A grandma and her grandchild watching the Nowruz ceremony, showing stark contrast in physical appearance<unk>  (BE) or<unk>  (AE) is the process of becoming older. The term refers mainly to humans, many other animals, and fungi, whereas for example, bacteria, perennial plants and some simple animals are potentially biologically immortal. Furthermore,<unk>  connotes a biological and social construct. It is usually associated with dynamic changes in the biological, psychological, physiological, environmental, behavioral and social processes. In the broader sense,<unk>  can refer to single cells within an organism which have ceased dividing or to the population of a species. In humans,<unk>  represents the accumulation of changes in a human being over time and can encompass physical, psychological, and social changes. Reaction time, for example, may slow with age, while memories and general knowledge typically increase.<unk>  increases the risk of human diseases such as cancer, Alzheimer's disease, diabetes, Cardiovascular disease, stroke and many more. Of the roughly 150,000 people who die each day across the globe, about two-thirds die from age-related causes. Current<unk>  theories are assigned to the damage concept, whereby the accumulation of damage (such as DNA oxidation) may cause biological systems to fail, or to the programmed<unk>  concept, whereby problems with the internal processes (epigenetic maintenance such as DNA methylation) may cause<unk> . Programmed<unk>  should not be confused with programmed cell death (apoptosis). Additionally, there can be other reasons, which can speed up the rate of<unk>  in organisms (including human beings), like obesity and compromised immune system. Scientists have long known that dietary calorie restriction in non-primate animals slows<unk>  while maintaining good health and body functions. Rats and mice fed 30 to 50% fewer calories than they would freely eat beginning in early life shows various physiological health benefits, lower incidence of chronic diseases, and up to 50% increase in length of life. Though life-extending effects remain uncertain in primates (including humans), the diverse health benefits of limiting calorie intake are now well-established. They seem to result from a physiological response to food scarcity that evolved to enhance the body's capacity to survive adversity. Nevertheless, few people would be willing to maintain a substantially reduced diet for most of their lifespan. As a result, scientists have begun to explore calorie-restriction mimetics-natural and synthetic drug compounds that might yield the same health effects as calorie restriction, without dieting. These investigations are still in their early stages. Biologically,<unk>  results from the impact of the accumulation of a wide range of molecular and cellular damage over time. Thus, this leads to a gradual decline in physical and mental capacity, a growing risk of diseases, and ultimately, death. These changes are usually consistent, and they are associated with a person's age in years. While some people aged 70 years may be strong and enjoy good health, others who are 70 years may be weak and require others to help them. The medical discipline of rejuvenation deals with the artificial reversal of biological<unk>  processes. In this field of research,<unk>  is understood as the accumulation of damage in macromolecules, cells, tissues and organs in the course of life, which must be repaired.
Ageing
Proteinopathy
Tauopathy
Neurocristopathy
Premorbidity
Synucleinopathy
Multimorbidity
Diabetes