Sun Salutation-A "Mini" Study

research Nov 29, 2010

Surya Namaskara ( Sun Salutation)

Prayer Pose

Two weeks ago Dr. Ken Sparks of the Cleveland State University (CSU) Health, Physical Education, Recreation, and Dance department (HPERD) and head of the CSU Human Performance Lab hooked me up to the COSMED Mobile CPET, which is a calorimetry device. Calorimetry is used to determine the heat released or absorbed in a chemical reaction. A ""calorimeter"" is a device that measures the heat of chemical reactions or physical changes and heat generated.The COSMED device measured my heart rate, maximal oxygen consumption, caloric expenditure, any many, many other physiological processes too numerous to mention, while I performed 10 minutes of the full version of Surya Namaskara (Sun Salutation). This was not an ""official"" study in anyway but just an opportunity for me to get an idea of the intensity and additional related effects of the Sun Salutation practice on the body. Every since I conducted a study on Surya Namaskara 2 years ago, I had more questions that I wished I could have answered in regard to overall intensity of the practice and calories expended while doing it.  Using this device was my opportunity to get an idea of the effects of the practice on heart rate and energy expenditure(calories burned) among other physiological responses. I am very fortunate to have access to resources in the Human Performance Lab at CSU as well as the expertise and guidance of an acclaimed exercise scientist. One of perks of working part time in the HPERD department!

Heart Rate and Workout Intensity The heart rate per minute results for the 10 minute period where I performed Sun Salutations showed that my heart rate averaged approximately 135 beat per minute (bpm).  The Karvonen formula, which can be used to determine Target Heart Rate,  illustrated that 135 bpm was at the low end of my Target Heart Rate Zone.

Karvonen Formula

THR = (( HRrest) × %Intensity) + HRrest


First I calculated my Maximum Heart Rate (MHR or HRmax )

220 bpm- 43 (my age)= 177 MHR

Then I calucated my Low Intensity Hear Rate Zone

177 MHR-54bpm (my Resting Heart Rate {RHR} or HRrest )=133bpm

133 X 65%( (Low Intensity Target Heart Rate {THR})= 86 bpm

Add Resting Heart Rate Back into the Equation

86 +54 (Resting Heart Rate)=140bpm Low End Heart Rate

Next I calculated my High Intensity Heart Rate Zone

177 MHR-54bpm (my Resting Heart Rate {RHR} or HRrest )=133bpm

133bpm X 85% (High Intensity THR)= 113 bpm

Added Resting Heart Rate Back into the Equation: 133bpm X 85% (High Intensity THR)= 113 bpm

113bpm+54bpm =167 bpm

My Target Heart Rate Zone is 140bpm-167bpm

Target Heart Rate Zone The Target Heart Rate zone is the desired range to reach during aerobic exercise and sets the stage for the heart and lungs to receive maximum benefit from exercise efforts. It is used during exercise to measure effort and to gauge the intensity of the workout.  According to my ""Target Heart Rate Zone"" calculated above, an average heart rate of 135 bpm would be near the low end of the range and therefore be considered ""low intensity,"" My  average heart rate during that period of time, 135 bpm  was approximately equivalent to a brisk walk. While I didn't feel as though I ran a 6 minute mile, I was slightly winded at the end of the 10 minutes. The 135 bpm that I averaged is close to the low end of my target range and is  substantially more than my resting heart rate of 54 bpm.  For the last 3 minutes of the practice, however,my heart rate continued to climb and averaged 143bpm. It may not be in my ""high intensity"" range but the the practice was moving me in that direction and will probably do the same for you!

How Many Calories Are Burned While Doing Yoga? Students are always asking ""How many calories will I burn doing yoga?"" I was really most interested to have some hard numbers when it came to caloric expenditure. Since I have been singing the praises of Sun Salutation for over 2 years now, I figured ""calories burned"" always seems to get people's attention so this could information could add more to my ""Benefits of Sun Salutation"" arsenal. In the past I have told my students that it is difficult to say how many calories someone burns while practicing yoga because it depends on the persons body composition, their cardiovascular and muscular endurance level, the intensity of postures, and the length of the yoga practice. All of which are difficult to measure (except for duration or practice) without doing a lot of calculations and tests before hand as well as having fancy measuring devices such as heart rate monitors, calorimetry devices , etc. Although many of the physiological benefits of the yoga practice are often difficult to measure, my thought is that Sun Salutation (modified version for less experienced or full version for more experienced) is a rather rigorous.  If each pose is performed correctly with approximately one breath per posture, I believe the intensity can be somewhat similar person to person, routine regardless of one's physical shape or yoga experience.

This is a theory with many holes, but I believe the series can be a good starting point for trying to measure calories burned per minute while practicing yoga. Perhaps another ""official"" study is in order!

Calories Burned Per Minute The results showed that I burned approximately 7 calories per minute which puts the workout in the ""low intensity"" range. Of those 7 calories per minute, approximately 6.3 fat calories were burned. The percentage of fat calories expended was 90% of all calories burned.  Sounds pretty good to me.  However, if the workout would be ""high intensity"" (Heart rate at 80-85% of maximum) the approximate calories burned would be 14 calories per minute with 8.4 calories per minute being fat calories. The American College of Sports Medicine suggests that for a workout to be considered a fat burning workout then the workout should burn a minimum of 300 calories. While Sun Salutation, at least for the 10 minutes that I was being tested, doesn't show to be high intensity,or did I burn 300 cal ( I burned about 70) it does have added benefits that say running or other cardiovasularly intense workouts don't.

Added Benefits of Sun Salutation As shown in the study I conducted for my graduate thesis, a beginner yoga practitioner practicing Sun Salutation for 10 minutes per day 4 times per week for 6 weeks showed a significant improvement in hamstring flexibility and upper body strength. This is really something to consider. How many forms of exercise put you in the fat burning range AND increase flexibility AND Upper body strength?

Summary Again, looking to get more ""bang for your buck"" when it comes to exercise? Surya Namaskara or Sun Saluation can be the answer. It is a full body workout that has physiological benefits far beyond what I have discussed in this and previous posts. Even if you don't have access to a Human Performance Lab you can do some basic calculations on your own.Taking your resting pulse at the carotid or radial artery. It is best to take it for one full minute upon waking.  Using your resting heart rate (RHR) you can then  calculate your own Target Heart Rate Zone, which can be done by using the formula above or a Karvonen calculator intensity of the workout and the approximate calories expended. Wishing you much flexibility, strength, and many calories burned as you give this yoga practice a go.

(Videos): Surya Namskara-Modified Version, Full Version of Surya Namaskara