A patient worn sensor assembly for detecting, recording, and communicating patient vital signs includes several structural features that can provide increased signal quality, reduction in signal noise, increased patient comfort, increased reliability, and increased adhesion to a patient's skin. The patient worn sensor can track vital sign information such as blood pressure, body temperature, respiratory rate, blood oxygenation, heart rhythm (via ECG), heart rate, blood glucose level, and hydration (bio-impedance) levels. The sensor can also track and record additional information about patients, including patient movement, activity, and sleep patterns.