"…for person's wanting to lose weight there will have to be a meaningful change in caloric intake as well as the adoption of aerobic exercise to increase the caloric deficity needed for weight loss…"
FitCommerce:
Good morning Dr. Kravitz. Please tell us about your labs at the University of New Mexico, are you able to do a lot of primary research there?
Len Kravitz: Yes, we have extensive facilities for exercise physiology testing and research. In particular we can do all aspects of gas analysis testing for oxygen consumption studies such as energy expenditure and aerobic capacity testing.
We are fully equipped for all types of body composition assessment with a Bod Pod, hydrostatic weighing tank, residual lung volume assessment, and bioelectrical impedance testing. In addition, we have an altitude chamber where we can do altitude studies. As well, we have a heat chamber for thermoregulation studies. Finally, we are equipped to do all kinds of clinical tests such as EKG stress tests.
Q:
What types of physiological data do you capture and analyze?
A:
I am very involved in studies of energy expenditure. I test a lot of new products and programs, assessing the energy demands of the activity or product. In addition, I am very involved in developing new submaximal testing protocols for the prediction of maximal aerobic capacity on various modes of exercise.
Q:
With the Fall semester about ready to start, anything in particular your students will be looking at?
A:
This semester I have several students working on energy expenditure studies with me. We are investigating the energy expenditure differences in high volume versus high intensity multiple joint exercises. As well, I am looking at the perceived exertion differences between different modes of exercise.
Q:
That's really exciting…Shifting gears for a moment, many trainers have to deal with various populations about their weight management. We hear a lot about the Resting Metabolic Rate and it's potential effect on weight gain or weight loss, are people barking up the wrong tree to think that metabolism can be affected to alter body weight?
A:
Excellent question. I think for decades we have believed that we can dramatically change metabolism to positively affect weight loss. There have been countless pills on the market that have totally marketed this type of effect and of course Ephedrine is the most well-known. In some cases Ephedrine, which is a central nervous stimulant, may lead to very dire consequences in those who are risk to cardiovascular health.
In addition, we have see countless claims about the metabolism boosting effects of resistance exercise. I think this is the biggest myth out there with personal trainers and fitness professionals.
Let's set the record straight. Resistance exercise is incredibly important in weight loss programs as it very successfully inhibits the muscle loss, one of the most metabolically active tissues in the human body. However, the metabolic boosting claims about resistance exercise are exaggerated.
Research clearly shows the metabolic
expenditure of muscle is 15-25 kilocalories/kg of muscle
per day.
Most short term and long-term research shows that most people increase their muscle mass about 2 kg from resistance training. Thus, the actual change in metabolism from resistance exercise is really closer to 50 kcals per day.
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Most people can increase their muscle mass by about 2 kg from resistance training. This can increase their metabolism to burn roughly 50 kcals per day.
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Q:
Just what is the Resting Metabolic Rate?
A:
Resting Metabolic Rate
is the energy needed for the human body to stay alive. All cell life requires energy and resting metabolic rate is the energy to maintain all of the body's cells and life-sustaining reactions. This represents 50-75% of your total energy expenditure needs.
Q:
Just so we're clear, if it were possible to increase one's RMR, then it would be burning extra calories, 24/7?
A:
That is correct. And from the resistance exercise research, most people see an increase on a daily basis of 50 extra kilocalories per day from the 2 kg of muscle mass that is typically added from resistance exercise. For prevention of weight gain, this extra 50 kilocalories is helpful.
However, for person's wanting to lose weight there will have to be a meaningful change in caloric intake as well as the adoption of aerobic exercise to increase the caloric deficity needed for weight loss.
Q:
Wow, that's an eye opener, O.K. the $64,000 question, how does one go about increasing their RMR?
A:
Wouldn't it be so nice if we could modify this easily. Aerobic exercise will not increase metabolic rate.
People who diet, without exercise, often show a decrease of RMR by 20%, which makes losing weight even more difficult. Resistance exercise as noted above will increase RMR, but not nearly enough as once suggested by the media. No pills can safely work either.
Therefore, for weight loss interventions, actually changing a person's metabolism is not a viable option. There has to be a combined approach of caloric intake restriction with caloric output increase (via aerobic exercise) and resistance exercise becomes very important in maintaining the body's muscle mass.
Q:
Is it logical to presume that all populations can add lean muscle mass and keep it on, especially as they age? What kind of effort would that take?
A:
Those individuals who train 2-3 days a week with total body progressive resistance exercise programs should realize these muscle mass gains as long as they are consistent with the resistance exercise programs.
At the recent DCAC conference you spoke about a non-exercise means of burning calories throughout the day called "NEAT", can you briefly describe what NEAT is?
NEAT is the newest component of energy expenditure and a fast growing area of research in metabolism. It is Non-Exercise Activity Thermogenesis and refers to all NON-structured physical activity we do in our daily lives such as walking, moving, fidgeting, standing, and moving while sitting.
This type of research uses highly sensitive inclinometers and triaxial accelerometers worn on the hips and legs of the body (under the clothes) to monitor all bodily activity. These devices are like highly sophisticated pedometers.
Q:
Do all those extra NEAT minutes of activity in a day really amount to anything, in terms of an exercise session what does it equate to?
Walking your kids and your dog after meals is a great way to get NEAT caloric expenditure in your day.
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A:
New research shows that people who move a lot actually burn an extensive amount of calories as compared to their less mobile counterparts. In a recent study with lean subjects (who did not exercise) versus obese subjects (who did not exercise) it was found that lean individuals moved about 2.5 hours more per day. The extra movement by the lean subjects averaged 352 ± 65 calories per day, which is equivalent to 36.5 lbs in one year.
These 352 calories from just being more active during the day is equivalent to a 40-minute moderate intensity aerobic workout on most modes of exercise. So, this extra movement during the day, often referred to as spontaneous physical activity, is very meaningful.
Q:
In conclusion, what handful of activities can people adopt in the normal course of their day to burn off some NEAT calories, without a major strain on their busy schedule?
A:
I encourage everyone to visit the website,
smallstep.gov
which is a website developed to getting people more active during the day. Here are some examples:
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- Walk around the mall a couple of times before starting to shop;
- pace while you talk on your cell phone;
- walk your kids and your dog after meals; get off a couple of stops early off a bus and do some walking;
- walk to a colleagues desk instead of emailing or calling him/her; take a walk and stretch break regularly at work;
- and park in the back of a parking lot (during daylight when it is safe) and walk to the store.
Many more ideas at 'smallstep.gov'
FitCommerce:
Fantastic advise, as usual, Dr. Kravitz. Thank you for your time.
About Dr. Len Kravitz
Dr. Kravitz is the Program Coordinator of Exercise Science, and a researcher at the University of New Mexico. He has his PhD. In Health Promotion and Exercise Science, and his M.A. in Physical Education. He is the first person to win the IDEA Fitness Instructor of the Year (1987) and a recent recipient of the Canadian Fitness Professionals International Presenter of the Year. He has authored 4 books and produced 6 exercise videos.
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