Low Intensity Cardio and Its Effects on Muscle Loss

[RippedK]

I'll give a little background before I pose my question:

As it is summer, I have been trying to get more cut. I went on the Ultimate Diet 2.0 for two weeks, and had some nice preliminary results. But I am now at home before school starts, and at home I found that I needed to drop the UD2 diet.

Unlike most lifters, I love cardio: low intensity long distance cardio. I like to throw a good magazine down on an elliptical machine, and I typically go at a heart-rate of 120 for an hour. I have been doing this about 4 times per week. In terms of timing, I will do a 45min-1hr lift, drink a whey/dextrose shake, and then hit the elliptical.

My question is whether this long slow distance cardio is eating up my muscle gains? I typically burn about 1000 calories. Basically, from what I have read, I am definitely undermining my bodybuilding gains. Does my post-lift shake help to counteract that loss? To what extent? Is high intensity for like 20 minutes better? I did long distance track in high school and am a former fat kid, so I have a superstition about keeping up the low intensity cardio. But is it counterproductive to my lifting? (I'm 5'10'', 175, ? percent bf). Thanks a lot guys for any input. The last thing I want to do is ruin hard-earned gains because I am doing too much cardio.

[infiniti1982]

if you are worried about muscle loss, split up your cardio/lifting to diff times of the day... say lifting in the mornign and cardio at night (which would only be practically possible if you have a machine at home since no one but a competitive bodybuilder wants to go to the gym twice a day...). this should be more doable once you go back to school tho.

honestly tho, it doesnt sound like you are an ectomorph, so there really isnt a great risk of muscle loss. if you notice strength losses, then you'll know its occuring and you can make changes to your schedule.

the best option in my mind would be to do sprints... say about 10 100m dashes on a track with a one minute rest between each, or 30 second sprints on a machine bike or on an elliptical or a stairmaster or...anything. with a 5 minute warmup and 5 minute cool down that'll only take around 20 minutes. doing that 3x a week (which is all that is necessary) you'd probably notice better results than with your current cardio schedule. you can do more intervals per session once that stops working. not sure if youve ever done sprints like this, but to make sure you are doing it right, if you don't feel like dying by the end you aren't going hard enough (the downside to HIIT).

as a side note, i highly recommend dropping dextrose. im sure pretty sure everyone will disagree with me here (on this board, i mean), but use oats in your PWO shake instead. i dont care what the studies say, because this is what I have personally noticed and why people other than myself advocate this practice: during bulking periods, my strength/size increases are right on par with a malto/dex mix PWO and there is less fat gain; during a cutting phase, i make faster progress (and my strength on all exercises maintains and very often increases). try it for a week and see if you like it. i wasn't convinced at first and didn't even want to "sacrifice" a week of gains to try it, but once i did I never went back (and i now have about 10lbs of dextrose and 7lbs of maltodextrin wasting away in my cupboard).

[infiniti1982]

i take that back, i do care what the studies say...




Jentjens R, Jeukendrup A.

Human Performance Laboratory, School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, Birmingham, UK.

The pattern of muscle glycogen synthesis following glycogen-depleting exercise occurs in two phases. Initially, there is a period of rapid synthesis of muscle glycogen that does not require the presence of insulin and lasts about 30-60 minutes. This rapid phase of muscle glycogen synthesis is characterised by an exercise-induced translocation of glucose transporter carrier protein-4 to the cell surface, leading to an increased permeability of the muscle membrane to glucose. Following this rapid phase of glycogen synthesis, muscle glycogen synthesis occurs at a much slower rate and this phase can last for several hours. Both muscle contraction and insulin have been shown to increase the activity of glycogen synthase, the rate-limiting enzyme in glycogen synthesis. Furthermore, it has been shown that muscle glycogen concentration is a potent regulator of glycogen synthase. Low muscle glycogen concentrations following exercise are associated with an increased rate of glucose transport and an increased capacity to convert glucose into glycogen.The highest muscle glycogen synthesis rates have been reported when large amounts of carbohydrate (1.0-1.85 g/kg/h) are consumed immediately post-exercise and at 15-60 minute intervals thereafter, for up to 5 hours post-exercise. When carbohydrate ingestion is delayed by several hours, this may lead to ~50% lower rates of muscle glycogen synthesis. The addition of certain amino acids and/or proteins to a carbohydrate supplement can increase muscle glycogen synthesis rates, most probably because of an enhanced insulin response. However, when carbohydrate intake is high (> or =1.2 g/kg/h) and provided at regular intervals, a further increase in insulin concentrations by additional supplementation of protein and/or amino acids does not further increase the rate of muscle glycogen synthesis. Thus, when carbohydrate intake is insufficient (<1.2 g/kg/h), the addition of certain amino acids and/or proteins may be beneficial for muscle glycogen synthesis. Furthermore, ingestion of insulinotropic protein and/or amino acid mixtures might stimulate post-exercise net muscle protein anabolism. Suggestions have been made that carbohydrate availability is the main limiting factor for glycogen synthesis. A large part of the ingested glucose that enters the bloodstream appears to be extracted by tissues other than the exercise muscle (i.e. liver, other muscle groups or fat tissue) and may therefore limit the amount of glucose available to maximise muscle glycogen synthesis rates. Furthermore, intestinal glucose absorption may also be a rate-limiting factor for muscle glycogen synthesis when large quantities (>1 g/min) of glucose are ingested following exercise.





Physiological hyperinsulinemia stimulates p70(S6k) phosphorylation in human skeletal muscle.

Hillier T, Long W, Jahn L, Wei L, Barrett EJ.

Department of Internal Medicine, Division of Endocrinology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA.

Using tracer methods, insulin stimulates muscle protein synthesis in vitro, an effect not seen in vivo with physiological insulin concentrations in adult animals or humans. To examine the action of physiological hyperinsulinemia on protein synthesis using a tracer-independent method in vivo and identify possible explanations for this discrepancy, we measured the phosphorylation of ribosomal protein S6 kinase (P70(S6k)) and eIF4E-binding protein (eIF4E-BP1), two key proteins that regulate messenger ribonucleic acid translation and protein synthesis. Postabsorptive healthy adults received either a 2-h insulin infusion (1 mU/min.kg; euglycemic insulin clamp; n = 6) or a 2-h saline infusion (n = 5). Vastus lateralis muscle was biopsied at baseline and at the end of the infusion period. Phosphorylation of P70(S6k) and eIF4E-BP1 was quantified on Western blots after SDS-PAGE. Physiological increments in plasma insulin (42 +/- 13 to 366 +/- 36 pmol/L; P: = 0.0002) significantly increased p70(S6k) (P: < 0.01), but did not affect eIF4E-BP1 phosphorylation in muscle. Plasma insulin declined slightly during saline infusion (P: = 0.04), and there was no change in the phosphorylation of either p70(S6k) or eIF4E-BP1. These findings indicate an important role of physiological hyperinsulinemia in the regulation of p70(S6k) in human muscle. This finding is consistent with a potential role for insulin in regulating the synthesis of that subset of proteins involved in ribosomal function. The failure to enhance the phosphorylation of eIF4E-BP1 may in part explain the lack of a stimulatory effect of physiological hyperinsulinemia on bulk protein synthesis in skeletal muscle in vivo.

[Shibby]

Maybe we are reading this wrong, but I don't think that study backs up your statement. It talks about carbohydrates and it's use in glycogen synthisis. Dextrose and Maltodextrin are forms of simple carbs with a quick absorbtion rate, which stimulate glycongen synthisis.

[infiniti1982]

Sorry I didn't include any informational guidance along with those two studies. Here is what I mean:

The trend of using an extremely high GI CHO after workout is to spike insulin levels and maximize levels of glycogen (and then protein) synthesis.

However, as the first study shows, this period of muscle glycogen synthesis occurs regardless of any CHO consumed during the post-exercise period. The physiological goals of those drinking high GI shakes PWO are fulfilled without their method (their high GI shake).

Thus, since the scenario of muscle glycogen synthesis occurs regardless of CHO, any CHO will be sufficient PWO. Low GI is clearly the perfect choice (as it at all other times of the day).

The source of CHO determines two things: body composition (who cares about that though, right?) and insulin resistance. As we all know, high GI carbs are much more likely to be stored as fat, and that's why we avoid them during most parts of the day. High GI carbs are unnecessary PWO and no better for us or excusable than they would be at any other time of the day.

The second study shows that high levels of insulin and glycogen reloading (what a high GI meal pwo would cause) are not the cause of high levels of protein synthesis.


i'm bad at explaining things, so let me know if i've illustrated the significance of those two studies sufficiently.

[infiniti1982]

One thing to note is that those of us with very fast metabolisms can probably handle high GI carbs better than those with slower metabolisms (in terms of their effects on body comp.) I have a slower metabolism, so when I cut out the high PWO meal, I noticed a big difference. For someone with a fast metabolism, they might not notice a thing because they're not putting on fat when they bulk anyways and when they cut, they can do so without trouble.

I'm recommending low gi as a change to this guy because it sounds like he is not one of those endowed with a fast metabolism. it will help his cutting goals to a significant degree.

[RippedK]

Thanks for the info glowalla. I'm going to suck it up and try to change from low intensity to HIIT or other such interval training. It's harder, but it actually brings gain.

Also, I'll definitely try the oats. As an endo, I never liked the idea of drinking sugar.

[RippedK]

Also, about how many grams of carbs of oats do you suggest? Like 30g?

[RippedK]

Just got back from the gym. Did an HIIT workout and it kicked my ass. I got a crazy runner's high though; haven't had one of those in a while.

Heart rate got up to 185. Is that a good place to be?

Gonna be sore tomorrow....

[infiniti1982]

ya hiit will make you more sore than squats/deadlifts at first... 185 sounds perfect for your heart rate. if you are doing this on a treadmill, i'd recommend you change that. reason being is that you can't sprint on a treadmill. it controls your speed (generally allowing only 12mph as a max) and also takes a bit of time to adjust the belt to the increased speed at the beginning of each interval. The standing bike is my favorite for HIIT in the gym, followed by the elliptical. They both allow you to go as fast as you can and don't present any delays when your speed changes. just as a guideline, when i do HIIT on the bike, i usually set the resistance at around 8 (of 20) and i get my rpm to around 150 during my sprint. however fast (or slow) your max speed is is fine however, as long as you are going at your max.

one more thing on HIIT. its a huge fucking bitch, but believe it or not, there is a supplement you can take that actually works and will make the experience much easier. its called citrulline malate and you can buy it as a bulk powder at a bunch of places (bulknutrition.com being one of them) for relatively cheap. its kinda like the aerobic brother of creatine: as creatine allows for more anaerobic endurance and output(like with weight lifting...), citrulline malate will increase your aerobic output (like with the type of sprinting you are doing in your HIIT). it does work unlike 99% of all supplements and is relatively new to the market. Take 3g before your workout and 3g after. you will notice changes after one week of consumption (though possible sooner).

[Citrulline/malate promotes aerobic energy production in human exercising muscle.

Bendahan D, Mattei JP, Ghattas B, Confort-Gouny S, Le Guern ME, Cozzone PJ.

Centre de Resonance Magnetique Biologique et Medicale, UMR CNRS 6612, Faculte de Medecine de la Timone, 27 Boulevard Jean Moulin, 13005 Marseille, France.

BACKGROUND: Previous studies have shown an antiasthenic effect of citrulline/malate (CM) but the mechanism of action at the muscular level remains unknown. OBJECTIVE: To investigate the effects of CM supplementation on muscle energetics. METHODS: Eighteen men complaining of fatigue but with no documented disease were included in the study. A rest-exercise (finger flexions)-recovery protocol was performed twice before (D-7 and D0), three times during (D3, D8, D15), and once after (D22) 15 days of oral supplementation with 6 g/day CM. Metabolism of the flexor digitorum superficialis was analysed by (31)P magnetic resonance spectroscopy at 4.7 T. RESULTS: Metabolic variables measured twice before CM ingestion showed no differences, indicating good reproducibility of measurements and no learning effect from repeating the exercise protocol. CM ingestion resulted in a significant reduction in the sensation of fatigue, a 34% increase in the rate of oxidative ATP production during exercise, and a 20% increase in the rate of phosphocreatine recovery after exercise, indicating a larger contribution of oxidative ATP synthesis to energy production. Considering subjects individually and variables characterising aerobic function, extrema were measured after either eight or 15 days of treatment, indicating chronological heterogeneity of treatment induced changes. One way analysis of variance confirmed improved aerobic function, which may be the result of an enhanced malate supply activating ATP production from the tricarboxylic acid cycle through anaplerotic reactions. CONCLUSION: The changes in muscle metabolism produced by CM treatment indicate that CM may promote aerobic energy production.]

as far as how much oats, that really depends on how many carbs you are taking in during the whole day. 30g is ok if your carb intake is really low for the day, like around 150g or something. Personally, I like to put an unproportionately large amount of carbs into my PWO shake. So if I'm eating 200g carbs in a day on a cut, I'd use 60g or a little over one cup of oatmeal. Also, just to make things easier, you don't have to cook the oats PWO. I usually make a protein shake in the blender with ice, and then when that's blended I'll throw in the oats and mix it in at a low setting for a couple of seconds. That makes it so that the oats get mixed up evenly in the shake, but they dont get pulverized... though grinding up oats doesn't affect their GI nearly as much as you'd think.

[RippedK]

Glowalla - Citrulline malate sounds like the bomb. Is it as harmless as creatine? I did some research and they have been giving it to old people in europe for about two decades, and it seems safe as apple pie! I wonder why the supp industry hasn't given it a huge push.

[wheyman]

Yellowjacket would be a great person to ask about this supplement