Stress can quietly change the way people judge how much effort they have left during physical tasks, especially when it comes to reps in reserve. Reps in reserve is a term used to describe how many more repetitions someone feels they could do before reaching complete exhaustion. Normally, people rely on their body’s signals and past experience to make this judgment. But when stress enters the picture, things can get a little off track.
When someone is under stress, their brain and body react in ways that can make it harder to listen to those internal signals. The stress response activates the sympathetic nervous system, which is responsible for the “fight or flight” reaction. This means the body becomes more alert and ready for action, but it also means that some of the brain’s usual functions, like clear thinking and accurate self-assessment, can be dulled. The prefrontal cortex, which helps with decision-making and self-control, doesn’t work as well under stress. This can make it harder to judge how much energy is actually left in the tank.
Stress also changes the way people process emotions and mixed feelings. In calm situations, feeling mixed emotions—like being both tired and motivated—can be confusing and even harmful to well-being. But when stress is present, those mixed feelings can actually help a person cope better with tough situations. This means that under stress, someone might push themselves harder than they would otherwise, ignoring the usual signals that tell them to stop. They might think they have more reps in reserve than they really do, simply because their brain is focused on getting through the challenge rather than accurately judging their limits.
Another factor is how stress affects the way people see fairness and accept decisions. Research shows that people under stress are more likely to accept outcomes that aren’t entirely fair, and this can extend to how they judge their own performance. An athlete under stress might accept a higher level of fatigue or discomfort, thinking it’s normal or necessary, even if their body is signaling that it’s time to stop. This can lead to overestimating reps in reserve and potentially pushing too hard, which increases the risk of injury or burnout.
Stress also plays a role in how people handle being judged by others. Feeling judged can make someone feel vulnerable and stressed, which can further cloud their ability to judge their own limits. When someone feels they are being watched or evaluated, they might push themselves harder to prove something, even if it means ignoring their body’s signals. This can make it even harder to accurately judge reps in reserve, as the focus shifts from internal cues to external pressures.
In short, stress changes the way the brain and body work together to judge effort and limits. It can make people less accurate in judging how much they have left, more likely to push themselves too hard, and more influenced by external factors like being watched or judged. This means that under stress, the usual signals that help someone judge reps in reserve can become less reliable, leading to decisions that might not be in their best interest.
Sources
https://pmc.ncbi.nlm.nih.gov/articles/PMC12611808/
https://attorneytherapists.com/attorney-stress-response/
https://en.wikipedia.org/wiki/Cognitive_dissonance
https://www.simplypsychology.org/stress-changes-mixed-emotions-impact-on-health.html
https://www.nature.com/articles/s41598-025-26492-1
