Does yoga increase fitness as well as other types of exercise do?  The answer is yes, if done within certain parameters.  For example, in a study conducted looking at physiological changes in adult women, researchers looked at the short-term effects of four weeks of intensive yoga practice in six healthy adult female volunteers measured using the maximal exercise treadmill test.  Yoga practice involved daily morning and evening sessions of 90 minutes each.  In this group, the maximal workout increased by 21%, oxygen consumption per unit of work decreased, demonstrating an increase in cardiorespiratory efficiency.3  In another study, a comparison was made between the effects of yoga and the effects of physical exercise in athletes.  This inquest focused on the effect of pranayama (controlled breathing).  This study was a well-done investigation which lasted for two years, examining a control group and an experimental group.  The results showed that the subjects who practiced pranayama could achieve higher work rates with reduced oxygen consumption per unit work than the control group,  and without an increase in blood lactate levels.4 In a study conducted which looked at aerobic capacity and perceived exertion after practice of Hatha yogic exercises, investigators found that the practice of Hatha yogic exercises helps to improve aerobic capacity like the practice of conventional exercises (PT). The yoga group practiced yoga for one hour every morning (six days a week) for six months. Interestingly, the yoga group performed better than the PT group in terms of lower ratings of perceived exertion after exhaustive exercise5, bringing in the mind-body connection which is so unique to yoga. 
 
 What about the other parameters of fitness?  In a study performed at the University of California at Davis, students performed eight weeks of yoga training after which muscular strength and endurance, flexibility, cardiorespiratory fitness, body composition and lung function was tested.  Each week, the students attended four sessions in which they performed 10 minutes of pranayama (breathing), 15 minutes of warm-up exercises, 50 minutes of asanas (yoga poses), and 10 minutes of relaxation.  Significant improvements were noted in muscular strength (31%), muscular endurance (57%), flexibility (up to 188%), and VO2max (7%).   Other studies reviewed by our resources indicated increases in respiratory efficiency and competence, cardiovascular efficiency and competence, and decreases in oxygen consumption.
 
 So, can participants become “fit” if they just do yoga?  Well, that depends.  As one can note by looking at the few studies described above, these positive results came only after practicing yoga according to certain guidelines.  Studies have included more than an hour of practice at least two to fours days a week.  The yoga sessions included breath work in addition to the typical yoga poses.  The asanas included Sun Salutations and challenging standing and balancing poses.  Flow yoga was designed is just this way.  At FLOW yoga, the instructors follow a vinyasa style yoga that trains the body to increase physical endurance by flowing through the poses.  The mind also is being trained to stay focused for the duration of the class.  Vinyasa links poses together flowing with the breath, in order to increase strength and endurance. Of course, the practitioner needs to practice several times a week, for at least 60 minute sessions, to incur the benefits proven so far by scientific studies.  If one is able to do this, not surprisingly, the fitness benefits fall in line with the benefits achieved by other forms of exercise.
 
 The content of the class must also be quite vigorous.  Dee Ann Birkel, an emeritus professor at Ball State’s School of Physical Education, and others point out that the Sun Salutations and other continuous linked poses increase the heart rate, making yoga aerobically challenging.  Also, the sustained isometric contractions required of the large and small muscle groups in standing poses increase strength.   The concentric and eccentric work required to move in and out of poses in a controlled manner lifting our own body weight and the weight of our limbs serves also to increase our strength.2  Balance poses require co-activation of our core stabilizing muscles, increasing stability and strength throughout our trunk.    Practicing a flowing style of yoga will increase their fitness levels, as long as they practice yoga according to established study guidelines.

Part II