You're constantly feeling stressed out but there's no way to prove or quantify it? Then this mini stress meter Professor Nitta from the Tokyo Metropolitan University has developed might do the trick for you. The device is basically a pulse-wave sensor and a modified computer mouse rolled into one.
The way it works is that users place their finger on the mouse for 10 seconds, let the meter measures stress by analyzing the blood flow in the user's fingertip and then let the system analyze the variation. The stress level is displayed on a computer screen in real-time on a four level scale.
Regarding the definition of the term “stress”, professor Nitta explains:
You may wonder if what we're measuring is really stress. In this regard, the clearest indicator of stress is the amount of hormones in the blood. Data from such blood analysis has about a 70% correlation with the results of our software. So it's probably fair to interpret this measurement as an indicator of stress, like a blood test.
This video, shot by Diginfo TV (in English), provides more insight:
Via Japan Probe