Rev Up Your Metabolism
Simply put, metabolism is the rate at which your body makes and burns energy, or calories. According to WebMD, metabolism involves a complex network of hormones and enzymes that convert food into the fuel your body needs for doing everything from pumping blood to exercising.
One measure of metabolism is the Resting Metabolic Rate (RMR), which is the number of calories used in vital body functions that keep you alive (e.g., breathing). RMR for each individual is different and is influenced by a number of factors, including your genetics, hormones, gender, age, exercise levels, and body weight.
Measuring RMR
RMR typically accounts for about 65 to 75 percent of your total daily calorie expenditure, according to doctors at the American College of Sports Medicine. So RMR is a good starting point to determine how your body burns fuel. For an average-sized man who is not an elite athlete, RMR is typically around 1,800 calories per day. For an average-sized woman, RMR is generally around 1,400 calories per day.
A mathematical way to measure RMR is to use a standard formula that factors in your sex, weight, height, and age. Commonly called the Harris-Benedict equation, here’s the calculation:
-Women: 655 + (9.6 x weight in kilograms) + (1.8 x height in centimeters) – (4.7 x age in years)
-Men: 66 + (13.7 x weight in kilograms) + (5 x height in centimeters) – (6.8 x age in years)
An online calculator (that also converts to inches and lbs.) at Calories Per Hour makes this easy.
To make RMR slightly more personal to your lifestyle, include an activity factor. An active swimmer with vigorous daily exercise should multiply the result by a factor of 1.5. Elite swimmers might even multiply by 1.75 to 2 or higher. Finding this number gives you the approximate number of calories your body needs each day to maintain its current weight.
Here’s how the elites stack up with this formula, applying the 1.9 extremely active factor:
-Michael Phelps: 3,806 calories
-Ryan Lochte: 3,659 calories
-Dara Torres: 2,759 calories
-Natalie Coughlin: 2,678 calories
For a more accurate calorie burn assessment, try one of the high-tech gadgets available. One is called BodyGem, a handheld device that measures oxygen consumption to determine RMR. Another more complex method is New Leaf, which an athlete can wear while on a bike or treadmill to determine calories burned during exercise. These calculations could be helpful to an endurance athlete who wants to track the point at which they reach an anaerobic threshold, or “hit the wall” and stop burning oxygen efficiently.
Burn, Calories, Burn
If your metabolism is not where you want it to be, good news—you can boost it. One proven way is through consistent strength training. The more muscle you have, the higher your metabolism. Scientifically speaking, one pound of muscle burns 30 to 50 calories per day, while one pound of fat burns a measly two to 10 calories per day.
Also, try eating smaller meals and snacks every three to four hours. Researchers from Georgia State University reported that when athletes ate 250-calorie snacks three times a day, they had greater energy output then when they didn't snack. Snacking helped the athletes eat less at each of their three regular meals. The final result was a higher metabolic rate, a lower caloric intake, and reduction in body fat.