Does Baking Soda Boost Endurance?

It’s a commonly used performance enhancer, but it has some limitations.

After finishing an indoor mile race one year, I grabbed a water bottle sitting next to my backpack to soothe the ‘track hack’ that always followed the first race of the winter. The team-issued water bottle, it turned out, was my teammate’s, not mine – and I got a horrid shock when I tasted the contents. It was full of baking soda, and the unexpected taste made me spew it out reflexively and almost throw up.

That was the first I heard about the performance-boosting effects of baking soda, which is one of the most extensively studied ergogenic aids around. The basic idea is fairly simple: hard exercise makes your muscles and blood more acidic; baking soda is a base, so it can partly counteract this acidification and, in theory, allow you to exercise a little harder or a little longer before exhaustion.

The general conclusion of baking soda studies is that it offers a small performance boost in short, hard races lasting between about one and ten minutes – precisely the kind of exercise bouts where you’d expect to see the highest levels of lactate and greatest increases in acidity. These results tend to have quite a bit of individual variation, partly because many people also experience gastrointestinal side effects. It’s hard to run a mile PB if you’ve got explosive diarrhoea.

But what about longer events? Could baking soda also help in a 10K, or a half-marathon? That question has received far less research attention, but it’s the focus of a new study from researchers at Saarland University in Germany (hat tip to Kamal Patel at Examine.com, who brought the study to my attention).

The researchers put 18 trained runners through two endurance tests that consisted of 30 minutes at 90 per cent of anaerobic threshold (as determined during a prior VO2max test) followed immediately by as long as possible at 110 per cent of anaerobic threshold (which turned out to be another nine or so minutes, on average). Before one of the tests, the runners were given baking soda at a dose of 0.3 grams per kilogram of body weight; before the other test, they were given a saltwater placebo.

The results, which were published in PLoS ONE, found no difference in time-to-exhaustion performance: 39.6 minutes with baking soda, 39.3 minutes with placebo. So the answer to the original question seems clear: no, baking soda doesn’t help in longer events. Still, there are some interesting points to consider in the results.

Though they didn’t see any improvement in the time trial, the runners did do better on their VO2 max tests when they had baking soda. The actual difference in VO2 max (61.2 versus 59.8 ml/kg/min) didn’t quite reach statistical significance, but the running speed in the final stage before they gave up was significantly higher. That’s because a VO2 max test (once you get through the easy early stages) is in the one- to ten-minute sweet spot.

Measurements of blood pH showed that the runners had significantly elevated acidity at the end of the VO2 max test; in contrast, there wasn’t a big change after the time-to-exhaustion test. The question of what, exactly, makes you give up at the end of a time-to-exhaustion test is an interesting (and controversial) one, but this data suggests that going ‘acidic’ (and the associated decline in muscle function) doesn’t contribute to making you hit your limits in longer endurance events.

Before discarding the idea that baking soda could be useful for longer endurance events, it’s worth noting that, since this was a time-to-exhaustion test, the pace was pre-set, eliminating any variations. In real life, of course, many races are determined by finishing sprints. It’s conceivable that baking soda would have no benefit during the vast majority of, say, a 10K, but allow you to kick home over the last kilometre or last 400 metres a little faster.

Interestingly, that’s exactly what a study of beta-alanine found a few years ago. Beta-alanine works in a similar way as baking soda; it counteracts acidity directly within muscles cells, instead of in the bloodstream. In that study, participants did a 110-minute simulated cycling race, followed by a 10-minute time trial and a 30-second sprint. There was no difference in the time trial, but the cyclists increased their average power during the final 30-second sprint by 5.0 per cent with beta-alanine compared to placebo.

A final point: the study started out with 25 subjects, but seven of them experienced such severe gastrointestinal side effects from baking soda that they couldn’t complete the study. In fact, 15 of the original 25 subjects had side effects, including “stomach ache (n = 6), diarrhoea (n = 5), nausea/vomiting (n = 2) and dizziness (n = 2).” That’s not good, and it’s probably the biggest reason to be wary of trying baking soda.

As it happens, that’s what my teammate’s experiences, back in college, taught me. Later that season, he was scheduled to run four races (two individual and two relay) at our conference championships – but after soda loading for his first race, he had explosive diarrhoea and had to scratch from the 4 x 800-metre relay. I was the alternate, so I got my big chance to run on the relay team. I set a three-second PB and earned a spot on the team for nationals, where I PB’d by another two seconds. It was a huge breakthrough for me, so I’ve always been grateful for the (indirect) performance effects of baking soda.


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