Monday, October 13, 2014

Sodium Bicarbonate (NaHCO3) Increases PGC1-A & Speeds Up Mitochondrial Adaptation - HIIT + Bicarb = Perfect Match

Study suggests, significant increases in mitochondrial builder PGC1-a with HIIT + bicarbonate
If this is not your first visit to the SuppVersity, I am confident you've read about the ergogenic effects of sodium bicarbonate aka baking soda before. If you haven't here is the short version: Sodium bicarbonate will act as a systemic acid buffer during workouts. That's in contrast to beta-alanine which works exclusively in the muscle, but has very similar, in some studies albeit significantly more pronounced and first and foremost acute beneficial effects on exercise performance.

No loading, no waiting, no hoping. You simply wash down 20g of bicarbonate (better 0.3g/kg body weight) before the race of your life and - as long as your tummy can stomach it - see / feel the benefits during the race.
You can learn more about bicarbonate and pH-buffers at the SuppVersity

The Hazards of Acidosis

Build Bigger Legs W/ Bicarbonate

HIIT it Hard W/ NaCHO3

Creatine + BA = Perfect Match

Bicarb Buffers Creatine

Beta Alanine Fails to HIIT Back
In his thesis paper, Michael E. Percival investigated the effects of bicarbonate supplementation on the cellular adaptation process in response to high intensity interval training (HIIT).
"Acute and chronic high-intensity interval exercise is a potent stimulus to influence a number of physiological adaptations with implications for health and athletic performance. [...] Due to the intense nature of this training modality and associated disturbance to muscle pH, which has been implicated in fatigue, it has been hypothesized that augmenting the body’s natural buffering capacity through nutritional means may be a strategy to augment training adaptations. One way of doing this is through the ingestion of NaHCO 3 prior to exercise, which has shown to have ergogenic effects allowing athletes to perform more work with each training session. In addition, greater mitochondrial and performance adaptations are seen when HIIT is preceded by NaHCO3 ingestion even when work is matched (Edge. 2006; Thomas. 2007; Bishop. 2010)."
Percival's goal was now to finally establish what exactly it is that gives bicarbonate the adaptational edge, so to say. To this ends, Michael E. Percival had his subjects, nine active men (22 ± 2 y; 78 ± 13 kg, VO²peak = 48 ± 8 mL/kg/min; mean ± SD) perform the same 10 x 60 s HIIT cycling protocol on two occasions, either with
  • 0.2 g/kg body weight sodium bicarbonate (BICARB) or 
  • an equimolar dose of a placebo, sodium chloride (PLAC),
both ingested in two equally sized doses that were ingested 30 minutes after the breakfast - a means to minimize gastrointestinal distress | and in the study at hand it worked: There was not difference in gastrointestinal complaints between placebo and bicarbonate trial.
Figure 1: Pre vs. post PGC1a and muscular glycogen content (Percival. 2014)
The two trials were separated by 1 week, the subjects had to perform their 10 all out cycling bouts at an intensity of ~263 ± 40 W - more than enough to bring all of them up to the 90%+ heart rate zone. , interspersed by 60 s of recovery. Total work during each trial was identical for a given subject.
A brief reminder of the benefits of bicarbonate: Regulation of hydrogen ions (H + ) or pH within homeostatic concentrations is critical for proper physiological function. The factors contributing to the change in muscle pH seen during intense exercise are numerous and the role of each factor remains hotly debated. However, classically it is believed that a large contributor of H + is through the accumulation of lactate produced from glycolysis. Next to internal buffers, which are exhausted relatively quickly, the shuttling of H + and lactate across the sarcolemma is also believed to play an important role in the maintenance of pH during intense exercise. This is due to the extracellular buffering capacity HCO3 - which is believed to promote the efflux of H + from active muscles ( Hollidge-Horvat. 2000; Bishop. 2004).

Table 1: Overview of the studies Carr et al. reviewed in their meta-analysis (Carr. 2011)
One way to facilitate this process is obviously the provision of exogenous bicarbonate in form of NaHCO3. According to the most recent meta-analysis by Carr et al. (2011), even acute dosing will lead to performance enhancements of 1.7% during short high intensity activities as sprinting. As Percival points out, it does eventually not matter how "sodium bicarbonate imposes its ergogenic effects, the ability to allow athletes to work harder may enhance the exercise stimulus", anyways, and thus contribute to faster / greater size and strength gains. There is yet also accumulating evidence "that NaHCO3 supplementation can improve adaptations independent of greater work output." One of the underlying factors, i.e. the increase in the mitochondrial builder protein PGC-1a has been identified in the study at hand.
Figure 2: Bicarbonate increases mitochondrial respiration specifically during longer-duration exercise (Bishop. 2010) - the study at hand does not just confirm the results of the previous rodent study, it does also provide information about the underlying mechanism that's responsible for the accelerated mitochondrial adaptation w/ sodium bicarbonate.
The latter is important, because otherwise the significant differences in PGC1-a expression (see Figure 1), of which the study at hand indicates that they are the most probably reason for the previously cited significant adapational benefits from bicarbonate supplementation (compare Figure 2), could be a mere function of the training volume.

Based on the data from blood draws and needle biopsies from the vastus lateralis we can now conclude that it is the increase in PGC-1α mRNA, which was increased after 3 h of recovery to a greater extent in BICARB vs. PLAC (~7- vs. 5-fold, p < 0.05) that is responsible for the enhanced adaptations after chronic supplementation.

Speaking of which, as I've previously pointed out, I truly believe that the serial loading protocol, as described by Driller et al. (2012) is the most promising dosing scheme for the long(er)-term use of sodium bicarbonate supplements (read my write-up for more information). Issues with increasing blood pressure or calcium loss as they have been reported for very high sodium chloride intakes in susceptible individuals should, as I repeatedly pointed out, not be an issue (Luft. 1990). In pre- and post-menopausal women on high-protein diets, the addition of small amounts of sodium bicarbonate is in fact an effective way to increase calcium retention and thus any potential negative effects on bone health that may arise as a consequence of protein-induced hypercalciuria (Lutz. 1984).
The increase of PGC1-a is significant, because the signaling protein has previously been shown to exert "IGF-1 Promoting, Myostatin Reducing, Muscle Building Effects" | learn more
Bottom line: While I am pretty sure that many people will still be more attracted by the shiny ads for beta alanine containing supplements, there is little doubt that baking soda is the cheaper and at least acutely more effective buffering supplement.

That being said, the elevated PGC1-a levels in the study at hand add to the existing evidence that bicarb is more than a pre-/intra-workout acid buffer. And while it's still not 100% clear if it is a result of an increased use of intra-muscular glycogen or a consequnce of a reduced acid level during exercise, the increase in PGC1-a of which SuppVersity readers know that it has "IGF-1 Promoting, Myostatin Reducing, Muscle Building Effects" (learn more) make chronic sodium bicarbonate supplementation regimen even more interesting than they've been before | Comment on FB!
References:
  • Bishop, David, et al. "Induced metabolic alkalosis affects muscle metabolism and repeated-sprint ability." Medicine and science in sports and exercise 36.5 (2004): 807-813.
  • Bishop, David J., et al. "Sodium bicarbonate ingestion prior to training improves mitochondrial adaptations in rats." American Journal of Physiology-Endocrinology and Metabolism 299.2 (2010): E225-E233. 
  • Carr, Amelia J., Will G. Hopkins, and Christopher J. Gore. "Effects of acute alkalosis and acidosis on performance." Sports medicine 41.10 (2011): 801-814. 
  • Driller, Matthew W., et al. "The effects of serial and acute NaHCO3 loading in well-trained cyclists." The Journal of Strength & Conditioning Research 26.10 (2012): 2791-2797.
  • Edge, Johann, David Bishop, and Carmel Goodman. "Effects of chronic NaHCO3 ingestion during interval training on changes to muscle buffer capacity, metabolism, and short-term endurance performance." Journal of applied physiology 101.3 (2006): 918-925.
  • Hollidge-Horvat, M. G., et al. "Effect of induced metabolic alkalosis on human skeletal muscle metabolism during exercise." American Journal of Physiology-Endocrinology And Metabolism 278.2 (2000): E316-E329. 
  • Luft, Friedrich C., et al. "Sodium bicarbonate and sodium chloride: effects on blood pressure and electrolyte homeostasis in normal and hypertensive man." Journal of hypertension 8.7 (1990): 663-670. 
  • Lutz, Josephine. "Calcium balance and acid-base status of women as affected by increased protein intake and by sodium bicarbonate ingestion." The American journal of clinical nutrition 39.2 (1984): 281-288.
  • Percival, Michael E. "Sodium bicarbonate ingestion augments the increase in PGC-1α mRNA expression during recovery from intense interval exercise in human skeletal muscle." Diss. McMaster University, 2014.
  • Thomas, Claire, et al. "Effects of high-intensity training on MCT1, MCT4, and NBC expressions in rat skeletal muscles: influence of chronic metabolic alkalosis." American Journal of Physiology-Endocrinology and Metabolism 293.4 (2007): E916-E922.