|You will be pleased to hear that the 30% increase in serum bicarbonate observed in the loading study was achieved in the absence of gastrointestinal distress in ALL subjects.|
Sunday, September 22, 2019, was ‘bicarbonate day’ in the SuppVersity Facebook News: What does that even mean? Well, the daily ‘classics’, i.e. links to archived SuppVersity articles, were all about the polyatomic anion HCO3. Today’s article brings NaHCO3, aka baking soda, back into the limelight – as a post-workout re-alkalizer that can be used with a newly developed and proven bicarbonate loading protocol that will help you avoid diarrhea and work even more efficiently than the classic 0.3-0.5g/kg protocols 😮
IMHO, it’s however the latter study by Amerigo Rossi et al. (2019) that warrants the previously used 😮-emoji as it could allow a large group of people whose digestive tracts have hitherto prevented them from using the #4 ergogenic on the SuppVersity short-list of “supplements that work” (#1 whey, #2 creatine, #3 caffeine, …).
Amerigo Rossi and his colleagues were obviously well-aware of both, (a) the “explosive” problems the ingestion of large amounts of bicarbonate can have on the largely undigested content of your intestines, and (b) the ergogenic prowess of the salty H+ buffer. Accordingly, …
“the purpose of [their] study was to determine whether a modified sodium bicarbonate (SB) ingestion protocol would elevate serum bicarbonate concentration more than previous methods without causing gastrointestinal distress” (Amerigo Rossi 2019).
To this ends, the US researchers recruited seven (5 men, 2 women) elite middle-distance runners who, in a random order, ingested either placebo (calcium carbonate which has repeatedly been used successfully in previous sodium bicarbonate research), modified SB (600 mg·kg− 1 over 19.5 h), or acute SB (300 mg·kg− 1) in opaque gelatin capsules
Since the same caps were used in all groups, it can be excluded that they significantly contributed to the benefits of serial loading that were observed in the study under review.
In order to maintain the double-blind design of the study, the first three doses of the Acute SB protocol contained the placebo, and only the last dose contained 300 mg/kg of SB… Table 1 shows the exact ingestion pattern:
To assess the effects of sodium bicarbonate (#SB) and the way it was administered, baseline and post-ingestion blood samples were analyzed for bicarbonate, pH, sodium, hematocrit, and lactate; the corresponding data was then analyzed by repeated-measures ANOVA (2 time points × 3 conditions) to determine differences in serum bicarbonate, lactate, sodium, blood pH, and hematocrit.
No, athletic performance wasn’t measured directly in the loading trial, but one can assume…
So, while the study unfortunately lacks an exercise part, the subjects’ individual gastrointestinal distress was assessed – via self-report on a Likert scale of 1–10. Simple (condition) and repeated (time) within-participant contrasts were used to determine the location of any statistically significant main and interaction effects (p ≤ 0.05).
|Correcting a diet-induced low-grade metabolic acidosis with K-bicarbonate reduces the nitrogen loss of 750mg – 1000mg per day (per 60kg BW) in postmenopausal women (Frassetto. 1997) – previous studies suggest identical benefits for sodium bicarb.|
Special service for the healthy skeptics who are just about to post in the comments that ‘you cannot change your body’s pH, anyway’: “Previous physiologic studies in normal adults have shown that differences in dietary acid affect extracellular pH and serum bicarbonate (Sebastian 1994, Kurtz 1983). […] Our results extend these findings to indicate that dietary acid plays a role in determining acid–base status on a population-wide level and that this effect is most pronounced among older persons” (my emphasis in Amodu 2013).
It’s correct that your kidneys (and lungs) will always return your pH to the normal range (unless you’re too old and/or your organs are malfunctioning), but this doesn’t mean that putative benefits of not making them work over-time are unscientific.
Speaking of distress the latter was not the reason that 3 of the initial N=10 subjects dropped out of the study. Two of the very fit subjects (BF 70 ml/kg/min sustained injuries during private training sessions and one withdrew for undisclosed private reasons (pretty much the dropout you, unfortunately, have to expect in scientific studies).
Significant alkalizing effects… 🤔 but there’s something missing, isn’t it?
As hypothesized the scientists twist on serial loading did “significantly elevate serum bicarbonate concentration and produce less GI distress than typical acute SB ingestion”. More specifically,…
“There was a significant interaction effect between condition and time (F = 9.52, p < 0.01) for serum bicarbonate concentration (Fig. 1). Although the placebo trials induced a small (2.7 mmol·L− 1) but significant (p < 0.01) increase in serum bicarbonate concentration, contrasts revealed that there were significantly greater increases in serum bicarbonate concentration for the AcuteSB (5.8 mmol·L− 1, p < 0.01) and ModSB (7.6 mmol·L− 1, p < 0.01) conditions compared to the placebo from Baseline to post-ingestion. Furthermore, post-ingestion serum bicarbonate concentration was significantly higher (p = 0.05) for the ModSB condition (34.7 ± 2.2 mmol·L− 1) than the AcuteSB condition (33.5 ± 2.0 mmol·L− 1)” (my emphasis in Amerigo Rossi 2019)
Cool, ha? Well, yes and no, ’cause measuring the bicarbonate level alone relies on the previously observed correlation of serum bicarbonate levels and the ergogenic benefits – a link that has been observed in studies most of which have used acute administration protocols.
|Figure 1: Serum bicarbonate concentration at baseline, post-ingestion. * Significantly different from placebo. † Significantly different from Acute SB (Amerigo Rossi 2019)).|
The observed improvements in blood bicarbonate levels are thus likely to translate to performance increases (during high-intensity exercise) but only a follow-up study will show if those benefits are as impressive as the changes in bicarbonate you see plotted in Figure 1.
If the bicarbonate levels accurately predict the performance benefits, the serial loading protocol should translate into performance benefits of up to 30% even compared to the acute protocol!
Overall, it would seem unrealistic to expect that the >30% difference in bicarbonate levels observed in the study at hand will produce similarly large performance benefits in terms of total time to exhaustion or time trial times. I’d rather expect the dose-response curve for serum bicarbonate vs. performance to be logarithmic. This means that, at low bicarbonate levels, any increase in buffering capacity that comes with bicarbonate supplementation is going to yield much greater performance benefits than the same increase from already elevated levels.
But let’s leave that for future studies to investigate and turn to the other study I’ve mentioned in the introduction.
Study 2, suggests that the repeated provision of bicarbonate and fast restoration of the acid-base balance after workouts allows for greater performance on subsequent high-intensity workouts.
If you belong to the aforementioned group of acid-base skeptics (see red box), you’ll probably be “offended” (as everybody is these days) by the results of Lewis A. For Gough’s paper, the researchers from the UK and South Africa tested the effects of either 0.3 g/kg body mass NaHCO3, or 0.1 g/kg body mass sodium chloride (PLA) in seven elite male professional boxers who performed an initial bout of exhaustive exercise comprising of a boxing specific high-intensity interval running (HIIR) protocol, followed by a high-intensity run to volitional exhaustion (TLIM1), before a 75 min passive recovery period that was kickstarted with the “salt fix” being ingested 10 minutes into the recovery (the delay may be important for tolerability issues, hence I mention it explicitly).
|Figure 2: The rapid increase in pH after the workout (inset) supposedly facilitated the significant increase in time to exhaustion in the high-intensity run to volitional exhaustion (Gough 2018).|
After the 1 1/4h rest period, the boxers underwent a standardized sports-specific high-intensity exercise test involving a boxing specific punch combination protocol, followed by a second high-intensity run to volitional exhaustion (TLIM2).
Unlike in the 1st test, TLIM1 (before supplementation), where the scientists observed no inter-group differences, Gough et al. detected significant differences in performance from TLIM1 to TLIM2 with NaHCO3 allowing the athletes to run a whopping ~125% longer ‘on bicarbonate’ than on the placebo supplement (+164 ± 90 vs. +73 ± 78 sec; p = 0.02, CI = 45.1, 428.8, g = 1.0) 😍.
|Figure 3: The acute provision of high amounts of NaHCO3 in the Ghough study produced only short-lived GI discomfort wich could likely be reduced by appropriate serial loading protocols.|
The mechanism behind what, in this case, can be considered proven ergogenic effects can be ascribed to the increase in pH after the exhausting initial bout of exercise; an increase of 0.11 ± 0.02 pH units (1.4%) (p Gough 2018).
Considering the non-significant increase in GI distress (Figure 3) that was observed, the scientists’ verdict that that “[f]uture research should continue to explore the role of NaHCO3 supplementation as a recovery aid in other combat sports” should yet be expanded to “role of bolus and serial loading with NaHCO3”. Where that’s practically feasible (considering time-constraints), the serial loading may well eliminate the (albeit tolerable) side effects that were observed in the study at hand.
- Amerigo Rossi, M.A. et al. “The effects of a novel bicarbonate loading protocol on serum bicarbonate concentration: a randomized controlled trial.” Journal of the International Society of Sports Nutrition 16.1 (2019): 1-7.
- Amodu, Afolarin, and Matthew K. Abramowitz. “Dietary acid, age, and serum bicarbonate levels among adults in the United States.” Clinical Journal of the American Society of Nephrology 8.12 (2013): 2034-2042.
- Gough, Lewis A., et al. “Post-exercise supplementation of sodium bicarbonate improves acid base balance recovery and subsequent high-intensity boxing specific performance.” Frontiers in Nutrition 6 (2019): 155.
- Frassetto, L., R. Curtis Morris Jr, and A. Sebastian. “Potassium bicarbonate reduces urinary nitrogen excretion in postmenopausal women.” The Journal of Clinical Endocrinology & Metabolism 82.1 (1997): 254-259.
- Kurtz, Ira, et al. “Effect of diet on plasma acid-base composition in normal humans.” Kidney international 24.5 (1983): 670-680.
- Sebastian, Anthony, et al. “Improved mineral balance and skeletal metabolism in postmenopausal women treated with potassium bicarbonate.” New England Journal of Medicine 330.25 (1994): 1776-1781.