S2Y HOT ROOM

At Set2 Yoga we uphold the fundamental principles of Bikram Yoga (BY) as designed by the founder Bikram Choudhury. All BY studios are independent small businesses and not franchised to any global entity. We firmly stick to the original standards because it is the most effective. The requirement for a BY studio is to offer a room for group yoga sessions, outfitted with mirrors, carpets, heating equipment, sufficient humidification and clean air - ventilation.

HEAT

The most important element of the BY studio, of course. The room temperature should be heated to 40 degrees Celsius and have 40-60% humidity. Ideally you do not want to feel the heat on your skin because you will be increasing your internal body temperature to 40 degrees through movement - doing the asanas. Warning - if you consistently practicing in higher than required temperatures, in other words, a temperature range that you can feel on your skin throughout class, you may be at risk of creating long term harm to yourself. You are exposing yourself to heat exhaustion which is more harmful to your body over time, especially the heart.
The medical term for an exceptionally high fever, often considered an emergency, is hyperpyrexia. It typically refers to a body temperature exceeding 41.5 degrees Celsius. You cannot function properly at all. In BY we never enter this zone.

The external heat is most important to sustain the slightly elevated internal body heat. Your internal heat will rise only by +- 1 degree Celsius during practice by which time you are sweating profusely. Sweat cools the body. When the external heat is equal to internal heat you will constantly sweat. It's the most effective purifying routine for the whole body. At the same time you are building fitness, strength, balance and flexibility.

FLOORING

Anything apart from carpet or rubber, is a slip hazard and the surface tends to be too hard. Ideally you want a little spring and cushioning for floor covering in the hot room. We researched and identified the most ideal carpet option that offers the best grip for bare sweaty feet, is impermeable to protect the wooden substrate floor, can be cleaned often, easily replaced if need be, and offers that slight spring and cushion effect.

HUMIDITY

Dry heat stings the lungs, wet air limits oxygen intake. You want to have a comfortable range where breathing is easy in a resting position, standing still or lying down. It should not be strained and you don't want to put too much effort into it, otherwise anxiety shoots right up.
When you exert yourself your heart rate increases and the lungs work harder. The moment you go into a resting position, get out of the posture, all systems disengage and return to normal. So, if you were a car, you are revving the engine, pedal down, and then releasing it to settle back down to idle. This is the best way to build fitness. Pumping 110% non-stop for 45min is a huge strain on all systems, and unsustainable long term.

VENTILATION

Air flow. We have a fan in the centre of the room to push air around and a ventilation system to extract wet air. Without these, you have a cloud of hot, wet air from the waist up; not good for survival. On hot, humid days it is much harder to control air quality, and the teacher will open the doors and/or windows, whatever is needed to allow a breeze through the room. The open door policy doesn't mean we want to cool the room, we want to freshen the air to keep you safe. The temperature will most likely drop a few degrees, but it will just as quickly rise to the setpoint again as soon as the doors and windows are closed. A teacher who is worth their weight in gold has great intuition to keep you safe and will appropriately create extra air flow when needed. Of course, it this is subjective material, so exercising restraint and patience for short periods in class may be required.

Fig 1.
A screenshot of a typical classes at S2Y. This data was taken on 07/03/2025 at 11:54am off the S2Y hot room environment system. It shows class conditions for the 5:30pm to 7pm, 6am to 7:30am and 9:45am to 11:15am classes. The system keeps a constant heat (green line) and regulates humidity (orange line) perfectly. The lowest temperature during the example classes dipped down to 38.9 degrees Celsius and the highest temperature reached was 41.7 degrees Celsius. These temperatures were held for no more than 5 minutes at a time. The dewpoint (yellow) can be considered your "comfort" indicator. A safe range is between 23.8 and 30, anything higher for long periods is reckless and dangerous.