Cortisol is not a “stress hormone”. It’s an energy hormone. It’s the reason you wake up from sleep. A big peak in cortisol in the first 60min after waking is healthy & stimulates elevated energy, mood & focus all day… & LOW cortisol at night (what you want at night). View bright light, ideally from sunlight for 10-20min in the first 60min of your morning, or (if you wake pre-sunrise) 10,000Lux artificial light. The energy increase you will experience is significant. Also cortisol stimulating = moderately intense or intense exercise. Surprise: Caffeine does not increase cortisol much, nor does deliberate cold. Both will extend its action a bit. It takes very little short wavelength light viewed 1-2hrs before sleep to alter your melatonin levels & next morning cortisol & blood glucose, even if you sleep “well”. Adjust accordingly,