Aging is a process that affects all living things, including humans. Aging is not a disease but a vital phenomenon that involves everyone and is in fact a natural process during which the body changes physiologically and psychologically [1]. The aging process of humans involves a gradual decline in the function of body systems including cardiovascular, respiratory, urogenital, endocrine, and immune systems. Aging turns a healthy adult into a weak person with a decrease in various physiological capacities, increasing susceptibility to many diseases and death [2].
Today, thanks to advances in medical science, the world is experiencing a new phenomenon called population aging [5]. In the first half of this century, the world's elderly population is predicted to reach two billion by 2050 [6]. According to the 2016 census by the Statistics Center of Iran, our country has about seven million elderly people, which constitutes 8.8% of the population [7].
During old age, the risk of developing one or more chronic diseases increases, with cardiovascular disease, stroke, cancer, diabetes, musculoskeletal disease, and mental illness becoming more common [8]. One of the deficiencies that have currently attracted the attention of many experts is cognitive disorders among the elderly. Cognitive disorder is one of the most important and controversial disorders among the elderly and have different types [2].
Cognitive status depends on the full functioning of different brain systems. As age increases, declining and functional changes taking place in the brain cause dysfunction in these parts of the brain and result in cognitive problems. These problems can be very different and include a wide range of disorders in the elderly. Optimal cognitive function is a vital factor in promoting and maintaining mental health and quality of life in the elderly [1]. Numerous studies have shown disorders in the cognitive abilities of the elderly, including a decrease in linguistic performance, attention, orientation, and explicit and implicit learning ability [2].
The mild cognitive disorder is an intermediate condition between the normal cognitive status of old age and dementia, and it is a clinical syndrome that falls into the category of cognitive impairments. In this age-related memory disorder, there is no obvious functional impairment and the person's cognitive and memory impairment is not so severe that it interferes with the person's daily functioning, but the person's daily functioning is in any case weaker than normal, which occurs in the realm of memory or other cognitive domains. Benign aging is associated with slowing of neural responses in aging, yet the person's intellectual function and personality remain stable and they can remain independent in their daily lives. In many cases, the symptoms of this disorder are similar to the early symptoms of Alzheimer's, which can lead to dementia [10].
Mild cognitive disorder is a transitional stage of cognitive function between changes observed in normal aging and dementia, which provides an opportunity for early detection and prevention of Alzheimer's disease. Since mild cognitive disorder has adverse effects on quality of life and functional ability, it is vital to reduce its risk, and early diagnosis and intervention at the stage of the mild cognitive disorder can delay or prevent the onset of dementia [11]. As one of the clinical problems in the elderly, mild cognitive disorder is growing. Studies show that in the elderly with mild cognitive disorder, developing Alzheimer's disease increases by 10 to 30 percent per year, while in the elderly without it, the annual dementia rate is 1 to 2 percent. Despite effective treatments available to reduce the progression of the disease, many people with Alzheimer's remain undiagnosed for years [10].
There is currently no definitive treatment for cognitive disorders, so it is better to use preventive interventions for cognitive disorders [4]. One of the recently considered methods is yoga. Yoga is a physical-mental exercise that is related to physiological and psychological processes [12]. Its exercises are performed in both static and dynamic modes and it focuses on relaxation. Yoga includes meditation exercises, breathing regulation, and physical exercises [13]. There is some evidence that the activity of neurotransmitters as the main inhibitor of the brain can be affected through yoga exercises [14]. And such exercises generally reduce the symptoms of anxiety and increase relaxation and treatment of high stress and anxiety [15].
According to studies, yoga is a therapeutic technique that does not require special technology and equipment and can be done almost at any time and place. As a result, it is cost-effective and, more importantly, the individuals can do it independently [16]. Superbrain yoga is a type of yoga in which the main energy centers are the points of acupuncture. In this yoga, the person stands facing east, the legs open as wide as the shoulders and the tongue sticks to the palate. The acupuncture points of the ears (earlobes) are touched with the fingers of the opposite hand, that is, the right earlobe is touched with the left hand and the left earlobe with the right hand so that the hands are crossed in front of the chest. The index finger should point inward and the thumb should point outward. In the same state, the person performs 14 squats, inhaling while sitting down and exhaling while standing up (17, 18). Superbrain yoga balances the body's energy levels for optimal brain function (19). In mental and neurological disorders, energy is trapped in the lower chakras (the main points of acupuncture), thus preventing sufficient energy from being sent to the brain.
In 1997, reviewing the previous studies on the effect of yoga exercises on improving the balance of the elderly, Survey et al. showed that a moderate-intensity daily workout program of at least 30 minutes a day will help seniors maintain adequate levels of strength, balance, agility, and flexibility; and that exercises such as yoga which are done regularly can have positive effects on balance and some factors of physical fitness [20].
Since prevention precedes treatment, it is necessary to pay attention to mild cognitive impairment, which is the prelude to Alzheimer's disease. Considering the importance of quality of life in the elderly, whose population is growing, and the prevalence of cognitive disorders among them, and taking into account the growing trend of doing yoga exercises and its positive effects on strengthening intelligence and memory with very low side effects on the elderly, as well as the cost-effectiveness of this method, we decided to investigate the effect of yoga exercises on the cognitive function of the elderly.