Abstract: Techniques for quantifying respiration using a wearable device are described. According to some aspects, a wearable device includes multiple thermal sensors thermally coupled to one or more heat spreaders. The wearable device may in some cases be small enough to be wearable between the mouth and nose of the patient, such as via an adhesive attachment to the upper lip. When the patient exhales, air is produced through the mouth and/or through the nose. Each heat spreader may absorb heat of exhaled air which may thermally propagate to a thermal sensor coupled to the heat spreader. By measuring the change in temperature over time measured by the thermal sensors, measures of respiration such as respiratory rate, minute volume and/or tidal volume of the patient may be determined. Such measures may be determined by the wearable device or by an external device to which data is transmitted.