Katerina Georgieva

By Slavi Delchev and Katerina Georgieva

The mechanisms of the action of sex steroid hormones on the nervous system are related to both classical, intracellularly mediated effects and non-classical membrane effects due to binding to membrane receptors. Some steroids are capable of inducing rapid neurotransmitter-like effects, similar to those of dopamine or glutamate that alter the activity of neuronal systems via different types of receptors. The neuroactive steroids are endogenous neuromodulators synthesized in the brain and rapidly affecting neuronal excitability. Sex steroids exert many pleiotropic effects in the nervous system: they modulate main neurotransmitter systems, promote the viability of neurons, play an important role in myelination, and influence cognitive processes. Estradiol protects neurons from excitotoxic damage and increases neuronal survival. Progesterone stimulates neurological and functional recovery. Androgens also exhibit a wide array of neuroprotective effects in motoneurons, including supporting cell survival, axonal regeneration, and dendritic maintenance. Despite the considerable increase of sex hormones and neurosteroids research in recent years and the ongoing discovery of biochemical mechanisms of action, their role in neurodegenerative processes remains not well determined.

Part of the book: Sex Hormones in Neurodegenerative Processes and Diseases

By Nikolay Boyadjiev, Katerina Nikolova Georgieva and Penka Angelova Angelova Hristova

Physical activity improves the condition of the cardiovascular system, respiration, muscles, and metabolism and increases physical working capacity. This review of physiological effects and adaptation mechanisms of the outdoor recreation and its health benefits provides accessible information from a scientific point of view and research practice. Increased frequency of many socially important diseases such as diabetes mellitus type 2, metabolic syndrome and obesity, cardiovascular diseases, and others is associated with dramatically decreased physical activity in the last decades. Outdoor recreation for children, adolescents, adults, and older population is important for the prevention of these conditions. In this chapter, the authors describe in detail the physiological effects of different kinds of outdoor recreation physical activity with different intensities (such as walking, cycling, skiing, rowing, climbing, practicing some outdoor sports, etc.) and assess their benefits in the prevention of socially important diseases.

Part of the book: Outdoor Recreation