Most people equate yoga with doing exercise. But there are some fundamental differences. First of all, yoga is about conserving energy and not wasting it. Some forms of yoga can be strenuous, but they are aimed at younger people with an abundance of energy that needs to be used up. Like letting off steam. If you are an older person or one that has children or other people to care for, your extra energy probably gets used up in your day-to-day responsibilities. So you want your yoga to restore lost energy.
Yoga restores energy by slowing down your breathing, reducing your oxygen intake and lowering blood pressure. The different types of poses you practice in a yoga class take blood to the organs. In physical exercise blood is directed to the muscles that are working so hard. Physical exercise can give joints a pounding, yoga keeps joints flexible and strong.
Yoga postures are designed to keep the system that controls hormones healthy. Hormones that are out of control or simply lacking, can cause both physical and mental problems. In essence, yoga looks out for the whole of the body. The physical, mental and emotional aspects. The relaxation session at the end of a yoga class is important. Not only does it give you space to switch off and relax, it also ensures that the benefits of what you have been taught in the class reach the parts of the body they are aimed at.
I always say to my students that they should leave a yoga class with more energy than they come in.