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by Alan McCubbin
June 21, 2016
Photography by Melissa Baldwin/Flickr
For years now, cyclists and other athletes have been using sodium bicarbonate in an attempt to legally improve performance. So just how does this household baking ingredient work in a sporting context and how effective is it? And if you’re going to take it, what’s the best way to go about it? Dietitian Alan McCubbin investigates.
It was the late ’90s and an Australian Olympic track star sat waiting for the start of the kilo. “I didn’t know if I was going to break a world record or s#@t my pants!”, he recalled years later.
This is the exact description I was given when discussing sodium bicarbonate supplementation at a Cycling Australia coaches course a few years ago. And it’s a common story among track riders who have dabbled with this method of nutrition supplementation – it can make you faster, but it also has the potential to go horribly wrong (more on that later).
So what is sodium bicarbonate and what makes it a potential sports supplement?
Most of us think of sodium bicarbonate as bicarb soda, the stuff you use in baking as a raising agent. Sodium bicarb on its own is alkaline and will react with acids to neutralise them. For this reason it’s often referred to in biological terms as a buffer, a substance that can prevent (or buffer against) a rise in acidity when the amount of an acid increases.
In a sporting context, the sodium bicarb you swallow is absorbed into your blood, increasing the amount of blood bicarbonate and lowering its acidity (raising its pH). This then acts as a buffer for the blood against increasing acidity that results when hydrogen ions (produced alongside lactate) are formed during high-intensity (anaerobic) exercise.
In short, more bicarb in the blood means you can produce more lactate with less of an increase in blood acidity. This theoretically increases your ability to exercise at very high intensities.
The concept of buffers for sports performance is by no means new. Research into manipulating blood acidity and performance goes back to the late 1920s. More recently, research into sodium bicarb as a sports supplement took off in the 1980s, with studies finding improved 400m and 800m running performances.
Since then, sodium bicarb has been studied in numerous sports where muscle and blood acidity may be a performance-limiting factor – sports like rowing, middle-distance running, swimming and repeated sprint efforts in team sports.
In cycling, much of the focus has been on the track, due to the short duration and high-intensity nature of the events. And there are several studies showing improved performance during efforts of around one to four minutes (think the sprint events through to the team pursuit). Improvements seem to be around 3% to average power output during efforts of around three or four minutes.
As for the road, studies of longer efforts that resemble road racing generally haven’t shown performance benefits. But what about the high-intensity efforts that come at the end of an hour (or more) of lower intensity riding? This sort of pattern is often seen at the pointy end of a crit, or the last kilometres of a road race, preparing for and then executing a sprint or an uphill attack to the line.
There are fewer studies in this area, but there are suggestions that sodium bicarb may be effective in certain scenarios.
Firstly, the high-intensity efforts have to be hard enough that lactate production and the accompanying rise in muscle and blood acidity is performance-limiting. You have to have enough left in the tank at the end of a race to produce that kind of power. The other factor to consider is that bicarbonate peaks in the blood around 1-3 hours after you consume it, before declining back to pre-supplementation levels.
So if you’re racing for several hours, then consuming bicarb just before a race might be too early for it to have any beneficial effect.
On that note, how much, when and how do you take sodium bicarb? The optimal dose to provide a benefit to performance is around 0.3 grams per kilogram of body weight. So for a 70kg athlete that’s 0.3 x 70 = 21 grams, or 21,000mg. This amount can be controlled using capsules of a known quantity (such as Sodibic from a pharmacy), or by weighing out bicarb soda powder (the stuff you use in baking) and taking it with water.
There are pros and cons to both approaches. Sodium bicarb powder is cheaper compared to capsules but tastes horrible, making the capsules an attractive option despite the extra cost. On the flip side, each Sodibic capsule contains just 840mg, so to get the 21,000mg you’d have to down 25 capsules in quick succession!
The gut problems mentioned earlier can occur because large amounts of sodium bicarb cause water to be drawn into the intestinal tract. As a result, some people experience varying degrees of nausea, stomach pain, vomiting and diarrhoea, with higher doses likely to cause more problems. However research published in 2011 at the Australian Institute of Sport shed some light on the most effective protocols for bicarb loading, to maximise the benefits and minimise side effects.
The study compared eight different methods of bicarb loading. It showed that either capsules or powder should be taken around three hours before competition, and consumed with plenty of water (around 7mL per kilogram of body weight, or 490mL for a 70kg athlete). Having a meal or snack at the same time also reduced the side effects.
The timing of bicarb loading is also important when it comes to performance. The traditional view has been that the maximum effect on blood pH occurs between 2-3 hours after consumption, so taking bicarb 2-3 hours before a training session or competition will achieve the maximum benefit to performance. However new research published in March 2016 suggests there is a significant difference between individuals in the time it takes for bicarbonate to peak in the blood, ranging from 75 to 180 minutes after consumption. The authors also suggested that other factors like the amount and timing of food may also be important.
They’ve suggested that in elite sport, athletes need to test their race-day protocol beforehand in the lab, following their usual race schedule (including meals in the hours leading up to it) and have their blood bicarbonate and pH measured to determine the best timing for them.
Finally, what about combining sodium bicarb with other supplements such as beta-alanine (another type of supplement that buffers acidity, this time in the muscle itself) or caffeine? There are now several studies looking at the combination of bicarb loading with these supplements – almost all of them show no benefit to combining supplements compared to either supplement alone.
And this gets to my final point – with the horrible taste, the huge number of capsules to swallow and the potential for things to go (horribly) wrong with sodium bicarb supplementation, is it even worth the risk? It has the advantage over beta-alanine that you only need a one-off dose (as opposed to several doses a day for weeks with beta-alanine), but I would argue that the performance benefits from caffeine are similar to bicarb for most people and with much less in the way of side effects.
There will be some people that don’t tolerate caffeine or don’t seem to get a benefit from it (researchers like to call these people “non-responders”), but for everyone else – and that’s most people – I would suggest that a coffee or two is going to be a tastier, less risky and just as effective way to go, on the track and the road.
Alan McCubbin is an Accredited Sports Dietitian, Accredited Practicing Dietitian and past president of Sports Dietitians Australia. He is also the founder of Next Level Nutrition, an online sports nutrition consultancy through which he works with a range of athletes from recreational to Olympians.