Your Metabolism

Publication Date: 
Fri, 08/01/2014
By: Alere Staff

Your body’s metabolism is a complex physical and chemical process by which your body converts what you eat and drink into energy.1 The energy is released into your body when the calories from the food you eat are mixed with oxygen. Your body uses the energy to help fuel functions such as breathing, regulating hormones, and for cell repair and growth. Your body uses energy whether you are active or resting.

The number of calories your body burns carrying out its most basic functions, such as breathing, circulation, etc., is called the basal metabolic rate. This metabolic rate does not easily change since the amount of energy your body needs for basic functions is fairly consistent.1 You can determine your basal metabolic rate (BMR) using a standard formula, or by using online calculators that ask you to input your age, sex, weight, height, and sometimes your body fat percentage. Many individuals use this number to help understand how many daily calories you need to consume to either maintain your current weight or lose weight.

There are several factors that determine the number of calories your body uses to carry out those basic functions1, 2, 3:

  • Body composition and size – larger individuals with more muscle burn more calories
  • Male or female – men tend to burn more calories
  • Your age – BMR decreases by 5% per decade after age 40

As you can see from the factors above, not everyone burns calories at the same rate. While you don’t have much control over the speed of your metabolism, you can control how many calories you burn with physical activity and exercise.

How does my metabolism affect medicine, like warfarin?

How a drug is absorbed in your body depends on several factors, including blood flow and metabolic activity.4 For warfarin specifically, the drug is more dependent on your metabolism and physical activity.5 Although much is still unknown about the interactions between exercise and medications, one study did find that increasing physical activity in patients taking warfarin has been shown to decrease the International Normalized Ratio (INR).5

Talk to your doctor about your weight, questions about metabolism, and your exercise routine. Work with your doctor to come up with a physical activity or exercise plan that you enjoy and that matches your abilities. For additional ideas on how to make physical activity part of your life, read the article on Exercise & Physical Activity. Keep in mind that any change in physical activity should also be reported to your doctor so they can monitor the effect, if any, that your new exercise regime has on your INR results and warfarin dosing.

  1. Speakman, J. R., Westerterp, K. R. Associations between energy demands, physical activity, and body composition in adult humans between 18 and 96 y of age.Am J Clin Nutr. October 2010 vol. 92 no. 4 826-834.
  2. Elsas LJ II. Approach to inborn errors of metabolism. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 212.
  3. Roberts, S. B. ,Rosenberg, I. Nutrition and Aging: Changes in the Regulation of Energy Metabolism With Aging. Physiol Rev April 2006 vol. 86 no. 2 651-667.
  4. DiPiro JT, Spruill WJ, Blouin RA, Pruemer JM. Concepts in Clinical Pharmacokinetics. 3rd ed. Bethesda, MD: American Society of Health-Systems Pharmacists; 2002.
  5. Lenz TL, Lenz NJ, Faulkner MA. Potential interactions between exercise and drug therapy. Sports Med. 2004;34(5):293–306.