficulty. If a workout is easy, you’re not depleting a ton. If a workout is grueling, you’re depleting it. Strike a balance between hard work, sustainability, and willingness to perform. Short ultra-intense sprints might deplete the most glycogen per second, but how many seconds can you keep it up? 200-meter hill sprints with 5-minute rest periods will blast your lower body glycogen stores, but how willing are you to do that workout on a regular basis?

Another indication of glycogen depletion is if the workout increases glycogen uptake into muscles. If your muscles are taking in more glycogen after a workout, they probably depleted it during the workout. Both sprint and moderate intensity training increase muscle-specific glucose uptake. And strength training definitely increases muscle glucose uptake.

Does this still apply to the more traditional full-body strength workout? I would love to try if so. My carbs have been in the 200-250g range but I’m doing three strength workouts, a sprint workout, and the other days are pretty active playing sports or hiking with my 3 year old. Thanks!

Sure, why not? Full body resistance training and sprinting can certainly deplete glycogen. Maybe not as completely as if you were a triathlete doing long intense intervals every day, but it works. Remember that strength training definitely increases muscle glucose uptake, a strong indicator for prior depletion. And you’re also not eating 6 grams of carbs for every kg of bodyweight like the triathletes in the study were eating, meaning you don’t have as much to deplete. So give it a try. Keep your carb intake constant, just eat them before your workouts rather than after. Try to time it so that you end your carb-free time with a hike or other “low-moderate intensity” activity to really boost fat utilization.

Here’s how it might go:

  1. Eat your carbs.
  2. Sprint or strength train.
  3. Have some protein post-workout, maybe a little whey. No carbs.
  4. Avoid carbs for at least 12 hours. Eat low-carb vegetables, meat, fat. Nothing starchy, nothing sweet.
  5. End your “carb fast” with a hike, walk, or play session. Nothing too strenuous.
  6. Now eat some carbs.

Keep that 200-250 gram carb range going. The implications of the study from last week are that you can eat the same amount of carbs as long as you partition them differently. It’d be cool to see if this works in a standard strength trainee, too. Don’t see why it won’t.

That’s it for today. Any other glycogen-depleting workouts you guys can share?

Thanks for reading, everyone. If any of you have additional tips, input, or questions, leave them down below!

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. Looking for alternative strength training? Try buying a house and diy the reno, haha.
    I love lifting but I haven’t been this sore since I did parkour meetups in college! Up and down ladders, lifting, sanding the ceiling…
    In all seriousness though, when I start burning out on gym or even outdoor fitness work, shaking it up and working towards any new goal (new movement discipline, removing popcorn ceiling, taking up a new sport with a friend or partner, etc) always boosts my motivation and creates new functional movement to play around with and this is certainly the most demanding yet.

    Becky D wrote on March 28th, 2016
    • Yep I’m doing a big reno too.

      No soreness for me but it’s a good work out – also means I don’t have time to eat much and skip meals during the day – lost the minimal body fat I was carrying and muscle and definition has improved.

      Still doing yoga and a bit of gym.

      I eat big at the end of the day and all is good for me.

      Mitch wrote on March 28th, 2016
  2. These were the exact question’s I wanted to ask. Thank you. Assume

    mark N wrote on March 28th, 2016
  3. Nice. Since I don’t have a “glycogen monitor” I like the tips. 😛 Thanks, Mark!!

    Arnold wrote on March 28th, 2016
  4. I love Spartan events. They’re an epic way to deplete glycogen (and just feel epic all around)!!

    JamesL wrote on March 28th, 2016
  5. Mark,

    Really love the site! – recently discovered it and have read several hundred posts.

    I believe your answer to the first reader cleared some confusion I had (“doing harder workouts that rely more on glycogen for energy won’t “ruin” your aerobic base, especially if you’re just a “regular” exerciser looking to get fit, strong, fast, and more attractive. They’ll actually improve your ability to burn fat”), but was hoping you could comment further.

    I am a 56 year old male (quit smoking and began taking care of myself 7 yrs ago after 25 sedentary years of 1 pack/day) with resting heart in the low 50s and bodyfat in the low teens (see ab complex but no definition). Not bad but am trying to up my game.

    Due to time constraints I do one hour 3x weekly – 30 minutes on 4×10 dips, chins, overhead press, and squats. This is followed by 30 minutes of machine cardio, but I go hard (here in the northeast, it is not unusual for snow shoveling or carrying firewood to yield high heart rates for 30-60 minutes so I need to be trained for it), usually 75-85% of max.

    The workouts are done late afternoon where cortisol is generally dimininshed wrt daily cycle. But what am I doing to myself at such high heart rates?

    The duration doesn’t seem that long compared to your training runs when you were competing. Btw wouldn’t Grok have also engaged in such medium duration, high intensity activities periodically (gathering firewood, maybe the actual kill on a hunt, carrying a bison leg back to camp after the hunt, etc), not just heavy lifting and long, slow (walking) and short, fast (sprinting)?


    Dave the Geek

    Dave the Geek wrote on March 28th, 2016
  6. Interesting. I know it should be obvious, but the concept that glycogen levels are localized is illuminating. There’s bicep glycogen levels, quads glycogen levels, etc. When I used to think of glycogen, it was like how I would think of blood sugar: one undifferentiated level distributed evenly throughout the body that either hit bottom or was capped off.

    Jessica wrote on March 28th, 2016
    • There’s a lot in the liver, too. To deplete that locally, drink heavily.
      : )

      Rick wrote on March 28th, 2016
  7. Kettle bells, sprints and burpees are all part of my routine. So I guess I’m doing a good job of depleting that glycogen to access my fat stores. Makes sense, since I’ve been seeing a lot of results. 😀

    Derrick wrote on March 28th, 2016
  8. Hmm, I’d been wondering whether or not it was beneficial to force the body to dig into fat stores every now and then. You’ve helped to answer this for me. It’s almost like the body forgets how to burn fat for energy if it never has to.

    Mitchell wrote on March 28th, 2016
  9. When I try to “sleep low”, I don’t sleep. As I mentioned in the sleep low post, I’ve started experimenting with it. The first night after glyc depletion and no refeed, zing, wide awake in the middle of night. So I aimed to refeed a little bit the second night, to see if that would help my sleep. I forgot to and, zing! wide awake again. So for the past two nights I’ve gone “wake low”, working out in the am or the pm, my choice, and eating ALL my carbs with dinner and snack (none until then). Sleeping normal again!

    When I go low carb long enough I lose all desire to do chores and to work out. That’s how I tell I’m glyc depleted.

    Rick wrote on March 28th, 2016
  10. Strangely, the concept of localized depletion didn’t occur to me either, I kind of just assumed all muscles depleted at the same time. This is a tremendous help.

    So, am I right in thinking that after muscle glycogen is depleted, the liver then sends glycogen to the muscle to top it up, then once the liver glycogen is depleted the body uses stored fat to put more glycogen into the liver to complete the cycle… is this how it works?

    Thanks for all you do Mark!

    Sparrow wrote on March 28th, 2016
  11. Is there a set point or time at which a glycogen gets stored as fat?

    Alexander wrote on March 28th, 2016
  12. I find the C2 rowing machine is my best glycogen depletion tool. 1000 meter warm-up followed by 5 sets of 200 meter all out sprints with 90 second rests and finished with a 1000 meter warm-down.

    Jack Lea Mason wrote on March 28th, 2016
  13. Best glycogen depleting workout I have ever done(and least enjoyable!): burpee ladder. 20, 19, 18,…3,2,1 = 210 total burpees. This is brutal. I try to limit my rest time between sets to 30s, and can usually get done with the full ladder in 19-20 minutes. I don’t think there is a single gram of glycogen left in my body afterwards.

    Shawn wrote on March 29th, 2016
  14. Hi Mark!

    Been a Primal follower for over three years now and am loving life! I have a question regarding the Train High, Sleep Low schedule. I typically work out early in the morning due to work and life schedules, so how do I best implement this plan? I would like to avoid waking up even earlier to eat some sweet potatoes an hour or so before working out, but is it okay to eat some carbs before sleeping the night before? Thanks for all the sage wisdom over the years!

    Jason Shin wrote on March 29th, 2016
  15. Seriously…..Really? Seems like an AWFUL of thinking/planning! I pretty much get a bunch of various exercise, don’t really think about it, and top it off with meat and veggies.Seems easy.

    Marc wrote on March 30th, 2016
  16. Tried to find last weeks study in regards to carbs consumption benighted same but partitioning them. Can someone help me find the study. I pasted where this is mentioned in this post.

    Here’s how it might go:

    Eat your carbs.
    Sprint or strength train.
    Have some protein post-workout, maybe a little whey. No carbs.
    Avoid carbs for at least 12 hours. Eat low-carb vegetables, meat, fat. Nothing starchy, nothing sweet.
    End your “carb fast” with a hike, walk, or play session. Nothing too strenuous.
    Now eat some carbs.
    Keep that 200-250 gram carb range going. The implications of the study from last week are that you can eat the same amount of carbs as long as you partition them differently. It’d be cool to see if this works in a standard strength trainee, too. Don’t see why it won’t.

    Read more:

    David wrote on March 31st, 2016

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