It may be getting harder to leave your smart wearable for the sake of your health

The world's first portable electrocardiograph was an 85-pound backpack, and now a 10-gram patch attached to your chest can transmit electrocardiograms uninterrupted for two weeks. The Apple Watch, which is worn by an estimated 100 million people, can send a text message to alert people when their heartbeat is irregular.

Wearable sensors on the arms, wrists and fingers can now report arrhythmias, blood sugar levels, blood oxygen and other health indicators. Medical journals have also proposed a more ambitious vision - wearable devices can monitor patients with chronic diseases, eliminating the need for frequent hospital visits. They can spot potential health problems before a stroke or diabetes develops. The forces of health technology and wearables are converging. Tech giants like Apple (AAPL) and Alphabet's (GOOGL) Google are adding health features to their products. Medical technologists like electrocardiogram patch maker iRhythm Technologies or blood sugar monitor makers DexCom (DXCM) and Abbott Laboratories (ABT) are taking their devices beyond the clinic.

"In the sensor world, people started on the consumer side and wanted to get into health care," said Kevin Sayer, chief executive of Decon Medical. "In health care, we're trying to be more consumer oriented, and I think all of those things are sort of colliding."

Early bets favored the tech giants, with every health-related announcement from Apple, Google or Samsung Electronics hitting medical tech stocks. But changing doctors' practices will also require sustained investment in clinical trials. Big tech companies have cut back on investments in health care. Now it seems that medical technologists will be at the vanguard of the digital health revolution - with smartwatches and smart rings bringing them more customers who need to be diagnosed.

Blake Goodner, co-founder of Bridger Management, a hedge fund focused on health care, said: "A group of medtech companies focused on digital health are maturing and reaching a scale where they can not only be profitable but also make investments to compete with larger tech companies."

Tech giants aren't getting out of the health business. Apple's smartwatch has an electronic heart rate sensor that generates a single-point electrocardiogram, a wrist temperature sensor, and an accelerometer that can detect violent falls. Hundreds of millions of people are wearing smartwatches with health features from Apple or its rivals Samsung and Garmin.