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Vigorous exercise may briefly harm muscle cells, a study finds

12 Mar 2024 | Exercise | 0 comments

Most movement is good for health. But a recent human study suggests that bouts of very vigorous exercise can, for a short time, make the immune system less effective. This matters for people who push hard at work or sport, like firefighters or endurance athletes. In this article we explain what the research found, what “leaky gut” during hard exercise means, and how to train smart while keeping the many benefits of exercise.

Vigorous exercise and the immune system: what the new study found

Evidence type and key result

A peer‑reviewed human experiment tracked 11 young wildland firefighters who did a 45‑minute, intense outdoor workout while wearing full gear. Researchers sampled blood, saliva, and urine before and after and measured thousands of molecules using “multi‑omics,” a lab approach that maps proteins, lipids, and metabolites. After the workout, the firefighters showed signs of tissue stress and repair, and a pattern in saliva of fewer pro‑inflammatory cytokines but more antimicrobial peptides, alongside a literature review that links hard efforts with a higher short‑term risk of respiratory infections. The authors conclude that very intense work may create a brief window of lowered immune defense and advise extra caution around respiratory bugs for people in highly physical jobs (Military Medical Research, 2023).

How could hard exercise lower defenses for a while?

When we push near our limits, body heat, stress hormones, and blood flow shifts help power the effort, but they can also divert resources away from the gut and immune system. Reviews in exercise immunology describe a short “open window” after long or very hard sessions when some white‑blood‑cell functions dip, which may let viruses or bacteria get a foothold (2018 review in Exercise Immunology).

Leaky gut during hard efforts: what it is and why it matters

Leaky gut definition

“Leaky gut” in this context means the intestinal barrier becomes more permeable. Tight junctions between gut cells loosen under heat, low blood flow, and mechanical stress. This can let small amounts of bacterial components (like endotoxin) enter the blood and trigger an immune response.

Evidence in athletes and hot conditions

A synthesis of studies reports that vigorous endurance work for ≥60 minutes at ≥70% capacity—especially in heat, at altitude, or when dehydrated—can raise gut permeability and mild endotoxemia signs (2021 overview; 2022 review). New 2025 work also indicates that heat stress during exercise can affect both paracellular and transcellular gut pathways (2025 study).

What this means for sickness risk

The firefighter paper also reviewed past field studies and found more respiratory symptoms in the days after marathons and military‑style training than in matched controls. That does not prove cause and effect, but it supports the idea of short‑term vulnerability after very hard efforts (Military Medical Research, 2023).

How much is too much? Practical guardrails for training

Keep most sessions moderate

For general health and fat loss, most people do well with regular walking and strength work. Gentle daily movement is easier to repeat and lowers injury risk. See our overview on why walking is the simplest way to lose fat and why after 40, lifting weights slows muscle loss.

Taper intensity and plan recovery

According to those information (not medical advice – you need to double check), if you love hard workouts:

  • Limit very hard sessions to 2–3 times per week, spaced out.
  • Add cooling, fluids, and shade in hot weather; plan the hardest efforts in cooler hours.
  • Refuel with carbs and fluids soon after long or hot sessions.
  • Sleep 7–9 hours; schedule an easier day after races or heat exposure.
  • Avoid crowded indoor spaces right after an extreme effort, when you may be in that short “open window.”

Watch for warning signs

Take a lighter day if you notice: unusual fatigue, gut cramps during training, reduced appetite, rising morning heart rate, or frequent colds.

Limitations and quality of evidence

  • The firefighter study is small (n = 11, male) and measures biomarkers, not infections directly. It suggests mechanisms and risk, not proof of disease.
  • Exercise overall reduces long‑term illness risk; most data showing a brief dip in defenses follow very hard or long efforts, often with heat or dehydration.
  • Some experts argue the infection risk after exercise is lower than once thought, so context matters (2018 review).

Bottom line

Keep moving, exercise is one of the best tools for health. If you push very hard, especially in heat, plan recovery and hygiene for the next 3–24 hours. That helps keep the gains while lowering any short‑term immune dip.

Military Medical Research – Elucidating regulatory processes of intense physical activity by multi‑omics analysis – 2023

A human multi‑omics study in wildland firefighters found biomarker patterns after a 45‑minute intense workout that suggest a brief dip in immune defense and reviewed past studies linking hard efforts to more respiratory symptoms (the peer‑reviewed paper). Evidence type: human experiment; funding: US agencies including PNNL and CDC NIOSH (see paper disclosures).

Exercise Immunology Review – Debunking the myth of exercise‑induced immune suppression: redefining the impact of exercise on immunological health – 2018

This influential review argues that routine exercise supports immunity and that infection risk after exercise is often overstated, while acknowledging transient post‑exercise changes in some immune measures (review article). Evidence type: narrative review.

Frontiers in Physiology – Gastrointestinal function and microbiota in endurance athletes – 2025

A minireview outlines how hard endurance work and environmental heat stress the gut barrier and discusses strategies to optimize GI function for athletes (minireview). Evidence type: narrative review.

Disclaimer: The information shared here is for awareness only. Review the provided sources, cross-check with other trusted references, and talk about it with qualified healthcare professionals before making any medical decision.

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Listening is the underrated skill that makes you a better leader instantly

25 Nov 2025 | ,

We often think of great leaders as great talkers. We imagine them giving rousing speeches, setting a clear vision, and having an answer for everything. But a massive review of scientific research suggests we have it backward. The most effective way to improve your leadership isn’t to speak more; it is to listen better.

New data shows that listening is not just a “soft skill” for making friends – it is a hard driver of job performance and professional success.

144 studies confirm listening drives performance

A recent meta-analysis published in the Journal of Business and Psychology examined the link between listening and work outcomes. The researchers looked at data from 144 studies involving more than 155,000 people.

Their conclusion was clear: listening has a strong, positive effect on employee job performance.

Leaders who are perceived as good listeners do more than just make their employees feel warm and fuzzy. They actually get better results. The study found that listening improves the quality of relationships at work, which in turn boosts performance. When employees feel heard, they perform better. This dynamic helps leaders unlearn bias and lower conflict within teams.

As the researchers noted, the link between listening and positive job outcomes is “robust.” They suggest that listening is an underrated predictor of job performance – a simple cause of superior results that many organizations overlook.

Why we love to talk about ourselves

If listening is so effective, why is it so hard? Why do so many of us default to talking instead?

The answer lies in our biology. A study published in the Proceedings of the National Academy of Sciences (PNAS) found that talking about ourselves is inherently rewarding. In fact, humans devote about 30–40 percent of everyday speech to informing others about their own subjective experiences – their thoughts, feelings, and opinions.

Using brain scans, researchers found that self-disclosure activates the mesolimbic dopamine system – the same brain regions associated with the pleasure we get from food, money, and sex. It feels good to talk about yourself.

The drive is so strong that people in the study were willing to give up money just to keep talking about themselves. When given a choice between answering questions about others for a higher payment or answering questions about themselves for a lower payment, participants voluntarily gave up between 17 and 25 percent of their potential earnings to talk about their own views.

We are wired to broadcast. To lead effectively, you have to fight that wiring.

The power of follow-up questions

You can become a better listener instantly by changing how you ask questions. It is not enough to just stay silent; you need to show you are engaged.

Research published in the Journal of Personality and Social Psychology found that the specific type of question you ask matters. The study showed that asking follow-up questions – questions that ask for more detail on what the other person just said – dramatically increases how likable you appear.

When you ask a follow-up question, you prove you were listening. You signal validation, care, and understanding. This simple habit makes you more persuasive and influential because, as other research in Frontiers in Psychology shows, likable people are better at influencing those around them.

Asking follow-up questions and recalling small details are among seven habits that mark an exceptional listener, and this research confirms it is a key tool for leaders.

Feeling known leads to feeling supported

Listening does more than build rapport; it meets a fundamental human need.

A study in the Journal of Personality and Social Psychology found that employees feel less objectified when their boss knows them as people, rather than just as workers or numbers. Furthermore, research linked to the Journal of Experimental Psychology suggests that “feeling known” is a necessary precursor to “feeling supported.”

You cannot support an employee you do not know. You cannot help them reach their career goals if you never asked what those goals were. You cannot solve their roadblocks if you never listened to what those roadblocks are.

What you can do about it

To become a better leader today, flip the ratio of your conversations.

  • Talk less. Recognize that your brain wants the dopamine hit of talking about yourself. Resist it.
  • Ask for their story, not yours. Instead of telling your team about your weekend or your problems, ask about theirs.
  • Use the follow-up rule. When an employee answers, do not just nod and move on. Restate what they said or ask one follow-up question based on what they just said.
  • Listen to learn. You already know what you know. The only way to learn something new is to listen to what others know.

Mastering conversation: how active listening keeps dialogue engaging is a skill you can practice in every interaction, whether with a colleague, a client, or a friend.

Sources & related information

Journal of Business and Psychology – The Power of Listening at Work – 2023

A meta-analysis of 144 studies involving 155,000 observations found that perceived listening is strongly correlated with improved job performance and relationship quality.

Proceedings of the National Academy of Sciences – Disclosing information about the self is intrinsically rewarding – 2012

Neuroimaging research shows that self-disclosure activates the brain’s reward systems, motivating people to talk about themselves even at a financial cost.

Journal of Personality and Social Psychology – It Doesn’t Hurt to Ask – 2017

A series of studies demonstrates that asking follow-up questions increases interpersonal liking by signaling responsiveness and listening.

The Pratfall Effect: why making mistakes can make you more likable

23 Nov 2025 | ,

Perfection is often overrated. While we strive to be flawless in job interviews or first dates, psychology suggests that being too perfect can actually push people away. A small blunder, like tripping or spilling a drink, might do more for your popularity than a flawless performance. This phenomenon is known as the Pratfall Effect.

What is the Pratfall Effect?

The Pratfall Effect is a psychological principle that states that a person’s likability increases when they make a clumsy mistake, but only if that person is already perceived as competent.

Social psychologist Elliot Aronson first identified this effect in 1966. He wanted to test how mistakes influence attraction. In his famous experiment, he asked male college students to listen to tape recordings of people answering quiz questions.

The participants heard one of two main scenarios:

  1. The Superior Person: This person answered 92% of the questions correctly. They sounded confident and knowledgeable.
  2. The Average Person: This person answered only 30% of the questions correctly.

Aronson then added a twist. In some recordings, the “Superior Person” commits a blunder at the end: they are heard spilling a cup of coffee and reacting to the mess.

The results were clear. The students rated the Superior Person who spilled the coffee as the most likable of all. The blunder made the highly competent person seem more human and approachable.

The catch: competence is key

There is a crucial condition to this effect. A mistake only helps you if you have already established your competence.

In Aronson’s experiment, when the “Average Person” (who missed most quiz questions) spilled the coffee, their likability rating dropped even further.

  • If you are competent: A mistake humanizes you. It breaks the “too good to be true” barrier and prevents others from feeling threatened by your perfection.
  • If you are incompetent: A mistake just reinforces the idea that you are not capable. It acts as proof of inadequacy.

This distinction is vital. You cannot simply be clumsy and expect to be popular. You must first demonstrate that you are good at what you do. The blunder acts as a softener for your competence, not a substitute for it.

Real-world examples: from Jennifer Lawrence to brands

We see the Pratfall Effect in action in celebrity culture and marketing.

The relatable celebrity

Jennifer Lawrence is often cited as a modern example. Her frequent trips on the red carpet or candid, unpolished interviews often endear her to the public. Because she is an Oscar-winning, highly successful actress (high competence), these slips make her seem “down to earth” rather than clumsy.

The honest brand

Marketing experts use a similar concept known as the “blemishing effect.” When a brand admits a small flaw, consumers often trust it more. For example, Guinness: the beer brand famously turned a negative – the long time it takes to pour a pint – into a legendary slogan: “Good things come to those who wait.”

Why perfectionism harms connection

The Pratfall Effect challenges the idea that we must hide our flaws to be accepted. In social situations, perfection creates distance. We often struggle to connect with someone who seems to have no weaknesses because we cannot relate to them. This relates to understanding conversational biases to become more likable, where showing genuine engagement often matters more than saying the perfect thing.

When a competent person slips up, it levels the playing field. It signals vulnerability. This vulnerability fosters trust and signals that the person is authentic, not a curated persona.

What you can do about it

You do not need to stage accidents or spill coffee on purpose. However, you can change how you react to your own errors.

  • Don’t hide every flaw: If you are good at your job, admitting a small error or a gap in knowledge can make you more approachable to your team.
  • Own your blunders: When you trip or misspeak, laugh it off. Trying to cover it up often looks worse than the mistake itself.
  • Build competence first: Remember that this effect relies on a foundation of skill. Focus on being capable and reliable first.
  • Accept imperfection in others: Just as your mistakes humanize you, seeing others stumble is a reminder that everyone is human. This perspective can help reduce judgment and social anxiety.

Sources & related information

Elliot Aronson – The Effect of a Pratfall on Increasing Interpersonal Attractiveness – 1966

The original study published in Psychonomic Science where Aronson and his colleagues demonstrated that a blunder increases the attractiveness of a superior person but decreases the attractiveness of a mediocre person.

The Guardian (ZenithOptimedia) – The Pratfall effect and why brands should flaunt their flaws – 2015

An analysis of how brands like Guinness and VW use the Pratfall Effect to build trust by admitting minor weaknesses, making their core claims more believable.

Journal of Consumer Research – The blemishing effect – 2012

Research showing that under certain processing conditions, a small amount of negative information can actually enhance the positive impression of a product.

https://www.youtube.com/watch?v=traKGc2NDWQ

Endmyopia claims to reverse nearsightedness naturally (but science remains skeptical)

23 Nov 2025 |

Imagine never needing your glasses again. No surgery, no contacts, just… fixing your eyes yourself. That’s the big promise of Endmyopia, a popular online method created by Jake Steiner. He claims you can reverse nearsightedness (myopia) just by changing your habits.

It sounds awesome, right? But before you throw away your glasses, you need to know that most eye doctors and scientists say it’s not that simple. Here is the lowdown on what this method is, why people try it, and why the medical consensus says it probably won’t work like you think.

The big claim: “Your glasses are the problem”

Endmyopia is based on a simple idea: your eyes aren’t broken; they are just reacting to your environment.

It starts with a muscle cramp

The theory goes like this: when you spend hours staring at your phone or laptop, a focusing muscle inside your eye gets tired and cramps up. This is called pseudo-myopia. At first, your vision is only blurry because of this cramp.

Then your eye grows longer

The controversial part is what happens next. Steiner says that when you wear glasses to fix that blur, your eye physically grows longer to “adapt” to the lenses. A longer eyeball is what causes true nearsightedness. Basically, the method claims your glasses trap you in a cycle that makes your vision worse.

The “fix”: training your eyes

To reverse this, Endmyopia tells you to do two things:

  1. Use weaker glasses: Instead of your full prescription, you wear weaker glasses for close-up work (like homework or gaming) to stop the eye strain.
  2. Practice “Active Focus”: This is a mental trick. You look at something far away that is slightly blurry (like a street sign) and try hard to make it clear just by focusing. The idea is that this effort forces your eyeball to shrink back to its normal size.

What science says

Here is the problem: Eye doctors agree that once your eyeball grows too long, it usually stays that way. It’s like your height – once you grow tall, you don’t shrink back down just because you want to.

Your eyeballs aren’t like muscles

You can train a muscle to get bigger, but you can’t really train an eyeball to get shorter. While atropine drops or special contact lenses can slow down eye growth in kids, there is no scientific proof that you can reverse it significantly once it’s happened.

Wearing weak glasses might backfire

Trying to fix your eyes by wearing weaker glasses can actually make things worse. A famous study (Chung et al., 2002) showed that under-correcting vision (wearing glasses that are too weak) made kids’ eyes grow faster, not slower. Blurry vision seems to signal the eye to keep growing, which is the exact opposite of what you want.

Why do some people swear it works?

If science says it doesn’t work, why are there so many success stories online? Read on Reddit: I was able to effectively fully cure myopia with my own methodology of eye exercises and discussions about do eye exercise really work?.

Brain training vs. Eye shrinking

When you practice looking at blurry things, your brain gets smarter at guessing what it’s seeing. This is called blur adaptation. You might be able to read a sign further away, not because your eyes are fixed, but because your brain is better at decoding the fuzzy image. You are “seeing” better, but your nearsightedness hasn’t actually disappeared.

Is there any hope?

Interestingly, some new research on red light therapy shows that specific light treatments might slightly shorten the eye.

Is it worth trying?

Trying to fix your eyes this way takes a huge amount of time – years of daily practice. Walking around (or driving!) with blurry vision can be dangerous.

Sources & related information

Study: Weak glasses make eyes worse (2002)

A major study showed that giving kids weaker glasses actually made their nearsightedness get worse faster.

Experts: Can you reverse myopia?

Eye doctors explain that while eye spasms can be fixed, the actual shape of a nearsighted eye is permanent.

Endmyopia Website

The source of the “active focus” method and the theory that glasses are to blame.

Red Light Therapy Study (2022)

A study showing that a specific type of red light therapy could shrink the eye slightly, proving some change is possible.