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Laatikainen-Raussi and colleagues at the University of Jyväskylä and the Finnish Institute of High Performance Sport published this study in Temperature in 2026. Fifty recreationally active adults, 32 men and 18 women, completed four 10-minute sessions in four Finnish saunas with different heaters, with 30 minutes of recovery in between and free löyly after the first 2 minutes. Air temperature and humidity were recorded at six points: at 0.90 metres above the floor, where people sit, and at 1.73 metres, typical head height, each in the middle and on both sides of the room.
Measured against sitting height in the same rooms, head height was both hotter and drier. At 0.90 metres the air averaged 50.8 degrees and 53.8 % relative humidity, at 1.73 metres 69.0 degrees and 27.7 %. Heart rate rose on average by 41.6 beats a minute and core temperature by 0.4 degrees. Temperature and humidity were each associated with the rise, independently of each other: 1.40 beats a minute per degree and 0.37 per point of humidity. How hot a session felt followed mainly the temperature.
The study measured two heights, not individual bench rows, so it gives no temperature for a specific bench. The sessions were short, the four saunas and the amount of water thrown differed, and the measured temperatures were lower than the 73 to 95 degrees usually reported in studies. Most participants were regular sauna users, which the authors say may have shaped how they perceived the heat.
What the data show is a measured difference within one room: where the head is, the air is hotter and drier than where the body sits. They also show that humidity adds strain on its own. They do not rank benches or say where anyone should sit.