Now, the pause button of the human body has been touched

In the dim lab in St. Louis, the mouse is still lying. Its heart slows down, body temperature drops, and its cells have transferred to a low energy state that echoes the wintering bear.

But this is not nature at work, but the hands of scientists. The researchers used tiny wearable ultrasound devices that triggered a torpor-like state in the mouse brain. It is artificial, precise, and most critically reversible.

It’s a synthetic Torpor, a long-imagined physiological pause button that can one day help doctors buy valuable time – after stroke, organ transplant, and even on their way to Mars. A team led by Hong Chen, professor of biomedical engineering and neurosurgery at Washington University in St. Louis, is pioneering the effort. Their method is detailed Natural metabolismusing focused ultrasound to regulate the brain’s hypothalamus, tempting the body to a deep, energy-saving mode without medication, surgery or genetic modification.

Learn from the Survival Artist of Nature

Torpor is common in the animal world. Hummingbirds use it every night to survive the cold air. The bear relies on it to hibernate in the harsh winter. But humans? We have never done it. This has not stopped scientists from trying.

“Comprehensive torpor is no longer just a theoretical concept,” Chen said. “This is an emerging field and it is possible to redefine medicine.”

Chen’s group is the first to demonstrate a non-invasive, reversible method to induce this state in mice and rats. While mice naturally enter Torpor, rats do not – but this technique works in both. This opens the door for future human applications where Torpor can protect the brain and organs by slowing down the body’s metabolic mechanisms rather than trying to recover them.

Calling the body needs

Traditional medicine usually focuses on restoring energy supply – think about rushing to open blocked arteries after a heart attack. Logical synthetic twists and turns: reduce the body’s energy needs and you will give it time to recover. During the induced Torpor, the body temperature of the mice dropped by about 3°C. Heart rate slowed by nearly 50%, and metabolism turned completely to fat burning, reflecting the iconic energy pattern of natural Torpor.

“The ability of synthetic torpors to regulate systemic metabolism is expected to change medicine,” Chen and colleagues wrote in a July 31 viewpoint. Natural metabolism.

Real-world possibilities

These implications go far beyond the lab. In preclinical models, synthetic Torpor has:

• After simulated stroke, brain damage in mice was reduced by 71%
• Organ functions preserved under conditions of hypoblood flow or similar transplant
• Prevent radiation-induced tissue damage
• Bioaging markers slow down in long-term experiments

There is even evidence that induction of Torpor can affect the accumulation of tau protein, a major driver of Alzheimer’s disease and may inhibit tumor growth in some cancer models.

Challenges between mice and Mars

Still, there is no preparation for the clinic or the comprehensive top of the universe. The human body is larger, has slower cooling, and is more complicated than rodents. Past attempts to use compounds such as hydrogen sulfide have encountered dangerous side effects. But ultrasound may provide a safer route. It has been FDA-approved for other brain therapies and the WASHU team’s approach is completely non-invasive.

Wenbo Wu is a doctoral student at Chen’s Lab, and the recent paper lead author highlights future obstacles: metabolic differences between species, the need for reversible control, and the ethical considerations of using Torpor in intensive care. “The collaboration between scientists, clinicians and ethicists is crucial,” Wu said.

What’s next?

The next frontier involves testing these methods in larger mammals and fine-tuning the balance between central brain control and peripheral metabolic systems. Chen’s team envisions a dual approach: to induce TORPOR using brain stimulation, while also providing medication or regulating nerves outside the brain to safely maintain it.

Science fiction has long imagined this situation: frozen legs, humans preserved for healing or space travel, and that is not lost. The difference now is that it doesn’t seem so far-fetched anymore.

“Realizing this potential not only requires bridging the gap between neuroscience, engineering and medicine, but also creating an inclusive research ecosystem that ensures ongoing funding and a thoughtful dialogue with the public,” Chen wrote.

A new type of emergency medicine

Image: The caregiver placed the device on the forehead of the trauma victim, pressed the button, and purchased two hours of metabolic stillness before the operation. Either use only a small portion of normal oxygen and food, or astronauts heading to Jupiter quietly slide into Torpor. These are not tomorrow’s dreams – they are today’s goals.

It all starts with a mouse, lying quietly in the lab, waiting to wake up.

Magazine: Natural metabolism
doi: 10.1038/S42255-025-01345-3
author: Wenbo Wu, Genshiro A. Sunagawa, Hong Chen

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