Among the elderly, falls, mainly caused by orthostatic hypotension, neurological issues, and physical disability, are a significant concern. Photoplethysmography (PPG) is a well-known, non-invasive optical technique that measures variations in blood volume in peripheral tissues. By assessing physiological features related to orthostatic stress, PPG may aid in the detection of postural changes and prevent unsupervised ambulation. This study aims to explore PPG use for postural change detection, identifying gaps, and future challenges. A review was conducted in PubMed, Scopus, and manual bibliography review from its inception until 2025 to identify articles that met our inclusion criteria. No restrictions were applied regarding language or publication date. However, inclusion and exclusion criteria were defined to ensure the relevance and focus of the selected studies. Sixteen studies matched the screening criteria. Two studies included patients with comorbidities. The mean age among the studies was 19.75; two studies included subjects over 60 years old, and the majority of participants in all studies were male. No study included patients with different skin colors. Eight studies used Pulse Arrival Time or Pulse Transit Time as a discriminant marker of postural changes. Five studies were based on the PPG’s wave morphology. The studies were heterogeneous, including different populations, devices, sensors, and methodologies. This review highlights the need for further studies, including on the elderly population, while noting the absence of data validation and measurement guidelines. Despite the challenges, PPG remains a promising technology for assessing unassisted positional change among physically vulnerable populations.