During the first three months of 2024, as the Noto Peninsula in Ishikawa reeled from an earthquake, a Japanese research team did something unprecedented: they tracked the real-time fatigue of thousands of disaster responders as it happened, not months or years later. Using the J-SPEED+ app to collect daily health surveys from disaster workers, Hiroshima University researchers analyzed 15,067 records from 5,569 individuals to understand what actually exhausts the people who save lives in catastrophes.
The findings, published in Safety and Health at Work, matter because fatigued responders cannot think clearly or make sound decisions—a problem that ripples far beyond individual burnout. When disaster workers are worn out, the safety and outcomes of the people they're trying to help suffer too. Yet the well-being of responders has historically taken a back seat to that of affected communities, even though managing responder health is essential to recovery success.
The research team discovered that two factors dominated fatigue levels above all others: the inability to take meals and breaks, and unclear tasks and command structures. This finding echoes previous studies after Japan's 2011 earthquake, when responders reported exhaustion from performing unfamiliar, non-routine work. The 2024 data showed that certain occupational groups struggled most. Logisticians, who made up nearly a third of the surveyed workforce (32.9%), and nurses (29.6%) reported notably higher fatigue than doctors (21.5%). Administrative support staff and those coordinating operations at the Health Emergency Operations Center—who faced high cognitive demands and rapid decision-making about unfamiliar situations—also showed elevated fatigue scores.
The research revealed an encouraging pattern: fatigue decreased over time. During the first response phase (January 1 to February 6), fatigue scores were more scattered, with 73.7% of responders reporting low fatigue levels (scores of 1 to 3 on a 10-point scale). By the second phase (February 6 to March 31), that proportion climbed to 82.3%, suggesting either adaptation to the work or a shift in operational demands. Field staff contributed the most data (65.8%), while those working in coordination centers provided fewer entries—a reflection of where the most intensive labor occurred.
The J-SPEED+ app itself represented a breakthrough in disaster research. Unlike previous studies that relied on memory months after events ended, this system captured responders' actual experiences day by day. The richness of that real-time data—collected across eight categories from work environment problems to symptoms to consultation requests—gives researchers an unprecedented window into the mechanisms of disaster worker fatigue.
Understanding these drivers opens a concrete path forward. If unclear tasks and command structures amplify fatigue, then investing in clearer operational protocols and communication during emergencies could directly improve responder well-being and, by extension, rescue outcomes. Similarly, protecting time for meals and breaks—often deprioritized in crisis mode—emerges not as a luxury but as a crucial performance measure. As natural disasters increase in frequency, the pressure on responders will only grow. Studies like this one offer evidence that protecting their health is not separate from the mission of disaster response—it is central to it.