Asian nuclear physicists discovered that what people call Qi/Prana is actually a low-frequency, highly concentrated form of infrared radiation.

In experiments conducted in the 1960s, nuclear physicists in China came to accept the notion that Qi is actually a low-frequency, highly concentrated form of infrared radiation.

This radiation is the euphoric energy that is present when experiencing Frisson, or as the Runner's High, or as the Vibrational State before an Astral Projection, or as Qi in Taoism and in Martial Arts, or as Prana in Hindu philosophy and during an ASMR session.

Researchers have witnessed certain test subjects who were able to consciously emit this form of energy from their bodies.

Here's a Harvard study of the Tibetan people who use this same energy under a different name called Tummo to raise their body temperature. https://www.snopes.com/fact-check/harvard-study-confirms-tibetan-monks-can-raise-body-temperature-with-their-minds

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0058244

And a paper from the CIA website on the accuracy of the Qi(Spiritual chills) and its usage through the eastern practice of Qigong: https://www.cia.gov/readingroom/docs/CIA-RDP96-00792R000300400002-9.pdf

''Chinese scientists, using arrays of modern detectors, tried to monitor emissions originating from qigong masters. They met with partial success by detecting increased levels of infrared radiation. Interestingly, the emission oscillated with a low frequency''

As the Taoist concept of Qi crossed over into the West in recent years, the Western word Bio-electricity was coined to describe it since Chi has a number of properties that seem similar to those of electrical energy.

Eventually, you can learn how to bring up this wave of euphoric energy feel it over your whole body, flooding your being with its natural ecstasy and master it to the point of controlling its duration.

This energy has been researched and documented under many names, by different people and cultures, such as the Runner's High, what's felt during an ASMR session, Bioelectricity, Euphoria, Ecstasy, Voluntary Piloerection (goosebumps), Frisson, the Vibrational State before an Astral Projection, Spiritual Energy, Orgone, Rapture, Tension, Aura, Nen, Odic force, Secret Fire, Tummo, as Qi in Taoism / Martial Arts, as Prana and Vayus in Hindu philosophy, Ihi and Mana in the oceanic cultures, Orenda and Tona in Native American culture, Life force, Intent, Pitī in Buddhist teachings, Aether, Universal Magnetic Fluid Spiritual Chills, Chills from positive events/stimuli, The Tingles, on-demand quickening, Ruah and many more to be discovered hopefully with your help.

• All of those terms detail that this subtle energy activation has been discovered to provide various biological benefits, such as:

Unblocking your lymphatic system/meridians

Feeling euphoric/ecstatic throughout your whole body

Guiding your "Spiritual Chills" anywhere in your body

Controlling your temperature

Giving yourself goosebumps

Dilating your pupils

Regulating your heartbeat

Counteracting stress/anxiety in your body

Internally healing yourself

Accessing your hypothalamus on demand for its many functions

Control your Tensor Tympani muscle

and I was able to experience other usages with it which are more "spiritual" such as:

A confirmation sign

Accurately using your psychic senses (clairvoyance, clairaudience, spirit projection, higher-self guidance, third-eye vision)

Managing your auric field

Manifestation

Energy absorption from any source

Seeing through your eyelids during meditation.

If you are interested in learning to voluntarily feel it anywhere/everywhere, amplify it, increase its duration and even those biological/spiritual usages mentioned above, there are three written tutorials going more in-depth about this subtle "energy", explicitly revealing how you can that you can find on the sub community mentionned at the end.

P.S. Everyone feels it at certain points in their life, some brush it off while others notice that there is something much deeper going on. Those are exactly the people you can find on r / Spiritualchills where they share experiences, knowledge, tips on it.