Sodium Bicarbonate for Runners: Does Baking Soda Work?

How does sodium bicarbonate actually work?

Hard running floods the muscle and blood with hydrogen ions, and this rising acidity is one of several factors thought to contribute to fatigue. Sodium bicarbonate raises the concentration of bicarbonate in the blood, increasing the body's capacity to buffer, or mop up, those hydrogen ions as they leave the working muscle. The idea is that by keeping extracellular pH higher for longer, you delay the point at which acidity limits force and pace.

The classic demonstration comes from Wilkes et al. (1983), who gave six trained middle-distance runners 0.3 g/kg before a simulated 800 m. Race time fell by about 2.9 seconds, roughly 1.8 per cent, and this was accompanied by higher post-race blood lactate and extracellular hydrogen ion levels, exactly the fingerprint you would expect if enhanced buffering had allowed the runners to tolerate more anaerobic work before slowing. The mechanism is extracellular, which helps explain why the benefit is concentrated in short, intense efforts.

Which running events benefit most?

The evidence points firmly at high-intensity efforts of short-to-moderate duration. The International Society of Sports Nutrition concludes that bicarbonate is ergogenic for exercise lasting roughly 30 seconds to 12 minutes, running included (Grgic, Pedisic, et al., 2021). An umbrella review of eight meta-analyses put the pooled effect for events of about 45 seconds to 8 minutes at around 0.40, a small-to-moderate benefit, and also found gains for high-intensity intermittent running (Grgic, Grgic, et al., 2021).

In practice this maps onto middle-distance track running. Bird et al. (1995) had twelve runners complete simulated 1500 m trials significantly faster on bicarbonate, 253.9 seconds versus 256.8 on placebo and 258.0 in the control, with no difference between placebo and control. That last detail matters: it argues the effect was genuinely pharmacological rather than a placebo response. If your target sits in that few-minutes window of near-maximal effort, bicarbonate has the strongest supporting case.

What does the latest running meta-analysis show?

The most rigorous recent synthesis specific to running is sobering. Miller et al. (2025) pooled 11 randomised, double-blind, placebo-controlled trials covering 126 participants and found that a single dose of sodium bicarbonate produced only a negligible, non-significant improvement in continuous running performance overall, with a standardised mean difference of 0.18 (95% CI -0.01 to 0.36, p = 0.06). In plain terms, across the trials as a whole the effect could not be distinguished from zero.

There was one nuance. In male-only cohorts the effect was small but statistically significant (SMD = 0.40), hinting that some of the dilution comes from mixed or female samples where the response has been less consistent. This fits older work such as Tiryaki and Atterbom (1995), who found no significant 600 m benefit in trained women despite clear rises in blood pH and bicarbonate. The overall message is that continuous running responses are variable and, on average, modest.

Does it help longer endurance running?

For prolonged running the evidence is weak. Freis et al. (2017) gave 18 trained runners 0.3 g/kg and saw a small increase in maximal running speed during a graded test, 17.4 versus 17.1 km/h, but no improvement at all in time to exhaustion during prolonged constant-load running, 39.6 versus 39.3 minutes (p = 0.78). Fifteen of the eighteen also reported gastrointestinal side effects. So even where a marginal high-intensity marker shifted, it did not translate into lasting longer.

This aligns with the broader pattern. Buffering helps most when acidosis is a rate-limiting factor, which is far less the case in aerobic, sub-threshold running than in an all-out middle-distance effort. Combined with the negligible pooled result from Miller et al. (2025), the practical conclusion for 10 km, half-marathon and marathon runners is that bicarbonate is unlikely to be worth the gut risk. It is a middle-distance and interval tool, not a marathon one.

What about intermittent and interval running?

One setting where bicarbonate looks more promising is repeated high-intensity running with short recoveries, the demand pattern of interval sessions and many field sports. Krustrup et al. (2015) tested 13 trained men on the Yo-Yo Intermittent Recovery test level 2, a protocol of repeated shuttle runs to exhaustion. With 0.4 g/kg of bicarbonate, running distance rose by 14 per cent, 735 versus 646 metres, alongside higher blood pH, bicarbonate and peak lactate, and lower perceived exertion.

That combination of more work done at a lower sense of effort is a plausible mechanism for benefit in repeated near-maximal bouts. The umbrella review similarly rated the evidence for high-intensity intermittent running and Yo-Yo performance as more certain than for steady endurance (Grgic, Grgic, et al., 2021). If your key sessions are hard reps with incomplete recovery, this is the scenario where a runner might reasonably experiment, bearing in mind the 0.4 g/kg dose used here sits at the higher, more gut-provoking end.

How much should you take, and when?

The ISSN position stand gives clear practical guidance (Grgic, Pedisic, et al., 2021). The optimal single dose is 0.3 g per kilogram of body mass, taken 60 to 180 minutes before the effort. The minimum effective dose is around 0.2 g/kg, and going higher does not help: doses of 0.4 to 0.5 g/kg add no further performance benefit while increasing the risk of gastrointestinal distress.

For a 70 kg runner, 0.3 g/kg works out at roughly 21 grams, which is a substantial amount of sodium bicarbonate and a meaningful sodium load. Timing is individual, because the blood bicarbonate peak varies between people, so the honest advice is to trial it in training rather than debut it on race day. The position stand also notes that spreading intake over a multi-day loading protocol can reduce gut symptoms while still raising buffering capacity, an option worth considering for those who react badly to a single acute dose.

Can you avoid the stomach trouble?

Gastrointestinal distress is the defining downside. In the Miller et al. (2025) meta-analysis, 29.5 per cent of bicarbonate users reported gut symptoms versus 2.6 per cent on placebo, and 8.7 per cent discontinued altogether. Nausea, bloating and diarrhoea shortly before a race are obviously self-defeating, and this variability is part of why average performance effects look so modest.

Newer delivery formats aim to sidestep the problem. Keverkamp and Scanlon (2025) tested the hydrogel-encapsulated Maurten Bicarb in eight collegiate endurance athletes running treadmill intervals at anaerobic-threshold pace. They found no significant differences in respiratory exchange ratio, perceived exertion, heart rate or blood lactate versus control, so in that small study it produced no measurable performance gain, but it notably avoided the gastrointestinal distress usually associated with bicarbonate. The fairest reading is that encapsulation may solve the tolerability problem without yet proving a clear performance upside, and the sample was tiny. More evidence is needed before treating it as a settled advantage.

Is sodium bicarbonate worth it for you?

Weigh it by event. If you race middle distance, an 800 m, 1500 m or mile, or your key sessions are hard intervals with short recoveries, the evidence for a small edge is reasonable and the supplement is cheap and legal (Wilkes et al., 1983; Bird et al., 1995; Krustrup et al., 2015; Grgic, Pedisic, et al., 2021). If you run longer, steadier distances, the case is weak and the gut risk probably outweighs a negligible, uncertain benefit (Freis et al., 2017; Miller et al., 2025).

Whatever the distance, treat it as an individual experiment, not a guarantee. Response varies by person and possibly by sex, roughly a third of users get gut symptoms, and higher doses only add side effects. Trial the 0.2 to 0.3 g/kg dose in training, consider multi-day loading or an encapsulated product if your stomach objects, and be honest about whether the marginal gain justifies the hassle for your goals.

Does sodium bicarbonate really improve running performance?

For high-intensity running of about 30 seconds to 12 minutes it can, with a small pooled benefit around an effect size of 0.40 (Grgic et al., 2021). Middle-distance trials show real gains, such as a faster 1500 m in Bird et al. (1995). But a 2025 meta-analysis of continuous running found only a negligible, non-significant overall effect (Miller et al., 2025), so it is event-specific rather than universal.

How much baking soda should a runner take?

The International Society of Sports Nutrition recommends a single dose of 0.3 g per kilogram of body mass, with a minimum effective dose near 0.2 g/kg, taken 60 to 180 minutes before the effort (Grgic, Pedisic, et al., 2021). For a 70 kg runner that is roughly 21 grams. Doses of 0.4-0.5 g/kg add no extra benefit and increase gastrointestinal side effects, so higher is not better.

Does sodium bicarbonate help marathon or long-distance running?

The evidence is weak. Freis et al. (2017) found no improvement in time to exhaustion during prolonged constant-load running despite a small rise in maximal speed, and Miller et al. (2025) reported a negligible overall effect for continuous running. Buffering matters most when acidosis limits pace, which is far less the case in steady aerobic running, so bicarbonate is not recommended for longer endurance events.

Why does sodium bicarbonate cause stomach problems?

A performance dose is a large amount of sodium bicarbonate, which draws water into the gut and can cause nausea, bloating and diarrhoea. Miller et al. (2025) found gut symptoms in 29.5 per cent of users versus 2.6 per cent on placebo, with 8.7 per cent discontinuing. Splitting the dose over several days can reduce symptoms (Grgic, Pedisic, et al., 2021), and encapsulated products may avoid them (Keverkamp and Scanlon, 2025).

Is Maurten Bicarb better than plain baking soda?

Its main advantage is tolerability. Keverkamp and Scanlon (2025) found the hydrogel-encapsulated Maurten Bicarb avoided the gastrointestinal distress usually associated with sodium bicarbonate, but in that small study of eight athletes it produced no measurable performance gain versus control. So it may solve the gut problem without yet proving a clear performance edge; more research is needed before treating it as superior.

Does sodium bicarbonate work equally well for women?

The evidence is less consistent. Miller et al. (2025) found the significant effect only in male-only cohorts (effect size 0.40), while the overall result across mixed samples was non-significant. Tiryaki and Atterbom (1995) found no significant 600 m benefit in trained women despite clear rises in blood pH. This does not prove it fails to work for women, but responses appear more variable, so individual testing is especially important.