Metabolism is all the
chemical and physical processes within the body. We cannot perform these processes without
calories (energy). Resting metabolic
rate (RMR) employs the efforts of the brain, spinal cord, glandular systems,
organs, muscles, digestion, circulation, and reproduction – every function of
the body to maintain life at rest. RMR
accounts for 60-70% of all calorie-burning processes (Kinucan & Kravitz,
n.d.). We need to consume additional
calories to provide energy for all other activities.
The more you weigh the
more energy (calories) you need to maintain your weight; the less you weigh the
fewer calories needed to maintain your weight.
If you lose weight you will lower your metabolic rate. This means you will need fewer calories to
maintain your RMR and your new weight.
Our metabolism also decreases with age due to loss of muscle – strength
training will help slow down this process.
Be aware - some medications may increase RMR while others will decrease
RMR.
“Physical activity accounts
for 15-30% of daily calorie burn depending on an individual’s activity level,
which includes structured exercise as well as non-structured activity such as
shivering and fidgeting. The final
component, called thermic effect of food, is the energy required for the
digestion, absorption, transport, metabolism and storage of consumed food. It
accounts for approximately 10% of daily calorie burn” (Kinucan & Kravitz,
n.d.).
Below is a formula I like
to use to calculate resting metabolic rate (RMR):
Women: 661 + (4.38 x wt. in lbs.) = _____ + (4.38 x ht. in inches) = _____ - (4.7 x age) = RMR
67 + (6.24 x wt. in lbs.) = _____ + (12.7 x ht. in inches) = _____ - (6.9 x age) = RMR
Now that you have your RMR
you will need to determine how active you are to calculate how many additional
calories you should consume. Most people
tend to overestimate their daily activity.
Do you exercise one hour, two to three times per week only to find
yourself sitting during the other hours of the day? I suggest you use the “sedentary” multiplier
so you do not overestimate the number of calories you need per day. For example:
I perform one hour of cardiovascular exercise per day and I use the “moderately
active” multiplier. I have performed an
hour of cardiovascular exercise daily for the past 30 years and my body has
become accustomed to the activity (I would easily gain weight if I stopped my
daily exercise). I also perform strength
training and additional walking with clients 2-4 days per week, but I still
consider myself moderately active. There
have been times in my career I’ve had to teach 10-17 group fitness classes per
week in which case I would consider myself “very active.”
Activity Multiplier:
Multiply your BMR caloric
number with the appropriate activity multiplier to approximate the number of
calories you need to maintain your weight.
Sedentary …………………………………………………………………….. x 1.15
Light Activity (normal, everyday activity)
……………………………… x 1.3
Moderately Active (exercise 3-4 times per week)
…………………….. x 1.4
Very Active (exercise more than 4 times per week)
…………………. x 1.6
Extremely Active (exercise 6-7 times per week)
……………………… x 1.8
Good news – you can
increase your metabolism! As we age we
lose muscle which decreases metabolism. You can have the biggest impact on your
metabolism by scheduling time to exercise (cardiovascular and strength
training) and by moving more throughout the day.
A simple, inexpensive pedometer can help you be aware of your daily movement and encourage you to move more. Other more sophisticated gadgets include
FitBit and Body Media’s GoWearFit.
Whether you go low-tech or high-tech the objective is to move more and
balance calorie intake with calorie expenditures.
References:
Kinucan, P. & Kravitz, L. (n.d.). Controversies in metabolism. Retrieved from:
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