Sodium Bicarbonate and Muscular Fatigue - An Experiment
Sodium Bicarbonate (aka baking soda). One of the cheapest ergogenic agents around? We will see.
Recently, I was listening to Ben Greenfield and heard him mention his use of Sodium Bicarbonate (NaHCO3) in a glass of water every morning because of it's alkalinizing properties. He also mentioned the use of NaHCO3 as an ergogenic aid for high intensity endurance athletes. Theoretically, this makes a lot of sense to me. So, I decided to self experiment and want to tell you about my experience. Some necessary disclaimers here... Yes, I am a molecular biologist by training and run experiments for a living... But this is by no means a controlled setting. My sample size is 1 and the data has not been replicated. The design was not blinded and I have no controls, positive or negative. Finally, this is by no means my area of "expertise". This is not a true experiment but just an anecdote of my experience toying with exercise.
Sodium Bicarbonate, also known as Baking Soda, can be purchased from practically every grocery store in North America. I actually picked up a box of "Nice" baking soda from the Duane Reade downstairs for ¢99 for this particular test. The theory behind why sodium bicarbonate can help delay the onset of muscular fatigue is pretty complex but I will explain it briefly here...
Bicarbonate (HCO3-) when found in the blood will act as a "buffer" (neutralizer) limiting the adverse effects of a lowering blood pH resultant of anaerobic exercise. Confusing, I know. When exercising aerobically, your blood flow and oxygen consumption are sufficient to produce energy without producing abnormal levels of lactic acid and protons (H+) in the contracting muscles. This is an example of when you are jogging with a friend and holding a conversation and you feel like you could continue for hours. Your body is able to keep up with the acid formation and can even recycle some of the acid as more fuel, pretty incredible. The problem arises when your blood flow or oxygen consumption cannot keep up and you go "anaerobic". This is when you go red in the face, huff and puff, and sometimes even loose your lunch. At this point you get an accumulation of lactic acid and protons (H+) in your contracting muscles (that familiar BURN) that cannot be cleared and continues to accumulate. Based on diffusion gradients, the acid will move from really high concentrations in the muscle body toward the lower gradients found in the blood. This will cause your blood pH to drop (acids are low pH, bases are high pH) as the acid accumulates in your blood and is known as blood acidosis. The abnormal accumulation of acid in your muscles and blood can inhibit enzymes involved in oxidative phosphorylation, glycogenolysis and glycolysis (energy production). It can also increase muscular potassium release and reduce calcium release and binding to tropin C. Finally, it can inhibit the sarcoplasmic reticulum enzyme Ca-ATPase necessary for muscle function. These are all fancy ways to say that it will cause muscular fatigue and make you want to quit exercising. This is why you can only sprint 100m and not 26.2 miles. The slower you go, theoretically, the longer it takes before burnout. Well, bicarbonate circulating in the blood (it wont diffuse all of the way into your muscles) is actually incredibly good at neutralizing this acid, returning your blood pH to normal levels (Blood pH - 7.35 in the normal human if you're interested). As you neutralize the lactic acid and protons in your blood, it will increase the gradient from muscle to blood. This will cause more lactic acid and protons to flow from your muscles into your blood, essentially causing an efflux of toxins out of your muscles. Viola! Simple, right?
Some of my scientific literature and calculations for my optimal dose. I don't want the poops.
It is important to note, when you injest NaHCO3, it interacts with the Hydrochloric acid in your stomach (HCL + NaHCO3 = H20 + C02+ NaCl). This process destroys the bicarbonate (HCO3-) and renders it inactive. This is why it is recommended to take this supplement on an empty stomach so that it reaches the small intestines as quickly as possible where it can be readily absorbed into the blood stream. It is also important to note that high doses will cause significant GI (gastrointestinal) issues including gas, bloating and diarrhea. All not good when you are going out to exercise. I will say here, consult with a doctor and do your research before trying any ergogenic aid. I have read multiple scientific articles and most cite that a dose of 0.2-0.3 g/kg is the optimal dose consumed at a minimum of 40-60 mins prior to exercise.
Experimental design: I decided that I would take 15 g (0.24g/kg for me) of NaCO3 dissolved in a big old glass of water. Then, 40-50 mins post ingestion, I would begin my scheduled 1h45m time trial (TT) effort at 80% of my Functional Threshold Power (FTP).
FTP is the maximum power (effort) that a rider can hold on the bike for 60 mins if everything were absolutely perfect and he was "highly" trained. Any cyclists out there knows that holding this power for an hour is incredibly difficult. So, 1h45m at 80% FTP is doable but far from enjoyable. A perfect test.
Leading up to this experiment, I had been consuming a high fat, moderate protein and low carb diet. I would estimate that I had consumed <100g of carbs all day and this TT began at about 8:00 pm in the evening. It's safe to say that I was in a predominantly fat burning state, which is what I aim for on a daily basis. My plan was to go about my workout as per usual and compare my Wattage (work) and rate of perceived effort (RPE) over the entire workout to previous attempts. Another disclaimer - A day earlier, I had put myself through a pretty aggressive supra-threshold (above FTP) interval workout and was feeling a little fatigued to begin with. What can I say, I couldn't mess up my training schedule for this.
Go time!
Results: Firstly, I will say that consuming a glass full of baking soda is not on my list of enjoyable activities. The overwhelming taste of salt makes it pretty difficult to get down. You definitely want to mix it with pretty large quantities of water (I did 8 oz but would suggest more) to ensure that you limit the risk of the aforementioned side effects. Remember to consume the mixture on an empty stomach. This not only helps with GI issues but will ensure more bicarbonate will be transported to the small intestine rapidly. I took fifteen minutes to drink the mixture down, which also helps limit the GI distress. Imagine pouring water or HCl on a pile of Baking Soda, thats what will happen in your body. After finishing the drink, I took the dog for a walk and set up the indoor trainer. Exactly 45 mins after ingestion of the solution and with only a moderate feeling of "fullness" in my belly, I was off to the races.
I spent 15 minutes solidly warming up as per usual. I could definitely still feel the residual fatigue in my legs from the previous workout. I would go as far to say that I may have been quite glycogen depleted because of the workout and my lack of carbohydrate re-feeding. I will point out, these are not the symptoms I was expecting to minimize with the use of bicarbonate. A work effort of 80% FTP is right around 3.0 watts/kg for me. I maintained this power for the first 45 minutes putting me at the one hour mark in my workout (pictured below). I will say right now, the whole first hour was miserable. My legs felt heavy, my attitude was negative and I thought there was no way I could hold on to this type of power for another 45-60 mins. I figured my experiment was over. Apparently, all of this research about Sodium Bicarbonate just didn't apply to me. This is not an abnormal thing in research, we usually just call people like me non-responders. I decided that I would take a carbohydrate gel (CLIF Shot Energy Gel) and get as far through my workout as physically possible. So now, my non-experiment is truly a non-experiment. I have introduced two new variables... Carbohydrates and Caffeine... Both ergogenic agents in their own right... But hear me out.
Within 5 mins of taking the gel, I started to feel my legs come back. A group of riders passed me on a hill on the Richmond, VA course of Zwift and I decided to try and power onto the back of their group, another pretty aggressive move in cycling. Also, this was not at all prescribed in my TrainerRoad workout. I hit about 4.5 watts/kg for around 30s and then backed off to 3.5 taking advantage of the draft. My legs felt solid, that notorious burn felt non existent after a few seconds. Oddly enough, I didn't have a significant change in heart rate either. After a handful of minutes, the riders slowly began to pull away but I maintained my 3.5 watts/kg, steadily. I had a new found pep and increased attitude (the attitude was most definitely due to the calories I had ingested). Now, I know all of this can be attributed to the carbs and the caffeine but it truly felt like something more was there. I had the ability to finish out my workout strong, above the expected power feeling relatively fresh, like I could do another 30-60 mins even. I have never felt that way on long TT efforts, regardless of taking fuel on board during the workout or not. Interesting.
Here is my ride summary from Trainer Road. I run Trainer Road and Zwift concurrently for solid training sessions and entertainment purposes. You can clearly see a dramatic change in power (and you can trust me a dramatic change in mood) around the 1h mark. You can also note that there is not a significant jump in my heart rate, as I would expect with the increased workload. I left the test feeling strong and could have even continued at that power output for substantially longer... I think.
Discussion: Why? Why did it take so long for this so called ergogenic aid to kick in? Was there even an effect related to the bicarbonate or was it due to the intake of sugar and caffeine. Is there an additive effect of Bicarbonate, Caffeine and Carbohydrates? Well, like any good experiment, I come out with more questions than answers but I will tell you my hypothesis moving forward. I think I went into this workout burning fat as my predominant source of fuel and with minimal glycogen stores. On top of that, I never took my power over that of my threshold (which would have been close to my barrier of aerobic and anaerobic work). As a matter of fact, I only worked up to 80% of my FTP (slowly) which meant that I theoretically was in a strongly aerobic zone based on my training. This type of effort requires a lot of oxygen and can use fat as the primary source of fuel. In highly fat adapted athletes (which I consider myself pretty well fat adapted), you will use very little glycogen for fuel (stored glucose) in a workout such as this. That allows me to save my precious and limited glycogen stores for strong efforts (sprint finishes, catching another racer, steep inclines, etc.). This form of work should not technically produce a buildup of lactic acid or H+ in my muscles, meaning that the use of bicarbonate is kind of unnecessary. However, when I was about to give up and took a large quantity of simple carbohydrates on board as a last resort, everything in my body changed. I was now absorbing readily available glucose into my blood through digestion which could be easily used as a high performance form of fuel along with the triglycerides in my blood. This gave me that added pep to introduce more power and see more of the effectiveness of this blood buffering as higher levels of lactic acid and protons were produced.
I can say this, I don't know if that vile drink improved my workout because I don't know what I could have achieved without it if all other variables were the same... but it gave me the confidence to try it again. I would love to get into a controlled laboratory setting and test two things that I find lacking in the literature at the moment.
1) Do you see similar ergogenic effects of Sodium Bicarbonate in highly fat adapted endurance athletes compared to your typical sugar burner athletes?
2) In >4 hour events, does a chronic dosing improve performance compared to a single pre-exercise dose?
The closest study that I have seen to this chronic dose was a study done in tennis players where they took a "top up" after the third "simulated game". However, these participants were only compared to a NaCl (Salt) control group, not a pre-exercise treated group.
Anyways, I am rambling. Let me know if you have any questions or if you have heard of any other crazy exercise hacks you want me to look into. Keep an eye open for an update as I continue to experiment with Sodium Bicarbonate.