<![CDATA[Abstract. Shift work systems in industries operating 24 hours, such as limestone factories, have the potential to cause work fatigue due to misalignment with circadian rhythms, particularly during night shifts. Work fatigue is an important risk factor for decreased work performance and occupational safety. This study aimed to analyze differences in work fatigue levels based on work shifts among workers at limestone factory X. A descriptive-analytic study with a cross-sectional design was conducted among 42 blue-collar workers in the production division, consisting of 22 morning-shift workers and 20 night-shift workers. Work fatigue levels were measured using the Subjective Self Rating Test (SSRT) questionnaire. Statistical analysis was performed using the Mann–Whitney test. In the morning shift, low and moderate fatigue were equally distributed (50%), whereas the night shift was predominantly characterized by moderate (70%) and high (30%) fatigue levels. A significant difference in work fatigue levels was found between morning and night shifts (p < 0.001), with higher fatigue observed among night-shift workers. Night shift work is associated with higher levels of work fatigue compared to morning shifts. These findings highlight the importance of effective shift work management to prevent increased fatigue among night-shift workers.Abstrak. Sistem sif kerja pada industri yang beroperasi 24 jam, seperti pabrik kapur, berpotensi menimbulkan kelelahan kerja akibat ketidaksesuaian dengan irama sirkadian, terutama pada sif malam. Kelelahan kerja merupakan faktor risiko penting terhadap penurunan kinerja dan keselamatan kerja. Penelitian ini bertujuan menganalisis perbedaan tingkat kelelahan kerja berdasarkan sif kerja pada pekerja pabrik kapur X. Penelitian deskriptif analitik dengan desain cross-sectional dilakukan pada 42 pekerja blue-collar divisi produksi, terdiri dari 22 pekerja sif pagi dan 20 pekerja sif malam. Tingkat kelelahan kerja diukur menggunakan kuesioner Subjective Self Rating Test (SSRT). Analisis statistik menggunakan uji Mann–Whitney. Pada sif pagi, kelelahan rendah dan sedang memiliki proporsi yang sama (50%), sedangkan pada sif malam didominasi kelelahan sedang (70%) dan tinggi (30%). Terdapat perbedaan tingkat kelelahan kerja antara sif pagi dan sif malam (p < 0,001) yang menunjukan tingkat kelelahan lebih tinggi pada sif malam. Sif kerja malam berhubungan dengan tingkat kelelahan kerja yang lebih tinggi dibandingkan sif pagi. Temuan ini memperlihatkan pentingnya pengelolaan sif kerja untuk mencegah kelelahan yang lebih tinggi pada pekerja sif malam.]]>
