Episode 2 was about sleep. But the transcript had no matches for insomnia or camping.[1]
It sounds like a distorted memory of a small study where subjects without sleep disorders slept earlier but not longer or better when camping with natural light and fire only.[2] How long the effect lasted was not studied.
This makes far more sense. A lot of people with insomnia have Sleep Disordered Breathing - sometimes apnea, sometimes UARS which is roughly the same thing except you tend to wake up before oxygen desaturation, resulting in somewhat different symptoms and high false negative diagnostic rates.