Tuesday, November 10, 2015

How Many Calories are You Burning?

Resting Metabolic Rate (RMR) is the energy required to maintain the systems of the body and to regulate body temperature at rest.  RMR accounts for approximately 60-80% of total daily energy expenditure and therefore play a major role in energy balance and overall weight management.  The remaining 20-40% of calories burned throughout the day depends on your activity level (which includes basic occupational activities as well as exercise and sport activities).  It's important to know and understand what your RMR is so that you can set goals for yourself in regards to calories in vs. calories out.  Below is a list of factors that influence RMR in addition to a way to identify this value for yourself:

Factors that influence RMR:

Effect on RMR
↓ 1-2% per decade
↑ RMR with ↑ weight
Fat Free Mass
↑ RMR with ↑ FFM (the more muscle the higher your RMR is)
Fat Mass
↑ RMR with ↑ Fat Mass (slight)
Typically higher in Males when compared to females
Body Temp
12% ↑RMR with each 1 degree C increase
Severe Dieting
Menstrual Cycle
↑ RMR slightly (especially during luteal phase)
Acute Exercise
↑ RMR (depends on intensity and duration of exercise)
Thyroid Levels
↑RMR w/ higher levels and ↓ RMR when levels are low
↑ RMR (acutely)
Smoking (Acute)
200-400 mg can ↑ RMR 5-15%

A quick and easy estimation of your resting metabolic rate can be found below:
10.2 x (weight in lbs) + 879
7.18 x (weight in lbs) + 795
The number above will tell you roughly how many calories you would burn if you were to lay in bed all day long.  This number will obviously increase if you are active whether it be occupational, training, or exercise and therefore you can use activity factors to try and estimate your total calorie expenditure for the day (See below):
  • If you are sedentary (little or no exercise) : Calorie-Calculation = BMR x 1.2

  • If you are lightly active (light exercise/sports 1-3 days/week) : Calorie-Calculation = BMR x 1.375

  • If you are moderatetely active (moderate exercise/sports 3-5 days/week) : Calorie-Calculation = BMR x 1.55

  • If you are very active (hard exercise/sports 6-7 days a week) : Calorie-Calculation = BMR x 1.725

  • If you are extra active (very hard exercise/sports & physical job or 2x training) : Calorie-Calculation = BMR x 1.9

This number will be the number of calories you should consume if you are trying to maintain your current weight. If you are trying to lose or gain weight you simply reduce/increase daily calories by ~300-600 calories, respectively.  Keep in mind these numbers/values are just educated guestimations and not everyone responds in the same way. These are ballpark figures to start with and help guide you along the way but it will need to be tailored to your individual needs and differences.

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