Wearable-based health state verification for physical access authorization

A system configured to grant passage through a doorway based on health state, comprising:

• a wearable device comprising:
• a first sensor configured to measure a signal indicative of a photoplethysmogram signal (PPG signal) of a user, and a second sensor configured to measure a temperature of the user;
• and
• a computer configured to:
• receive current measurements of the user, taken with the wearable device;
• receive baseline measurements of the user, taken with the wearable device on one or more earlier days;
• calculate a health score based on a difference between the baseline measurements and the current measurements;
• calculate an extent of similarity between characteristics of the PPG signal in the current measurements and characteristics of the PPG signal in the baseline measurements;
• and
• transmit an authorization signal responsive to the health score reaching a first threshold and the extent of the similarity reaching a second threshold;
• whereby transmission of the authorization signal indicates a health state of the user permits passage through the doorway.