Eight Sleep—often called Silicon Valley’s favorite bed—is like a full-body Fitbit. It is a $3,050 mattress cover filled with sensors to monitor heart rate and body temperature. For people who pay $199 to $399 for an annual subscription, the cover will automatically heat and cool itself throughout the night to keep the owner at a sleep-optimal temperature. The add-on base (about $2,000) raises the angle of the bed to make reading more comfortable or to help stop snoring. Eight Sleep gently vibrates its users awake; it lulls them to sleep with “deep rest” meditations narrated by the wellness-science podcaster Andrew Huberman. To buy the Eight Sleep is to buy fully, with your whole body, into the idea that the future of sleep is technological.

On Monday, the future glitched. Eight Sleep’s fe

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