Aging is a continuous process. Depending on a person's physical, mental, and psychosocial status, various changes in abilities occur, affecting daily activities and participation in society. With age, the likelihood of functional decline and loss of functional abilities increases. However, physical and mental training has been shown to slow this process [1]. Geriatric rehabilitation (GR) is a field of medicine that focuses on preventing and promoting health, focusing on physical functioning and independence in daily life. A second component is rehabilitation after injury or illness, starting in the intensive care unit. Rehabilitation specialists should be part of a multidisciplinary team and that leads the rehabilitation process. GR can help frail older adults maintain independence in long-term care facilities. Understanding the relationships between diseases, pathophysiology, and impaired performance, and individual risks is the basis for rehabilitation planning. The knowledge of training mechanisms, exercise, occupational therapy, and physical therapy, as well as team processes, makes physical therapists experts in GR [2].

Biological age (BA) is defined as an integrative indicator reflecting the degree of organismal aging and biological wear of physiological systems. In contrast to chronological age, BA is a potentially modifiable variable and may serve as a biomarker of geroprotective intervention efficacy. Recent advances have enabled the development ofBA calculators based onclinical and laboratory data, epigenetic modifications, immune signatures, microbiome, and multi-omics profiles. This article reviews various approaches to BA assessment, including epigenetic clocks (Horvath, GrimAge), phenotypic indices (PhenoAge, frailty index), immune aging models (iAge), and calculators derived from standard blood tests. The present review was prepared by conducting a comprehensive literature search utilising the PubMed and Scopus databases. A comprehensive search was conducted of original and review papers published primarily between 2010 and 2024, the focus of which was the description of BA estimation methods, their predictive utility, and clinical applicability. The review discusses the potential for integrating BA assessment into clinical practice and personalised medicine, as well as the need for further validation and standardisation of these tools across populations.

The global population is undergoing rapid ageing, with increasing life expectancy resulting in a proliferation of age-related health problems. An increasing number of people are becoming vulnerable to neurodegenerative diseases on an annual basis. These diseases are characterised by a progressive loss of nerve cells, motor or cognitive impairment, and the accumulation of abnormally aggregated proteins. A substantial body of research has demonstrated that oxidative stress can exert a multifaceted role in the development of diseases such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis (ALS), in addition to contributing to their progression and exacerbating the overall condition of patients. Mitochondrial dysfunction is a hallmark of the ageing process, particularly in organs that require high energy, such as the heart, muscles, brain, and liver. The brain is particularly vulnerable to free radical damage due to its high oxygen demand, limited antioxidant protection, and high content of polyunsaturated fatty acids, which are highly susceptible to oxidation. Nevertheless, the precise mechanism through which neurodegenerative diseases associated with disturbances in redox balance develop remains to be elucidated. A more profound comprehension of the molecular mechanisms associated with oxidative stress and neurodegeneration may facilitate the identification of novel avenues for the development of effective methods of prevention and treatment, which will have a favourable impact on the health of society.

More and more researchers in the field of neurodegenerative diseases are paying attention to non-cognitive manifestations that arise in old age. Their role is actively debated: whether they act as factors increasing the likelihood of developing severe cognitive impairment or represent early manifestations of the condition's first signs. This review presents information on the incidence of mild behavioral impairments (MBI) in patients with subjective cognitive decline (SCD) and mild cognitive impairment (MCI), which are associated with an increased risk of developing dementia. MBI syndrome, which is currently used in conjunction with MCI, is described in detail. Mild behavioral impairments are a new strategy aimed at predicting the development of dementia even before the onset of cognitive symptoms. Data from international studies over the past ten years devoted to the study of the influence of MBI on cognitive decline are summarized. Issues of differential diagnosis of these disorders and the methods used to diagnose MBI are considered.