Introduction: Risk patients admitted to hospital wards may quickly develop heamodynamic deterioration and early recognition has high priority to allow preventive intervention. The peripheral perfusion index (PPI) may be an indicator of circulatory distress by assessing peripheral perfusion non‐invasively from photoplethysmography. We aimed to describe the characteristics of PPI in hospitalised patients since this is not well studied. Materials and methods: Patients admitted due to either acute exacerbation of chronic obstructive pulmonary disease (AECOPD) or after major abdominal cancer surgery were included in this study. Patients were monitored continuously up to 96 hours with a pulse oximeter. Comparisons between median PPI each day, time of day and admission type were described with mean difference (MD) and analysed using Wilcoxon rank sum test and related to morbidity and mortality. Results: PPI data from 291 patients were recorded for a total of 9,279 hours. Median PPI fell from 1.4 (inter quartile range, IQR 0.9‐2.3) on day 1 to 1.0 (IQR 0.6‐1.6) on day 4. Significant differences occurred between PPI day vs. evening (MD=0.18, 95% CI 0.16‐0.20, P=0.028), day vs. night (MD=0.56, 95% CI 0.49‐0.62, p<0.0001) and evening vs. night (MD=0.38, 95% CI 0.33‐0.42, p=0.002). No significant difference in median PPI between AECOPD and surgical patients was found (MD=0.15, 95% CI ‐0.08‐0.38, p=0.62). Conclusion:Lower PPI during daytime vs. evening and night‐time were seen for both populations. The highest frequency of serious adverse events and mortality was seen among patients with low median PPI. The clinical impact of PPI monitoring needs further confirmation.