theSIGNAL SCIENCE
27 October 2026
"The body is the soul's first language, and it speaks in asymmetries."
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Science

Exercise Rewires Your Heart's Nerves, Left and Right Differently

Ten weeks of moderate running changed the nerve hubs that steer a rat's heart, and the two sides of the body responded in very different ways.

Here is a strange question: does your heart have a left-handed and a right-handed boss? According to new work from the University of Bristol in the UK, it may well do. The story begins in two small clusters of nerve cells called the stellate ganglia. One sits on each side of the lower neck and upper chest.

They belong to the autonomic nervous system, the autopilot that handles heartbeat, breathing and digestion without asking for your opinion. When your body needs more oxygen, whether you are sprinting for a bus in Nairobi or panicking before an exam in Osaka, these hubs help the heart speed up. Dr. Augusto Coppi and his colleagues wanted to know what regular exercise does to them.

They put rats through 10 weeks of moderate aerobic training, the animal equivalent of steady, sensible cardio. Then they examined the nerve cells themselves. The result was unexpected. Exercise physically remodelled the structure of the neurons, and the changes were dramatically different on the left and the right.

Photo: Isaac Wendland / Unsplash
A runner trains outdoors, the kind of steady aerobic exercise that reshaped heart-controlling nerves in rats.
Discuss
  • Why might evolution have produced nerve clusters on the left and right that respond differently to the same exercise?
  • The study used rats, not people. How much should animal findings shape our expectations about human health?
  • If treatments work better on one side of the body, how should doctors decide where to target therapy?
Science

Why We Can't Quit Psychology's Discredited Classics

Sixty-five percent. That was the share of Yale volunteers who, in Stanley Milgram's early 1960s study, delivered the top "shock" when a man in a lab coat insisted. Critics now call that result misleading, and Philip Zimbardo's 1971 Stanford prison study has been labelled a fraud. So why does Netflix still revive it? Perhaps because the story, not the science, is what survives.…
  • Can a scientifically flawed experiment still teach us something true about human behavior?
∞
These nerve clusters act like the heart's dimmer switch and we've shown that regular, moderate exercise remodels that switch in a side-specific way.
Dr. Augusto Coppi, Senior Lecturer in Veterinary Anatomy, University of Bristol
Science

A Fungus the Size of a Toddler's Arm

Fifty centimetres tall, 2.2 kilograms heavy, and pale as bone: could a fungus like that really have gone unnoticed? In Yunnan, China, researchers found Dianjunus rex rising from the roots of Chinese cork oaks. It is now the largest known fruiting body among the ascomycetes, a group of more than 64,000 species. Its DNA was so unusual that scientists created a whole new family for it, Dianjunaceae.…
  • If a 50-centimetre fungus stayed hidden until now, what else might remain undiscovered?
GLOBAL · Science
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ASIA · Science
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EUROPE · Science
‘It’s magic’: scientists rediscover how to make ancient Roman colour-changing glass
theSIGNAL IN THE LAB
1VOCABULARY
remodelledcaveat
asymmetrydiscreditedfruiting body
implicationsunnoticed
2GRAMMAR FOCUS
Passive voice — full range (simple, continuous, perfect, modal passive)
The passive is formed with a form of 'be' plus the past participle (e.g. 'was found', 'has been labelled', 'is being tested', 'could be explained'). Use it when the action or the thing affected matters more than who performed it.
was · were · has been · is being · could be · have been · must be
  1. The new fungus discovered growing from the roots of Chinese cork oaks in Yunnan.
  2. Zimbardo's 1971 Stanford prison study labelled a fraud by its critics.
  3. In the Bristol experiment, the rats put through 10 weeks of moderate aerobic training.
  4. Some treatments seem to work better on one side, a puzzle that explained by a built-in asymmetry in the nerves.
  5. The nerve cells examined after the training period, and the changes on the left and right turned out to be very different.
  6. Because the research was done in rats, the findings treated with caution before anyone applies them to humans.
3IDIOMS
Define each idiom in your own words. Then write one in a sentence of your own.
  1. hide in plain sight
  2. the story, not the science, is what survives
  3. to rewire (something)
  4. a big caveat
  5. to be a puzzle / to solve the puzzle
4CRITICAL THINKING
Each article ends with a question rather than a conclusion. Why might writers choose to finish a science story on an open question, and does this make the reporting more honest or simply more tempting to click? Choose one article and explain whether its final question adds real value or just creates an impression of mystery.
5CREATIVE · HEADLINES
Write a headline for the top story in each of the following styles. One line each, no explanation:
  • TABLOID NEWSPAPER
  • LUXURY MAGAZINE
  • ACTIVIST BLOG
6WRITING
Choose one of the three discoveries or debates in these articles and write a short paragraph (80-100 words) explaining why the general public should care about it, using at least one idiom from the exercise above.
7DEGREES OF EXTREMITY
Complete each ladder from mild to strong.
  • unexpected→→
  • misleading→→
  • unusual→→
  • noticeable→→
  • puzzling→→
  • large→→
8SPEAKING
  1. Which long-held scientific belief would you most like to see overturned?
  2. Should schools still teach famous experiments that later turned out to be misleading?
  3. Do documentaries about discredited studies do more harm or more good?
  4. What body of knowledge would you trust more: lab results or everyday experience?