A particular diet may be chosen to seek weight loss or weight gain. Changing a subject's dietary intake, or "going on a diet", can change the energy balance and increase or decrease the amount of fat stored by the body. Some foods are specifically recommended, or even altered, for conformity to the requirements of a particular diet. These diets are often recommended in conjunction with exercise. Specific weight loss programs can be harmful to health, while others may be beneficial and can thus be coined as healthy diets. The terms "healthy diet" and "diet for weight management" are often related, as the two promote healthy weight management. Having a healthy diet is a way to prevent health problems, and will provide the body with the right balance of vitamins, minerals, and other nutrients.
Many trainees like to cycle between the two methods in order to prevent the body from adapting (maintaining a progressive overload), possibly emphasizing whichever method more suits their goals; typically, a bodybuilder will aim at sarcoplasmic hypertrophy most of the time but may change to a myofibrillar hypertrophy kind of training temporarily in order to move past a plateau. However, no real evidence has been provided to show that trainees ever reach this plateau, and rather was more of a hype created from "muscular confusion".[clarification needed]
The number of asanas used in modern yoga has increased rapidly from a nominal 84 in 1830, as illustrated in Joga Pradipika, to some 200 in Light on Yoga and over 900 performed by Dharma Mittra by 1984. At the same time, the goals of Haṭha yoga, namely spiritual liberation (moksha) through the raising of kundalini energy, were largely replaced by the goals of fitness and relaxation, while many of Haṭha yoga's components like the shatkarmas (purifications), mudras (seals or gestures including the bandhas, locks to restrain the prana or vital principle), and pranayama were much reduced or removed entirely. The term "hatha yoga" is also in use with a different meaning, a gentle unbranded yoga practice, independent of the major schools, sometimes mainly for women.
Classical yoga incorporates epistemology, metaphysics, ethical practices, systematic exercises and self-development techniques for body, mind and spirit. Its epistemology (pramana) and metaphysics is similar to that of the Sāṅkhya school. The metaphysics of Classical Yoga, like Sāṅkhya, is mainly dualistic, positing that there are two distinct realities. These are prakriti (nature), which is the eternal and active unconscious source of the material world and is composed of three gunas, and the puruṣas (persons), the plural consciousnesses which are the intelligent principles of the world, and are multiple, inactive and eternal witnesses. Each person has a individual puruṣa, which is their true self, the witness and the enjoyer, and that which is liberated. This metaphysical system holds that puruṣas undergo cycles of reincarnation through its interaction and identification with prakirti. Liberation, the goal of this system, results from the isolation (kaivalya) of puruṣa from prakirti, and is achieved through a meditation which detaches oneself from the different forms (tattvas) of prakirti. This is done by stilling one's thought waves (citta vritti) and resting in pure awareness of puruṣa.
According to Georg Feuerstein, Laya yoga (yoga of dissolution or merging) "makes meditative absorption (laya) its focus. The laya-yogin seeks to transcend all memory traces and sensory experiences by dissolving the microcosm, the mind, in the transcendental Self-Consciousness." There are various forms and techniques of Laya yoga, including listening to the "inner sound" (nada), practicing various mudras like Khechari mudra and Shambhavi mudra as well as techniques meant to awaken a spiritual energy in the body (kundalini).
The practice of awakening the coiled energy in the body is sometimes specifically called Kundalini yoga. It is based on Indian theories of the subtle body and uses various pranayamas (breath techniques) and mudras (bodily techniques) to awaken the energy known as kundalini (the coiled one) or shakti. In various Shaiva and Shakta traditions of yoga and tantra, yogic techniques or yuktis are used to unite kundalini-shakti, the divine conscious force or energy, with Shiva, universal consciousness. A common way of teaching this method is to awaken the kundalini residing at the lowest chakra and to guide it through the central channel to unite with the absolute consciousness at the highest chakra (in the top of the head).
If you have high blood pressure, diabetes, or heart problems, ask your doctor what you can do. You may need to avoid certain postures, like those in which you're upside down or that demand more balance than you have right now. A very gentle program of yoga, coupled with a light aerobic activity like walking or swimming, may be the best way to start.