Fast and activating

Tummo: the inner fire that dried wet sheets in the Himalayas

By GyroscopeUpdated November 15, 202612 sources

Family

Fast and activating

Breaths

Taught in person, built on holds

Carbon dioxide

Falls

How well tested

Weak

Risk

High, read the safety part

Timer

None, on purpose

Tummo, or g-tummo, is the inner fire meditation of Tibetan Buddhism. Practitioners hold the breath with the belly drawn in, breathe either hard or softly around that hold, and picture heat rising inside the body. In a 2013 study, expert meditators raised their core temperature into a mild fever this way. We’d treat it as what it is, a lineage teaching you learn from a teacher, with the same safety rules as any forceful breathing and long holds.

Tummo’s fame rests on one picture. Monks sit in freezing air with cold, wet sheets over their bare shoulders, and the sheets steam and dry. It’s a real ceremony, and Harvard researchers filmed one in 1985. Online, that picture has turned tummo into a superpower you can pick up from a video, or into an older name for Wim Hof breathing.

The sheets prove less than they seem to. The 2013 researchers pointed out that wet cloth will steam and dry on any warm body in freezing air, so a dry sheet doesn’t show a high temperature. And the experts they studied had spent years on retreat, learning from teachers who keep the details between teacher and student.

What it is and where it comes from

Tummo literally means inner fire. Judith Simmer-Brown, a professor at Naropa University and a senior Buddhist teacher, describes it as yogically generated “fierce inner heat”. It’s one of the Six Yogas of Naropa, and teachers consider it the foundation for the other five. It came out of medieval Indian tantric communities about a thousand years ago. The teacher Tilopa passed it to his student Naropa, Naropa passed it to Marpa, who carried it from India to Tibet, and Marpa passed it to his student Milarepa.

Teachers say the heat is a side effect. Milarepa warned students against mistaking the trunk of the tree for its fruit. In their telling, breath and visualization move energy through channels in a subtle body, toward bliss and a wiser kind of awareness. The 2013 researchers call it one of the most sacred practices in Vajrayana Buddhism and the Bon tradition.

Western science arrived through Herbert Benson of Harvard. The Dalai Lama visited Harvard in 1979 and agreed to help him study meditating monks in northern India. In 1982 Benson’s team reported in Nature that during tummo, three monks warmed their fingers and toes by up to 8.3 C (about 15 F), while their core temperature didn’t change. A 2002 Harvard Gazette story describes monks in a 40 F room drying sheets soaked in 49 F water, each sheet in about an hour. In February 1985, Benson’s team watched monks sleep on a rock ledge 15,000 feet up in the Himalayas at 0 F, in wool or cotton shawls, with no sign of shivering.

Then in 2013, psychologist Maria Kozhevnikov of the National University of Singapore took thermometers and brain-wave caps to Gebchak nunnery and other monasteries in eastern Tibet. Ten meditators, seven of them women, practiced in rooms that sit around freezing in January.

How to do it

Tummo is taught in person. Simmer-Brown writes that the instructions for the vase breath should come from one’s guru, and that students should already be well grounded in meditation. Practitioners explained the shape of it to the 2013 researchers.

1. Preparation comes first. Teachers expect a solid meditation practice, and prepare students with yogic exercises and with visualizing the body’s subtle channels.
2. The vase breath. After breathing in, practitioners hold the breath and draw in the belly and pelvic floor, so the lower belly takes the shape of a vase.
3. Forceful or gentle. In the forceful kind, the breathing is vigorous and builds heat. In the gentle kind, it’s easy and unstrained and keeps the heat going.
4. The visualization. At the same time, practitioners picture heat or a flame rising through the body.

Any version you try falls under the same rules as fast rounds. Sit on the floor or a bed, never in or near water and never in a car, and stop if you feel dizzy or get chest pain.

A simple way to picture it

Forceful vase breathing is a bit like shivering on purpose. Squeezing big muscles over and over makes heat, the way shivering does, and the visualization is what kept the meditators at it long enough for the heat to build.

What happens in your body

The 2013 researchers found two parts to the warming. The first is the body, where the forceful vase breath, with its hard squeeze of the belly, makes heat. The second is the mind. The visualization let the meditators keep going for longer, and the bigger their rise in alpha brain waves, the bigger their rise in temperature. Without the visualization, both the meditators and a group of Western volunteers could keep up the forceful vase breath for only a short time, and their temperature stayed in the normal range.

Benson’s 1982 numbers measured something different. Warmer fingers and toes are skin temperature, and the 2013 team noted that Benson’s readings went from about 22 C to 33 C, which is still normal for skin. The core didn’t move in his monks, but it did in Kozhevnikov’s experts.

Holding your breath is work for your heart too. In a 2021 study of 20 healthy adults, blood pressure rose during a yogic breath hold, and the amount of blood the heart pumped fell. Forceful breathing that moves more air than you need also blows off carbon dioxide, which can bring tingling, lightheadedness and cramping hands, all listed by MedlinePlus. Carbon dioxide and breath holds have the long version.

What the evidence shows

In Kozhevnikov’s study, armpit temperature rose from normal into a slight or moderate fever, up to 38.3 C (100.9 F), and only during the forceful breath. The four meditators who did only the gentle kind didn’t raise their core temperature, which fits its purpose of holding heat rather than building it. Some experts could keep the forceful practice going for up to 50 minutes, while others managed six or seven.

Her team then taught the vase breath to 11 Westerners with yoga or martial arts experience but no Tibetan training, in a 30-minute session. Without the visualization, their temperature rose a little and topped out at 37.0 C (98.6 F), a normal body temperature.

These four results are close to everything anyone has measured, all from tiny studies. The 2013 team said the sacredness of the practice and the remote monasteries kept their numbers small. We couldn’t find a trial of tummo for any health outcome. The 2013 authors suggested parts of it might help people learn to regulate their temperature, and we couldn’t find anyone who has tested that either.

Who should skip it

• Sitting or lying down only, on the floor, a mat or a bed.
• Never in or near water, including the bath, and never driving. The Wim Hof method warns that its own forceful breathing can make you pass out, and StatPearls notes that blacking out under water can happen at any depth.
• Skip it entirely if you’re pregnant, or have epilepsy, coronary heart disease, a history of heart failure or stroke, high blood pressure you take medicine for, or a recent operation. Tummo’s teachers give instructions in person, so the closest written list is the Wim Hof method’s own, for its related forceful breathing and holds.
• Go easy if your blood pressure runs high, since breath holds push it up.
• Don’t test it in the cold. The nuns at Gebchak walk for hours at minus 25 to minus 30 C in their yearly sheet ceremony, after years of training. The Wim Hof method’s safety page warns that careless cold exposure can cause hypothermia.