And tips<ref>https://forum.quantifiedself.com/t/tips-for-improving-deep-sleep/3411</ref><ref>https://forum.quantifiedself.com/t/interventions-to-improve-sleep/9599/4</ref> and earplug suggestions<ref>https://forum.quantifiedself.com/t/what-sleeping-earplugs-are-you-using/5342</ref>.