Nearly 20 million people are practicing yoga today in the United States, and it has entered the mainstream as a hip and trendy way to get in shape, sculpt lean muscles and improve overall athletic performance and mental focus. Once you begin to incorporate yoga postures into your training regimen or even devote an entire workout to yoga, you’ll find that it’s the integration of your physical, mental, emotional and spiritual body.

What does that really mean?

Students of yoga will get healthier, and eventually learn to center themselves, be present and aware, and to identify with their highest athletic self.

Physical exercise has a protective effect on the brain and its mental processes, and may even help prevent Alzheimer’s disease. Based on exercise and health data from nearly 5,000 men and women over 65 years of age, those who exercised were less likely to lose their mental abilities or develop dementia, including Alzheimer’s.

Furthermore, the five-year study at the Laval University in Sainte-Foy, Quebec, suggests that the more a person exercises, the greater the protective benefits for the brain, particularly in women. In the revolutionary study, inactive individuals were twice as likely to develop Alzheimer’s, compared to those with the highest levels of activity (exercised vigorously at least three times a week). But even light or moderate exercisers cut their risk significantly for Alzheimer’s.

When you come to your mat and close your eyes (to meditate or to simply slow your thoughts and deepen your breathing, several hormonal and physiological things happen almost instantly:

• As you breathe deeper, more oxygenated blood courses throughout your circulatory system, which helps lower stress hormones which can compromise the immune system. This oxygen-rich blood also conditions and strengthens the lungs and respiratory tract.

• The lymphatic system is strengthened and toxins are swept away during physical practice. You may notice that you get far fewer illnesses when you have a regular yoga practice. Sometimes, students come to class with a sniffly nose, and several postures (and breathing drills) can clean out their cardiorespiratory system enough so that they walk out of class feeling much healthier once the toxins are eliminated.

• Moving into deeper poses slowly and progressively provides freedom from a variety of diseases like migraine, headache, insomnia and even arthritis. It increases the metabolism of the body in a controlled manner and helps you to feel better.

• Yoga boosts mental and emotional strength even as it simultaneously provides proper toning to the body. Joints become stiff with age and also due to a stagnant lifestyle –- but so does the mind! Yoga provides flexibility to all body parts and the mobilization exercises help make the body active so as to undertake a variety of daily chores with greater functionality.

• Yoga cultivates focus and concentration and reduces stress by making you less reactive. It especially opens the spine, the hips and the shoulders, where all stress hides and strengthens the many systems of the body, like the circulatory system, the immune system, and the endocrine system. Yoga calms the mind, steadies emotions and opens the heart to feeling more vibrantly alive, giving you a sense of empowerment. As a result, you become more comfortable in your body.

• When you feel better in your body, you feel better about yourself and act better towards others. That’s the goal… in the midst of a stressful day, yoga provides a reprieve from ringing phones, screaming managers, testy kids, and all the intrusions upon your day or your workout. Yoga restores calmness, balances the emotions, and nourishes your internal body.

• An open and flexible mind energizes and prepares one for change. Some believe that visualization helps in the transformation of thoughts to a new life of hope and success. By visualizing mental pictures of success, one can take measures toward converting dreams into reality. Some believe the best time for visualization is in the morning. Closing the eyes and doing 5 to 10 minutes of your favorite yoga postures provides an opportunity to find inspiration and self-motivation as one imagines how to go about changing life.

The science of how yoga empowers the mind and emotions is so tangible that there’s a new and burgeoning field called “yoga therapy,” where certain practitioners (including psychiatrists, psychologists and social workers) incorporate yoga poses and meditative breathing into their sessions, as well as yoga teachers who want to learn how to address the emotions that bubble up in students during class or in private sessions. The idea is to allow yoga to empower people while priming them to access their deepest emotions.

Time Magazine reported that since the days of Freud, research into the mind-body relationship has come a long way. Studies show that not only are your mental health and mood dependent in large part on physical factors like exercise, but also unchecked stress, anxiety and depression can affect physical health, increasing blood pressure, heart disease, and even risk of death. So it was perhaps inevitable that patients would start bringing their yoga mats into therapy.