Run Long, Run Healthy: Pacing Mistakes, Recovery Gels, and Supplements That Actually Make a Difference (and Some That Don’t)
June 26, 2025. Here's the free but abridged version of this week's Run Long, Run Healthy newsletter. Please consider subscribing to receive the full-text version.
Beta-Alanine Might Increase Your Endurance (But Not Your VO₂ Max)
Beta-alanine is one of those supplements that seems to have found its niche with cyclists and CrossFitters. Mechanistically, it raises muscle carnosine, which buffers hydrogen ions (H⁺) and helps delay pH-driven fatigue during high-intensity efforts. In the last few years, many have wondered whether it could benefit middle- or long-distance runners, especially those of us hitting the track or hammering intervals.
A new study tested that question by looking at whether 4 weeks of beta-alanine supplementation could improve endurance in competitive adolescent runners. Researchers enrolled 27 competitive middle- and long-distance runners (aged 15–19 with at least 3 years of training experience). Over a period of 4 weeks, athletes received either 6.4 g/day (for males) or 4.8 g/day (for females) of beta-alanine (divided into three daily doses with meals) or a placebo in equivalent doses.
During the 4 weeks, the participants visited the lab to complete three submaximal treadmill tests at 80% of their VO₂ peak for 1500 meters and three maximal graded exercise tests (a run to exhaustion on a treadmill where speed and incline increased every minute), during which physiological measures like heart rate, lactate, and oxygen uptake were measured.
Beta-alanine supplementation increased time-to-exhaustion by 6.5%, while the placebo group only improved by 1.4%. That’s equated to roughly 24 seconds longer at max effort for the beta-alanine group. However, VO₂ peak didn’t budge—the beta-alanine group saw a small 0.7 ml/kg/min increase, which was within typical day-to-day variability. In contrast, the placebo group actually declined slightly, but this may have been due to weight fluctuations or measurement noise. Other notable changes in the beta-alanine group included a lower heart rate and respiratory exchange ratio (RER) during submaximal running, suggesting improved metabolic efficiency. There were no meaningful changes in lactate accumulation during the maximal or submaximal tests (a surprising finding given the presumed mechanism by which beta-alanine works) and no differences in perceived exertion or oxygen uptake during the submaximal tests.
What this means for runners
If you’re a competitive runner doing interval-heavy training or racing events like the 800m to 5K where fatigue builds fast, beta-alanine might help you last longer at a given effort. Just don’t expect it to raise your aerobic ceiling.
This study focused on adolescents, and the intervention lasted only 4 weeks. We don’t know if benefits extend to adult runners or improve with longer use. But if you’re chasing small gains at high intensity, beta-alanine could be a tool worth considering.
What “Big Data” Can Teach Us About How to Pace a Marathon
In the marathon, pacing is key, and there’s always a “debate” about the best way to pace. Are even splits more effective, or is running a slight negative split the strategy for a new personal best?
A new massive study looked at ten years of real-world pacing data from over 146,000 runners in the Valencia Marathon and dug into how sex, age, and ability affect pacing success. I think we can learn a few things from its findings.
Researchers analyzed official race data from the Trinidad Alfonso EDP Valencia Marathon between 2014 and 2023, excluding 2020 due to pandemic constraints. They broke the marathon into nine 5k segments, then calculated absolute and relative speeds per segment, pacing profile (even pacing, positive, or negative based on half marathon splits), speed variability, “hitting the wall” (defined as a >7.3% slowdown between the 25–35k segments/miles 15—22), and whether runners produced a final “end spurt” (a kick) in the last 2.2k (1.5 miles) of the race.
Runners were sorted by sex, age group, and performance category (11 levels from sub-2:10 elites to 5:30+ finishers).
A few major trends emerged:
Even pacing was the most common strategy (used by ~75% of runners), and its use increased significantly in recent years, especially in 2022 and 2023.
Women paced more evenly than men (77.6% vs. 74.3%) and had lower variability, but they were more likely to hit the wall at both 30k and 35k (18.5 and 22 miles).
Slower runners were more likely to pace poorly and hit the wall. Sub-3:00 men and sub-3:15 women showed the most even pacing and least fatigue collapse.
Even-paced runners ran 27–34 minutes faster than those who used positive or negative pacing; that’s an enormous margin for such a simple strategy.
The 30–35k segment (miles 18–22) was consistently where pacing fell apart, especially for older runners and those under 23, both of whom showed higher variability and fatigue-related slowdowns.
“End spurts” were common, especially in slower runners and women, but they correlated with worse overall marathon times (perhaps an act of desperation instead of a winning strategy?)
Notably, pacing variability was strongly correlated with marathon time, and runners who hit the wall at 30k (~18 miles) lost an average of 36 minutes compared to those who didn’t. That’s a race-defining margin and one that’s likely avoidable through smarter energy distribution.
What this means for runners
Even pacing is one of the most powerful performance levers marathoners have. But it’s not evenly distributed. This study shows that your age, experience, and ability level influence whether you can pull it off. If you’re training for a marathon, practice pace control in addition to focusing on your fitness, especially in the mid-late stages of your long runs.
Does Intense Running Make Your Plantar Fascia More Injury-Prone?
The plantar fascia (a thick band of tissue on the bottom of your foot that supports the arch) is a workhorse in every stride, and while we know it plays a big role in running mechanics and injury risk, we still don’t fully understand how it responds to hard efforts. Most of the past research has focused on long, submaximal runs. But a new study asked: What happens after high-intensity interval running?
The study included 16 physically active adults (average age ~29) who performed a series of all-out 400-meter intervals on an outdoor track. The protocol was simple but brutal: five maximal 400s with a 1:1 work-to-rest ratio, then additional reps until the participants could no longer hit their target pace (most made it through 7–8 intervals total). Before the workout, immediately after, and again 30 minutes post-run, researchers used ultrasound and a technique known as shear wave elastography to assess plantar fascia thickness and stiffness, respectively.
The workout triggered clear, measurable changes in the plantar fascia. Thickness decreased by 0.43 mm immediately after running (from 3.29 mm to 2.86 mm), then partially rebounded after 30 minutes. Stiffness dropped significantly post-run (by 1.54 m/s), and while it improved with rest, it didn’t fully return to baseline. These changes were consistent regardless of sex or foot dominance. Importantly, the tissue showed signs of recovery within 30 minutes of unloading, consistent with normal behavior. The reduction in stiffness is particularly relevant—it’s been linked in other research to poor foot posture, increased pronation, and ultimately, a higher risk of plantar fasciitis.
What this means for runners
Hard running affects the plantar fascia in real, measurable ways, even in healthy, uninjured runners. After just one interval session, the plantar fascia temporarily loses some of its thickness and stiffness, likely due to fluid shifts and mechanical strain. The good news? It appears to recover quickly. But repeated high-load sessions without sufficient rest could nudge you closer to injury. Just make sure to put your feet up (literally and metaphorically) the day(s) after a hard workout.
Here’s what paying subscribers received this week in addition to the studies you just read. If you’d like access to the full RLRH newsletter, consider becoming a paid subscriber!
Topical magnesium gel is probably not helping you recover faster
Can colostrum supplementation improve your endurance and body composition?
The case for a high-intensity warmup
That’s all for now. Thanks for reading. As always—Run Long, Run Healthy.
~Brady~