According to Dave Costill, PhD, Professor Emeritus at Ball State University and one of the first US researchers to rigorously test the health and fitness benefits of exercise, fitness can be defined as the "ability to live your life without feeling fatigued." An all-embracing definition from the American Council of Sports Medicine (ACSM) states that fitness is related not only to maintaining physical activity but also relating to your health (for example, someone reducing his risk of heart disease by becoming more fit.) The ACSM describes fitness as consisting of the following: cardiorespiratory fitness, muscular fitness, flexibility and body composition. Experts have long recommended that we do at least three different types of activity to improve our fitness level. So, according to the latest studies, how does Hatha yoga fit into today's prescription for fitness?
Hatha yoga means "yoga for health" and is the physical aspect of the practice of yoga. It renews, invigorates and heals the body, stretching and strengthening the muscles, joints and spine and directing blood and oxygen to the internal organs (including the glands and organs and nerves.) Practitioners credit yoga for everything from improving their strength, respiration and fitness levels to "opening energy channels." While these anecdotal reports passed on through the years are real and meaningful, we must take care to assure that any benefits we express to our clients are more than "yogi lore" and are based on expert opinion and scientific research. Many times, a red flag goes up in a client's mind when the instructor mentions that a certain pose or practice will, for example, "stimulate digestion or improve energy levels." One may wonder if this is just fable passed on through the years, backed up only by personal experience.
We can pull from current research and make some basic inferences regarding the benefits of the practice of yoga to our health. The preliminary results are promising, but they should be shared with the understanding that conclusive benefits have not yet been proven. The studies that have been done have looked at various areas of benefit that one might receive from the practice of yoga. These areas include behavioral, physical, mental, physiological, personality and disease processes.
The focus of this article is on what is usually foremost on the minds of participants who take yoga at their local fitness facility or gym: fitness. The population most widely served by power or vinyasa styles of yoga may want to know if doing yoga will promote 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 percent, oxygen consumption per unit of work decreased, demonstrating an increase in cardiorespiratory efficiency.
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 that 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.
In a study that looked at aerobic capacity and perceived exertion after practice of Hatha yogic exercises, researchers found that the practice of Hatha yogic exercises along with games helps to improve aerobic capacity like the practice of conventional exercises. 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 exercise, bringing in the mind-body connection that is unique to yoga.
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, 15 minutes of warm up exercises, 50 minutes of asanas and 10 minutes of meditation. Significant improvements were noted in muscular strength (31%), muscular endurance (57%), flexibility (up to 188%), and VO2max (7%). The VO2 increase was particularly interesting as this study lasted eight weeks, while the ACSM recommends that exercise research last at least 15 to 20 weeks in order to see VO2 max improvements. Other studies indicated increases in respiratory efficiency and competence, cardiovascular efficiency and competence and decreases in oxygen consumption.
So, can we tell our clients if they just do yoga, they will be "fit?" 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 pranayama work in addition to the typical yoga poses. The asanas included Sun Salutations and challenging standing and balancing poses. The good news is that the content of the yoga described in the studies is inherent in the power or vinyasa styles of yoga. In these styles, we are training 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. We also use "vinyasas," several poses linking together and 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 be quite vigorous. Sun Salutations and other continuous linked poses increase the heart rate, making the 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. Balance poses require co-activation of our core stabilizing muscles, increasing stability and strength throughout the trunk.
So in summary, practicing forms of vinyasa yoga will increase fitness levels, not unlike other forms of exercise, as long as established fitness guidelines are followed.
Summary of Health Benefits of Yoga Vs. Conventional Exercise
|Parasympathetic nervous system dominates
||Sympathetic nervous system dominates
|Subcorticol regions of brain dominate
||Corticol regions of the brain dominate
|Slow, dynamic and static movements
||Rapid forceful movements
|Normalization of muscle tone
||Increased muscle tension
|Low risk of injuring muscles and ligaments
||Higher risk of injury
|Low caloric consumption
||Moderate to high caloric consumption
|Effort is minimized, relaxed
||Effort is maximized
|Energizing (breathing is natural and controlled)
||Fatiguing (breathing is taxed)
|Balanced activity of opposing muscle groups
||Imbalanced activity of opposing muscle groups
|Noncompetitive, process oriented
||Competitive, goal oriented
|Awareness is internal
||Awareness is external
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