How cells sense exercise: A new path to health and energy

For centuries, exercise has been prescribed as a remedy for better health, strength, and mood. We know that physical activity lowers disease risk, improves mental well-being, and boosts longevity.

Yet, what happens deep within our cells during movement has remained largely a mystery. How do cells “feel” exercise? How does that sensation translate into energy, healing, or even pain?

A recent study by scientists at the University of Western Australia and the Perron Institute offers striking new answers.

A new look at exercise and healing

The research, led by Dr. Ziming Chen and Professor Minghao Zheng, shows that cells can feel external forces like stretching and convert them into energy-related responses. This could reshape how we understand exercise and healing.

The researchers found that a mechanical signal travels from the outside of a cell directly into its energy center, the mitochondria, through an organelle called the endoplasmic reticulum (ER). This signal plays a vital role in tissue health and energy regulation.

How cells sense exercise

The endoplasmic reticulum is usually known for building proteins. But in this study, it acts as a sensor that detects stretching or compression caused by movement.

The ER then connects with mitochondria and shares these signals. This interaction controls energy production.

“Cells constantly experience physical forces, especially in load-bearing tissues such as tendon, muscle and lung,” said Dr. Chen.

This signal chain starts with integrins and stretch-sensitive ion channels at the cell membrane. These sensors activate the ER.

The endoplasmic reticulum then transmits the signal to mitochondria through a direct contact zone called the mitochondria-associated ER membrane (MAM). This structure acts like a bridge between the two organelles.

Mechanical forces shape energy production

To test their ideas, researchers built bioreactors that applied gentle strain to human tendon cells.

Advanced imaging revealed that with moderate strain, mitochondria became longer and more active. This shape boosts their ability to produce energy.

However, too much strain caused mitochondria to fragment and malfunction. The ER also swelled and failed to communicate properly with the mitochondria. The paper shows this change triggers stress responses and limits energy production.

“We found that the endoplasmic reticulum plays a central role in converting these mechanical cues into metabolic responses, controlling how cells produce energy and prevent tissue damage,” said Dr. Chen.

How exercise helps or harms cells

The team discovered a “sweet spot” for mechanical stress. At this level, cells respond by enhancing mitochondrial function.

Go beyond this, and cells enter a danger zone. Too much pressure increases ER stress, reduces mitochondrial contact, and causes energy loss.

The study reveals how increasing strain disrupts ER-mitochondria coupling. The cells shift from adaptive energy production to stress response and dysfunction.

“This research has significant implications for understanding how our tendons and ligaments respond to exercise and physical activity,” Professor Zheng said.

Beyond exercise: Broader medical potential

The paper outlines how this mechanism could potentially be beneficial for people who cannot move due to disease.

Treatments could mimic mechanical signals to improve cell function without actual movement. This includes patients with motor neuron disease or muscle atrophy.

The discovery also links mechanical stress to chronic conditions. Misregulated ER-mitochondria coupling may contribute to diseases like asthma, tendinopathy, osteoporosis, and even hypertension.

The study suggests future therapies could target these internal cell bridges.

Why exercise matters for cell repair 

This research demonstrates that cells do not just tolerate movement – they use it to adjust, energize, and repair.

At the core of this process is a mechanical dialogue between the endoplasmic reticulum and mitochondria. When tuned right, this system supports health and prevents injury. When pushed too far, it breaks down.

Exercise, even gentle stretching, now appears to influence the cell in profound and unexpected ways. Physical activity sets off a chain reaction that maintains energy and stability inside the body.

The goal now is to learn how to harness this system for healing, performance, recovery, and disease treatment, especially when traditional exercise is not an option.

The study is published in the journal Science Advances. 

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