Apple is building a team of senior medical technology executives, raising hackles in the biotechnology community and offering a hint of what the iPhone maker may be planning for its widely expected iWatch and other wearable technology.

In the past year, Apple has snapped up at least half a dozen prominent experts in biomedicine, according to LinkedIn profile changes.

Apple has poached biomedical engineers from companies including Vital Connect, Masimo Corp, Sano Intelligence, and O2 MedTech.

Masimo is best known for its pulse oximetry device, which noninvasively measures patients’ oxygen saturation, an indicator of respiratory function. Vital Connect focuses on tracking vitals like heart rate and body temperature. O2 Med Tech also is experimenting with biosensors and developing new devices.