Carbohydrate Timing Boosts Training Effect: Cut Out Carbs After PM Glycogen Depleting HIT Workout ⇨ "Sleep Low" to Make Game-Changing Performance Gains in Only 3 Weeks

Carbohydrate Timing Boosts Training Effect: Cut Out Carbs After PM Glycogen Depleting HIT Workout ⇨ "Sleep Low" to Make Game-Changing Performance Gains in Only 3 Weeks

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You are no triathlete or coach? That doesn't mean that this study isn't of interest for you. The figurative "extra wind" this training strategy can give you is relevant for almost every athlete.

In a recent study, scientists from the French National Institute of Sport investigated the effect of a chronic dietary periodization strategy in a group of twenty-one highly-trained male triathletes. Previous studies, in which "train-low" strategies, during which athletes are deliberately carbohydrate restricted over certain periods of their training cycle, have reported robust a up-regulation of selected markers of training adaptation (increased whole body fat oxidation, increased activities of oxidative enzymes) compared to training with normal glycogen stores and high CHO availability, however, the subjects experienced at best disappointing performance increases.

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Scientists have long speculated that the disconnect between the benefits "training low" offers on the level of cellular / mitochondrial adaptation, on the one hand, and the real-world performance increases, on the other hand, could be a consequence of the necessarily reduced high intensity training intensity during the low-carb phases (Yeo. 2008; Hulston. 2010). If we simply assume that this hypothesis is correct, the solution to the problem should be obvious: Train low when carbohydrates are not necessary and use them, whenever they promote maximal performance.

Marquet et al. implemented this principle in a way I tried to illustrated in Figure 1. More specifically, they tried to maximize the subjects' performance during PM high-intensity training (HIT) by providing copious amounts of carbohydrates before the session and restricted the carbohydrate intake to close to zero after this glycogen-depleting workout.To test the efficacy of this protocol, the scientists used a 2x3 week study design in which the first 3 weeks were used to standardize the volunteers training regimen (10-15 h·wk- 1 : 40% running, 35% cycling, 25% swimming), assess subjects' compliance to the study demands and ensure they all attained similar baseline fitness measures before study commencement.

Figure 1: Overview of important aspects of the dietary / supplemental aspects of the study.

During the decisive second 3-week phase, the subjects were instructed to follow identical diets (by prescribing exact menus, the scientists achieved a high degree of standardization) in combination with either the previously described "sleep low" carbohydrate intake strategy or their usual carbohydrate intake patterns. Unlike the diet / supplementation regimen, the training program the subjects followed was identical for all of them - it ...

Figure 2: Sample weekly protocol for training and CHO intake (g/kg) to achieve different CHO avail. around training (Marquet. 2016)

"consisted of six sessions over four consecutive days, including high intensity training (HIT) sessions in the afternoon and low intensity training (LIT) sessions the next morning. [...] LIT sessions consisted in 60 min cycling at 65% MAP (218.8 ± 20.4 W - 95% CI: 227.5 and 210.7), while HIT sessions consisted alternatively in 8 x 5 min cycling at 85% MAP (286 ± 26.7 W- 95% CI: 297.5 and 274.7) or 6x5 min running at their individual 10 km intensity with 1 min recovery between sets (37). [...] One LIT session per day was prescribed for the other days of the week for a total training volume of 10-15 h" (Marquet. 2016).

All subjects used their own training equipment to record their activity, the duration and intensity of exercise and heart rate. In conjunction with the volunteers' perceived exertion records, as well as VO2max tests, maximal and submaximal performance tests and the results of a simulation of the final leg of a triathlon race, the scientists got a pretty comprehensive set of data.

The effect of "training low" largely depends on the master regulator of mitochondrial adaptation PGC-1a. The latter is activated not just by the contraction induced calcium flux and exercise stress, but also by a lack of glycogen and increased levels of the (low) energy sensing protein AMPK.

How does "training low" work? By deliberately restricting the carbohydrate intake during certain phases of your training you will be able to train in a glyocogen-depleted state and thus with clearly suboptimal fuel availability. The lack of readily available glucose that can be derived from the glycogen stores in your muscle, whenever necessary, exerts profound effects on your overall resting fuel metabolism and patterns of fuel utilization during exercise and triggers acute regulatory processes underlying enzyme and gene expression, as well as cell signaling (signaling proteins, gene expression, transcription rate of several genes, enzymes activity) which regulate the adaptive response to exercise. The results are an increased capacity to oxidize fat, a reduced reliance on glucose as a preferred substrate, etc.

Data that tells us that the authors' hypothesis that they could get the benefits of training low while avoiding the negative sides by "sleeping low" was accurate:

• 

  Figure 3: Make no mistake about it! The total amount of CHO the subjects consumed was identical it was just timed differently. No difference existed for any of the other macronutrients, either (Marquet. 2016).

  There was a significant improvement in delta efficiency during submaximal cycling , i.e. the power output per calorie, a very important measure for endurance athletes, for the "sleep low" compared to the control group (CON: +1.4 ± 9.3 %, SL: +11 ± 15 %, P<0.05).
• A similarly pronounced, albeit due to inter-individual differences, which loom large in studies with relatively few participants, only borderline significant (P = 0.06) beneficial effect was observed during the supra-maximal cycling to exhaustion trial at 150% of peak aerobic power, where the control group saw improve-ments of only 1.63 ± 12.4 %, while the "sleep low" group improved by 12.5 ± 19.0 %.
• The "sleep low" protocol also triggered significantly higher (P < 0.05) improvements in 10k running performance, where the meager -0.10 ± 2.03 % increase in the control group was topped by a -2.9 ± 2.15 % performance increase in the "sleep low" group.

In the "sleep low" group, even the effects on the body composition were significantly more pronounced compared to the control group. To be precise, the subjects who "slept low" burned a whopping 8.7 ± 7.4 % body fat literally overnight, while the control group lost a likewise measurable, but significantly lower and overall non-significant -2.6 ± 7.4% of their body fat - don't be mislead by the size of the bars in Figure 4; the fat mass is on the right axis which starts at 8kg and ends at 10kg. So there was no significant inter-group difference at baseline. No significant inter-group differences were observed for the changes in lean and total mass, either.

Figure 4: Even if you're not training for performance, the improvements in body composition, or more specifically the significant reduction in body fat without sign. changes in lean or total mass, may be of interest for you | total and lean mass on the left axis, fat mass on the right axis; all values in kilograms; sign. changes in % above bars (Marquet. 2016).

Against that background, it is by no means an exaggeration to say that even in the short-term (and that's what I consider particularly impressive here) the "periodization of dietary CHO availability around selected training sessions" can promote "significant improvements" in several highly relevant performance marker of trained athletes" (Marquet. 2016).

8x Increase in "Mitochondria Building" Protein PGC1-Alpha W/ Medium Inten-sity Exercise in Glycogen Depleted Elite(!) Cyclists | Learn more

Drop the carbs pre-bed! No, that's not because carbohydrates in the evening would make you fat. As a SuppVersity reader you know that this is bogus (learn more). The reason why you should consider dropping carbs in the PM (or rather after intense workouts) is their "anti-adaptive" effect - an effect that occurs in response to their ability to replenish your glycogen-stores and thus shut down the "we need to adapt to use more fat" signal to your mitochondria...

Ok, that's not exactly the most scientific explanation (see red box for more), but it is one that highlights one of the most important and yet commonly overlooked principles of physiological adaptations: they occur in response to a need.

If you always provide more than enough carbohydrates, there's no need to increase your ability to use fat as a fuel. If, on the other hand, you (A) fuel yourself with carbs when your body really needs them (during HIT training) to perform at the crucial i + 1 level that will trigger an adaptive response at high intensities, and (B) cut yourself off of a readily available carbohydrate supply when you don't need them (during sleep and low intensity exercise) you maximize the adaptive response to both HIT and LIT (low intensity training) and boost your overall training results | Comment!

References:

• Hulston, Carl J., et al. "Training with low muscle glycogen enhances fat metabolism in well-trained cyclists." Medicine and science in sports and exercise 42 (2010): 2046-55.
• Marquet, et al. "Enhanced Endurance Performance by Periodization of CHO Intake: “Sleep Low” Strategy." Medicine & Science in Sports & Exercise (2015): Publish Ahead of Print.
• Yeo, Wee Kian, et al. "Skeletal muscle adaptation and performance responses to once a day versus twice every second day endurance training regimens." Journal of Applied Physiology 105.5 (2008): 1462-1470.

Post-Workout Coffee Boosts Glycogen Repletion by Up to 30% and May Even Have Sign. Glucose Partitioning Effects

Post-Workout Coffee Boosts Glycogen Repletion by Up to 30% and May Even Have Sign. Glucose Partitioning Effects

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Yes, I do suggest that it may be beneficial to drink these two and another two cups of coffee w/ lots of sugar after your workout - if you are an athlete, at least.

A delicious and refreshing pre-workout coffee or just plain caffeine from pre-workouts are probably on the supplement list of most of the SuppVersity readers. Whether the same is the case for a post-workout coffee, let alone caffeine tablets, though, is questionable. Just as questionable, as the common belief that you better stay away from coffee at any time after your workouts, by the way.

If you look at the existing literature, the effects of post-workout caffeine ingestion are not exactly an intensely researched area. And still, the evidence does more or less strongly support the notion that a post-workout coffee could be as beneficial as its pre-workout analog - in a different area.

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Initial evidence that the post-workout ingestion of caffeine may have beneficial effects on post-workout gylcogen resynthesis and thus an important part of the recovery process comes from a 2004 study by Battram et al. (2004). Back in the day, Battram assumed - just like you probably did - that the ingestion of caffeine after prolonged exercise would impede the resynthesis of proglycogen and macroglycogen carbohydrate supplementation in humans.

Figure 1: Total glycogen [proglycogen (PG) macroglycogen (MG)] glycogen concentrations during 5 h of recovery in the placebo trial (A) and caffeine trial (B | Battram. 2004).

As you can easily see if you compare the data in Figure 1 (A) for the placebo trial with the data in Figure 1 (B), which was generated in the trial in which the healthy young men who participated in Battram's study received a whopping dose of 6mg/kg of caffeine, there is no ill effect on post-workout gylcogen resynthesis even with high dose caffeine supplementation.

"In conclusion, Caf ingestion does not impede the resynthesis of PG or MG after an extensive depletion of muscle glycogen and with the provision of exogenous dietary carbohydrate" (Battram. 2004).

As surprising as this may be in view of the inhibitory effect of caffeine on full-body glucose uptake (in Battram's study there was also a significantly higher blood glucose concentration in the caffeine
trial), Battram's results are still no outliers. Rather than that, a follow up study by Pedderson et al. found that, in trained subjects, coingestion of large amounts of Caff (8 mg/kg BM) with CHO has an additive effect on rates of postexercise muscle glycogen accumulation compared with consumption of CHO alone" (Pedderson. 2008).

Even though Beelen's study does not support the the superior effect of caffeine on muscle gylcogen, it does at least show that the effect (if it occurs) would probably be identical for fast- and slow-twitch muscles and thus similarly beneficial for strength and endurance athletes (Beelen. 2011).

So, there is no doubt that this works? Well, as usual, there is doubt. Another 2011 study by Beelen et al. did not find the same increases in glycogen resynthesis. It is well possible, though that this was due to either the fact that they pumped their subjects up with even higher amounts of carbs, though (1mg/kg/h in Pedderson vs. 1.2mg/kg/h in Beelen) and lower amounts of caffeine (15% less). In view of the fact that the exercise protocol used in the study only halved the glyocogen levels of the subjects, while it was reduced by >75% in the Pedderson study, the lack of effect may also be a result of the lack of full glycogen depletion in Beelen's study (unfortunately, the authors don't provide their values only in arbitrary units - that's why I can't tell you with certainty to which degree this may have influenced the results).

In that, it is important to point out that the increased glycogen resynthesis in Pedderson's randomized, double-blind crossover study, in which the young well-trained subjects performed intermittent exhaustive cycling and then consumed a low-CHO meal before they rode until volitional fatigue and consumed either

• CHO [4 g/kg body mass (BM)] alone or
• CHO [4 g/kg body mass (BM)] with Caff (8 mg/kg BM)

at the beginning of the 4 h of passive recovery phase, did not occur at the expense of the restoration of the high energy substrates ATP and PCr (see Figure 2) - since the latter two are especially relevant for people who lift weight, sprint and do other high intensity stuff, there's no reason to believe that the caffeine + sugar post-load was something only endurance athletes could use.

Figure 2: High dose caffeine (8mg/kg) increases glycogen resynthesis after exhausting workouts without having ill effects on the resynthesis of ATP and PCr (Pedderson. 2008).

Apropos "using" this strategy: Another three years later, Taylor et al. (2011) expanded on the results of Battram (2004) and Pedderson (2008) in a study in which they went beyond testing the mere amount of glycogen that was transported into the muscle and evaluated its effect on the subjects' performance in a post-recovery high-intensity interval-running capacity test.

Figure 3: Exercise capacity during the Loughborough Intermittent Shuttle Test for the carbohydrate (CHO), CHO plus caffeine (CHO+CAFF), and water (WAT) trials. Lines represent individual subject responses (Taylor. 2011).

As you can easily see in Figure 3, the HIIT advantage, which was tested 4h after the glycogen-depleting exercise protocol and the ingestion of 1.2g/kg carbohydrate +/- 8mg/kg caffeine via an Intermittent Shuttle Test (LIST) to volitional exhaustion, was about as pronounced as the glycogen-advantage Pedderson et al. observed three years before (albeit with some inter-individual differences).

Why would you say caffeine may have a partitioning effect? The answer is easy: While fat cells need insulin to transform and store significant amounts of glucose, muscle cells don't - specifically after workouts the increase in GLUT-4 receptor expression and glucose uptake occurs largely without requiring insulin as a trigger. Now, caffeine's ill effects on blood glucose are due to its ability to block the insulin signalling via beta-adrenergic activity (Thong. 2002). It should thus reduce the glucose uptake by the fat cells while decreasing the rate, but not the total amount of glucose that is taken up and stored by the muscle... speaking of rate and total amount: This hypothesis is fully in line with the initially cited study by Battram et al. who observed just that: a decreased rate, but identical total increase in muscle glycogen.

So why haven't we been taking our post-workout caffeine for years, now? Well, I guess the reason is that it is not sure how the effects of caffeine on the sympathetic nervous may effect other factors of the recovery process. In view of the fact the central nervous system will be "on fire" after any workout, though, it is questionable whether adding in 400-800mg caffeine will actually affect its recovery.

A better reason for not (yet) subscribing to the post-workout caffeine binges would thus be that (a) few of us actually need to refill their glycogen stores in 4-6h after a workout and that we (b) have no real clue what the mechanism is. If it was actually - as some of the data would suggest - a selective inhibition of fat cell glucose uptake (see box on the right), even those of us who don't have to restore their glycogen stores as fast as possible may see beneficial effects on body composition. If, on the other hand, it works by stimulating the intestinal absorption of glucose, only (cf. Van Nieuwenhoven. 2000), the real world implications for the average trainee would be significantly less pronounced | Comment on Facebook!

References:

• Battram, Danielle S., et al. "Caffeine ingestion does not impede the resynthesis of proglycogen and macroglycogen after prolonged exercise and carbohydrate supplementation in humans." Journal of Applied Physiology 96.3 (2004): 943-950.
• Beelen, Milou, et al. "Impact of caffeine and protein on postexercise muscle glycogen synthesis." Med Sci Sports Exerc 44.4 (2012): 692-700.
• Pedersen, David J., et al. "High rates of muscle glycogen resynthesis after exhaustive exercise when carbohydrate is coingested with caffeine." Journal of Applied Physiology 105.1 (2008): 7-13.
• Taylor, Conor, et al. "The effect of adding caffeine to postexercise carbohydrate feeding on subsequent high-intensity interval-running capacity compared with carbohydrate alone." International Journal of Sport Nutrition andExercise Metabolism 21.5 (2011): 410.
• Thong, Farah SL, and Terry E. Graham. "Caffeine-induced impairment of glucose tolerance is abolished by β-adrenergic receptor blockade in humans." Journal of applied physiology 92.6 (2002): 2347-2352.
• Van Nieuwenhoven, M. A., R-JM Brummer, and F. Brouns. "Gastrointestinal function during exercise: comparison of water, sports drink, and sports drink with caffeine." Journal of applied physiology 89.3 (2000): 1079-1085.