Plymfit Study: Feasibility of wrist-worn, commercially available, activity monitor use in perioperative care
This feasibility study demonstrates that using commercially available wrist-worn smartwatches to monitor physical activity in patients undergoing major abdominopelvic surgery is achievable and acceptable, with high data completion rates and patient satisfaction despite some challenges in preoperative adherence and postoperative wear duration.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
Before a major surgery, doctors often face a difficult question: how well will this specific patient's body handle the physical stress of the operation? For years, the standard way to answer this has been to ask patients to exercise on a stationary bike or treadmill while wearing masks to measure their breathing and heart rate. This test, known as cardiopulmonary exercise testing, helps doctors predict who might struggle to recover. However, these tests are expensive, require specialized equipment, and can be hard for older or sicker patients to complete. In recent years, a new idea has emerged: could the simple step counters found on everyday wristwatches provide a similar picture of a patient's fitness without the need for a lab visit? These devices track how much a person moves in their daily life, and scientists suspect that a person's usual activity level might reveal just as much about their health as a formal medical test.
A team of researchers in the United Kingdom decided to put this idea to the test in a real-world setting. They wanted to see if it was practical to ask patients preparing for major abdominal or pelvic surgery to wear a commercial smartwatch for several weeks. The goal was not just to see if the watches worked, but to understand if patients would actually wear them, if the data collected was useful, and if the technology could eventually help doctors guide patients to get fitter before their operation. The study focused on fifty patients scheduled for significant surgeries, such as liver resections or bowel operations, at a single hospital. These patients were asked to wear a Garmin Vivofit 4, a common, battery-efficient watch available in stores, for two weeks before their surgery and for four weeks after. The researchers tracked whether the patients wore the device consistently, how many steps they took, and how their recovery compared to their pre-surgery activity levels.
The results showed that the approach was largely successful. Out of seventy-five eligible patients, the team managed to recruit fifty, a rate that met their target for moving forward with larger studies. Most patients were willing to participate, and the majority of the data collected was complete. However, the researchers found that getting patients to wear the watch every single day before surgery was a bit harder than hoped. About two-thirds of the participants managed to wear the device for at least seven consecutive days before their operation, a figure that fell just short of the ideal target. Despite this, the data that was collected told a clear story. Before surgery, the patients who successfully wore the watch took a median of 5,406 steps per day. Once the surgery was over, their activity levels dropped sharply, with the average person taking only 627 steps in the first week. But as the weeks passed, the numbers climbed steadily. By the fourth week after surgery, the median daily step count had recovered to 3,420, showing a clear pattern of gradual return to normal life.
The study also looked at whether the watch data matched up with the more complex medical fitness tests. While the connection was not perfect, the researchers noticed a trend: patients who took fewer than 4,000 steps a day before surgery tended to have lower scores on their formal fitness tests compared to those who took more steps. This suggests that the simple step count might be a useful, low-cost way to spot patients who are less fit and might need extra support. Perhaps most encouraging was the feedback from the patients themselves. When asked about their experience, most found the watch comfortable and easy to use. A significant majority said that seeing their own step count would help them reach a target number of steps in the future, and many felt that having a medical team review their activity data would make them feel safer and more motivated to move around.
The researchers concluded that using these off-the-shelf watches to monitor patients before and after surgery is both possible and acceptable. The study did not prove that the watches can replace the complex medical tests entirely, nor did it claim that the technology is a perfect predictor of every outcome. Instead, it demonstrated that the method works well enough to justify larger, more detailed studies. The data collected here provides a foundation for future research to determine if tracking daily steps can truly help doctors predict who will have a difficult recovery and if it can guide patients to improve their fitness before they ever enter the operating room. For now, the study confirms that a simple wristband can capture a meaningful picture of a patient's journey through surgery, offering a new tool that is accessible, affordable, and ready for further exploration.
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