What type of exercise is beta-alanine best for? Original paper

Basketball is a team sport involving repeated intermittent transitions between spurts of near-maximum to maximum intensity efforts and low-intensity to moderate-intensity activity.^[1] Beta-alanine, which combines with histidine in the body to produce carnosine, has a number of effects that might make it useful for basketball: it can enhance performance during intermittent and continuous exercise lasting from 30 seconds to 10 minutes,^[2] and mechanistic evidence suggests that carnosine has antioxidant properties.^[3]

Supplementation with beta-alanine may be useful for basketball players because it may enhance performance and prevent excessive increases in oxidative stress and inflammation that result from high training stress.

In this 8-week randomized trial, 20 male college basketball players (average age of 23) ingested either 6.4 grams of beta-alanine or a placebo daily while preparing for their upcoming competitive season. At baseline and after 8 weeks, the participants underwent testing for three days. The first day involved assessments of body composition and blood tests. The second day involved a repeated sprint test and power and blood lactate measurements. The third day involved an aerobic power test (i.e., the Bruce test) and maximal oxygen consumption (VO₂ max) and heart rate measurements.

The following outcomes were assessed:

• The markers of inflammation C-reactive protein (CRP) and interleukin 6 (IL-6)
• Body composition, assessed using multi-frequency bioelectrical impedance analysis
• Countermovement jump
• Power output
• Fatigue index (maximum power - minimum power/total time to complete the repeated sprint test)
• Blood lactate, assessed 10 minutes after the repeated sprint test
• VO₂max
• Heart rate

Beta-alanine decreased IL-6 compared to baseline (5.98 vs. 5.42 pg/mL) and placebo (5.42 vs. 6.15 pg/mL). It also decreased CRP compared to baseline (0.83 vs. 0.70 mg/L) and placebo (0.70 vs. 0.90 mg/L), whereas CRP increased compared to baseline with placebo (0.84 vs. 0.90 mg/L).

With respect to performance outcomes, beta-alanine increased peak power compared to baseline (862.1 vs. 881 watts) and placebo (881 vs. 858.3 watts).

A potential limitation of this study is the lack of control over training stress and nutrition, which can both influence inflammation. The researchers tried to control for potential differences in training stress by assessing the participants’ internal training loads using a rating of perceived exertion scale and a wellness questionnaire throughout the study, but internal training loads are limited by their subjective nature. Using tools to assess external training loads (e.g., a GPS device) would have helped to increase confidence that there weren’t meaningful differences in training stress between groups. Additionally, although the players were instructed to consume the same diet (which was recommended by a nutritionist) 72 hours before each testing period, there could have been longer-term differences in diet (e.g., micronutrient inadequacies) that influenced the outcomes.

High-intensity exercise induces high rates of ATP hydrolysis and glycolysis to provide energy. This results in corresponding increases in metabolic byproducts, such as inorganic phosphate and hydrogen ions, which reduce pH within muscle cells and impair force output and exercise performance.^[4] Other contributing factors to a loss of muscle function during intense exercise include alterations in calcium handling (i.e., decreases in calcium release from the sarcoplasmic reticulum and decreases in myofilament calcium sensitivity^[5]) and excessive reactive oxygen species (ROS) production.^[6]

Once ingested, beta-alanine combines with histidine in skeletal muscle and other organs to form carnosine.^[7] Carnosine plays several physiological roles in the body,^[3] one of which is acting as an intracellular pH buffer. Carnosine can mitigate declines in intracellular pH during exercise by binding to metabolic byproducts, which allows for longer sustained high exercise intensity. This is the primary mechanism by which beta-alanine enhances exercise performance, but it may not be the only mechanism. Preliminary evidence suggests that carnosine could also benefit high-intensity exercise performance by influencing calcium handling and ROS levels.^[8]

Because hydrogen ions and calcium compete for the same binding site in muscle cells (the former impairing muscle contraction and the latter triggering muscle contraction), and calcium and hydrogen ions competitively bind to carnosine, carnosine may improve contractile function by increasing myofilament (i.e., the proteins in muscle cells that produce muscle contraction) calcium sensitivity or the level of calcium ions available to induce muscle contraction.^[8] Carnosine also appears to possess antioxidant properties, including an ability to scavenge ROS and increase the activity of enzymatic antioxidants such as superoxide dismutase and glutathione peroxidase.^[3] Therefore, carnosine may help to prevent the production of ROS during exercise from getting out of control, which would preserve muscle function. Nonetheless, further evidence in humans is needed to confirm the contribution of these mechanisms to beta-alanine’s ergogenic effects.

An understanding of how beta-alanine can enhance exercise performance provides insight into the types of exercise that beta-alanine is likely to benefit, namely, high-intensity exercise characterized by an accumulation of hydrogen ions and a large increase in intramuscular acidosis. A 2017 meta-analysis reported that beta-alanine enhanced performance to a small extent during exercise lasting 30 seconds to 10 minutes.^[9] However, supplementation with beta-alanine is likely most effective for exercise lasting somewhere between 1 and 4–7 minutes.^[7][9]

Additionally, beta-alanine seems to be much more effective for enhancing exercise capacity (e.g., time to exhaustion) than performance (e.g., time to complete a time trial).^[9] It’s hypothesized that time trials may be influenced by pacing strategies,^[10] making performance less likely to be influenced by intramuscular acidosis. In contrast, in a time-to-exhaustion test, the latter stages of the test are characterized by maximal exertion and, consequently, a maximal production of hydrogen ions, so intramuscular buffering capacity becomes a critical limiter of performance.

With this information in mind, it’s not surprising that the reviewed study reported no changes in VO₂max or countermovement jump in the beta-alanine group. These results are supported by other evidence showing that beta-alanine generally has little or no effect on aerobic exercise parameters or measures of maximal force production, particularly in a nonfatigued state.^[11] That means there are a few puzzling findings in the present study: beta-alanine enhanced peak power during the repeated sprint protocol but did not improve minimum power, average power, or fatigue index. Based on the above, the opposite might be expected — in other words, no effect on peak power and an improvement in minimum power, average power, and fatigue index due to beta-alanine staving off fatigue, thus preserving muscle function and power output, particularly during the latter sprints.

The repeated sprint protocol consisted of six 35-meter sprints, with 10 seconds of rest between sprints. The lack of effect of beta-alanine on the aforementioned outcomes is most likely a consequence of the short duration of the sprints, resulting in a lackluster increase in intramuscular acidosis. According to data from one study, it takes female high school soccer players about 5.94 seconds to sprint about 36.6 meters.^[12] Thus, the sprints in the repeated sprint protocol were too short, far below the 30-second threshold where supplementation with beta-alanine has been shown to be beneficial.

According to one review on the topic, beta-alanine is unlikely to provide an ergogenic effect in repeated effort protocols featuring short efforts (no more than 10 seconds) and short recovery periods (no more than 60 seconds).^[11] Rather, beta-alanine is much more likely to provide an ergogenic effect in repeated effort protocols featuring longer efforts (at least 30 seconds) and longer recovery periods (more than 3 minutes).

So, there’s an explanation for why beta-alanine didn’t improve minimum power, average power, or fatigue index in this particular study, but why did beta-alanine enhance peak power output?

Evidence suggests that beta-alanine does not enhance peak power output directly,^[13][14] and most studies do not report an increase in peak power output in the group that supplemented with beta-alanine compared to the group that supplemented with a placebo.^[11] However, there are some exceptions. For instance, a study involving Korean national team boxers and a study involving professional alpine skiers both found evidence that beta-alanine enhanced peak power output.^[15][16] A commonality between these two studies and the reviewed study is the inclusion of competitive athletes engaged in an off-season training program.

Given the lack of a concrete mechanism to support why beta-alanine would directly enhance peak power output, the most probable explanation for these findings is that beta-alanine indirectly enhanced peak power output. Specifically, beta-alanine improved exercise performance during the off-season training program, resulting in greater total training volumes performed by the participants who supplemented with beta-alanine, meaning that these participants experienced superior training adaptations, which ultimately contributed to an increase in peak power output. This finding has also been reported elsewhere.^{[17][18][19][20]}

A limitation of this hypothesis, however, is that none of the aforementioned studies that reported an improvement in peak power output with beta-alanine provided sufficient data to confirm that higher total training volumes were performed in the beta-alanine group. Nonetheless, it seems to be the most plausible explanation available, at least if there was indeed a true effect and these weren’t spurious findings.

For example, a 5-week randomized controlled trial that had the participants perform a lower-body resistance exercise circuit (each exercise was performed for 20–40 seconds using about 60% of 1-repetition maximum and separated by 60–120 seconds of rest) reported improvements in power output when lifting maximal loads in the group that supplemented with beta-alanine.^[19] The researchers attributed the superior results in the beta-alanine group to performing a greater amount of training volume throughout the intervention, which resulted in an improved adaptive response.^[19] However, total training volume performed during the intervention was not reported.

It isn’t always the case that beta-alanine indirectly enhances peak power output by bolstering adaptations to a training program. Otherwise, an increase in peak power output or an improvement in performance during exercise lasting less than 30 seconds would be common in studies that have participants supplement with beta-alanine, not uncommon. For beta-alanine to indirectly enhance peak power output, supplementation needs to be combined with a training program that primarily stresses the glycolytic pathway and produces large increases in intramuscular acidosis.

In sum, supplementation with beta-alanine can improve performance during high-intensity exercise lasting about 30 seconds to 7 minutes. Practically, the following types of exercise are likely to benefit from supplementation with beta-alanine: 400-, 800-, and 1,500-meter running, 4-kilometer cycling, 2,000-meter rowing, combat sports, water polo, and 100-, 200-, and 400-meter swimming.^[11][9] Beta-alanine may also benefit certain types of resistance exercise by increasing the amount of volume performed. Specifically, resistance exercise programs made up of workouts that stimulate multiple muscle groups, use multiple sets per exercise, include a moderate to high number of repetitions (about 8–20 repetitions) each set, and include moderate rest intervals (60–120 seconds) between sets.

What sports can beta-alanine benefit?