We all get nervous before a big race or a workout. Unfortunately, this can sometimes lead to one (or more) trips to the port-a-potty, perhaps derailing our pre-race routines. But the physical relief from going “number 2” might also be accompanied by a mental boost. A new study suggests a fascinating link between defecation and cognitive performance in elite triathletes. It appears that optimizing your pre-race bathroom habits could be more important than you think. This article delves into the science behind this “rectum-brain connection,” explores related topics like male athlete underfueling and fitness tracker insights, and offers practical advice for runners looking to gain a competitive edge.
Can a Pre-Race Poop Make You Faster?
Science might finally have your back. A new study on elite triathletes found that defecation (yes, really) led to improved cognitive performance on the Stroop test, a classic measure of executive function. Even more intriguing is that when athletes took magnesium oxide — an over-the-counter supplement known for its laxative effect — the cognitive boost was even stronger.
Could your gut be playing a bigger role in performance than we previously thought? And if so, what does this mean for runners? Let’s break it down.
Researchers conducted a study on 13 elite triathletes. Each participant performed the Stroop test — a cognitive task that measures reaction time and executive control — under three conditions:
- No defecation
- Defecation without magnesium
- Defecation induced by magnesium oxide supplementation
Pooping enhanced cognitive performance — every athlete performed better on the Stroop test after defecation, regardless of whether it was natural or magnesium-induced. However, magnesium made the effect even stronger. With magnesium, 100% of participants improved their test performance, compared to 69% who improved after non-magnesium defecation.
The researchers propose a potential “rectum-brain connection” — a direct link between gut activity and cognitive performance.
So, how can runners use this advice?
- While we already know that an upset stomach can ruin a race, this suggests that even minor gut irregularities might impact cognitive sharpness — which is crucial for pacing, strategy, and decision-making under fatigue.
- Pre-race bathroom habits might be more important than we thought. If defecation enhances cognitive function, going to the bathroom before a race might not just be about comfort — it could actually help optimize reaction time, focus, and execution.
Does this mean you should down magnesium supplements before every race? Not necessarily. Runners should be aware that too much magnesium could also lead to an upset stomach. But it does suggest that a pre-race “gut routine” should be a part of performance strategy, not an afterthought.
Read the full study at Sports Medicine and Health Science.
Male Athletes Are (Silently) Underfueling
Eating disorders are unfortunately common among endurance athletes, and the discussion has often focused on female athletes. But what about men?
New research highlights that male athletes are also at risk of Relative Energy Deficiency in Sport (RED-S), a condition that can impair health and performance due to chronic under-fueling.
Male athletes with low energy availability were nearly 3 times more likely to have cardiovascular dysfunction such as heart rate abnormalities or circulatory issues, 3.2 times more likely to have psychological illness such as anxiety or depression, and more likely to report gastrointestinal, immune, and metabolic issues. Under-fueling also wrecked performance. Athletes with low energy availability reported decreased training responses, poorer endurance performance, and lower levels of muscle strength, coordination, judgment, and irritability.
What this means for runners, coaches, and parents of athletes:
- Low energy availability is a bigger problem in male athletes than we think: RED-S is often thought of as a female athlete issue, but this study makes it clear that male athletes are at risk too.
- You don’t have to be underweight to have low energy availability: Athletes of all body types and abilities can suffer from RED-S if they fail to match energy intake to training demands.
- Training harder won’t fix poor fueling: A greater likelihood of a decreased training response means that more training doesn’t equal better performance if you’re not fueling properly. Runners experiencing stagnation, fatigue, or poor recovery should consider nutrition — not just training volume — as a potential culprit.
- Screening for REDs in male athletes needs to improve: Low energy availability is probably underdiagnosed in men because the symptoms are less obvious than in women.
If you or an athlete you know is training hard but struggling with fatigue, poor endurance, irritability, or mental burnout, it might not be overtraining — it might be under-fueling.
What Your Fitness Tracker Can (and Can’t) Tell You About Your Training Response
Wearables aren’t just for “biohackers” anymore — they’ve taken over endurance sports. We are constantly told these devices can optimize our training, recovery, and performance. And while data from our devices can be fun to look at, how much can it really tell us? And do these metrics actually predict how well we’ll adapt to training?
One metric did predict training adaptation: a combination of heart rate, heart rate variability, and breathing rate. The researchers referred to this metric as the “nightly recharge” score. Think of it as how much the nervous system recovers from night to night. This “recharge score” was strongly correlated with training adaptation. Runners with lower (worse) values during the overload period improved their 3-kilometer time less than those with better scores. Essentially, runners whose bodies didn’t fully “bounce back” overnight didn’t see as much performance improvement.
What does this study tell us about which metrics of recovery to focus on and which ones to ignore?
Many runners fixate on how many hours they sleep, but this study suggests that HRV, breathing rate, and even resting heart rate might be better indicators of recovery and adaptation than total sleep time, sleep quality, or sleep stages.
And let’s not forget that how you feel still matters. We often ignore subjective recovery cues because they “don’t feel accurate.” But muscle soreness and perceived strain clearly reflected training load in this study, suggesting that simple self-assessments can be just as important as high-tech tracking.
So, should you check your HRV every morning? Maybe. But don’t ignore the old-school method of listening to your body — it might be just as effective. Ultimately, the ideal approach is to use both. A combination of wearable recovery metrics and subjective recovery ratings could be the best way to adjust training and prevent overtraining. It’s the best of both worlds.
The free full text of this study is available from the journal Sensors.
Running Low on Carbs? Caffeine Can Save Your Performance
A new study tested whether caffeine supplementation could counteract the performance drop typically seen with carb-restricted training.
The Fasted + caffeine group burned significantly more fat than the Fed group during exercise the next morning, and contrary to the researchers’ hypothesis, Fasted alone did not boost fat oxidation compared to Fed.
Fasting + caffeine outperformed Fasted in the 20-minute time trial by 7%, averaging 189 Watts compared to 177 Watts. This group also tended to outperform the Fed group by 4.2%.
Caffeine didn’t just counteract the downsides of carb restriction — it may have actually improved performance. In fact, caffeine appeared to mimic some effects of carbohydrate fueling by elevating blood glucose and increasing fat oxidation.
How can you apply this to your training?
If you train fasted (by choice or necessity), caffeine might help you maintain intensity without bonking. Just be wary that too much fasted training could compromise recovery and performance. Proper fueling is still the key to success. But if fat adaptation is your goal, caffeine might be a better tool than carb restriction alone. Instead of starving your muscles overnight, you might get similar (or better) fat oxidation benefits simply by taking caffeine before a workout.
Read the full study in Current Developments in Nutrition.
Do Bigger Runners Need More Carbs?
Ever wondered why most nutrition advice for runners is tailored to the masses, but rarely to the individual? A recent discussion in the sports science community is challenging the one-size-fits-all approach to carbohydrate intake during exercise, suggesting that body weight might play a more significant role than previously thought.
By including a broader range of body weights in their study, they discovered that heavier athletes might benefit from higher carbohydrate intakes during exercise, as their absolute energy expenditure is greater — athletes weighing over 70 kilograms burned about 13 more grams of glucose per hour when exercising at 95% of their lactate threshold for 2 hours compared to athletes weighing under 70 kilograms.
Instead of adhering strictly to generic guidelines, consider adjusting your carbohydrate consumption based on your body weight. For example, if you’re a heavier athlete, you might experiment with increasing your intake slightly above standard recommendations to see if it improves your performance and energy levels. As with any nutritional strategy, it’s crucial to pay attention to how your body responds. Start by making small adjustments to your carbohydrate intake during training sessions and monitor for any signs of gastrointestinal discomfort or changes in performance.
Read the full blog post on My Sport Science.
Muscle Damage Affects Your Running Gait for Days after a Workout
If you’ve ever felt like your stride is off in the days following a hard workout, you’re not imagining things. Downhill running, sprinting, and even tempo runs can lead to muscle soreness lasting several days (it’s even worse if you’re just getting back into shape after a layoff). This is your body adjusting, trying to protect itself — but is this a good thing or a problem? The answer might be both.
On the one hand, soreness can indicate adaptations are occurring. But soreness can also cause us to change our form, potentially elevating injury risk.
All of this tells me that if you hammer a downhill session or a tough speed workout, expect subtle biomechanical changes for at least 48 hours. Because stride length is reduced, your pace and efficiency might suffer for a couple of days after. Planning easier, flatter runs could help prevent lingering movement alterations. Give yourself a few days of well-earned recovery before going hard again — or at least wait until you feel like your normal running gait has returned.
This study was published in the Journal of Science and Medicine in Sport.
We’ve explored a range of intriguing topics, from the surprising benefits of a pre-race poop to the importance of recognizing underfueling in male athletes. We’ve also considered how fitness trackers can both help and hinder our training, the potential of caffeine to boost performance in carb-restricted workouts, the need for personalized nutrition based on body weight, and the impact of muscle damage on running gait.
The key takeaways are clear: listen to your body, fuel it adequately, use technology wisely, and don’t underestimate the power of a well-timed bathroom break. By integrating these insights into your training and racing strategies, you can optimize your performance and run healthier for longer.