I'd say at 6 months you're going to still see swings in their natural body cycles at that age. (parenting.stackexchange.com)
Ideally, body temperature drops naturally in the evening so by lowering the temperature in your bedroom you support this natural body cycle. (drjockers.com)
«The nasal cycle, which is part of an overall body cycle, is controlled by the hypothalamus. (breathing.com)