How Many Calories Do You Burn?

How Many Calories Am I 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.  The remaining 20-40% of daily energy expenditure depends on your activity level throughout the day (which includes basic occupational activities as well as exercise and sport activities).

Factors that influence RMR:

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

 A quick and easy estimation of your daily calorie expenditure is to take your bodyweight in kilograms (divide your weight in lbs by 2.205) and times this number by 27.5 and this will equal roughly your daily calorie expenditure if you are sedentary.  This number will obviously increase if you are active whether it be occupational, training, or exercise.

Race Fuel

Runners, cyclists, and other endurance athletes are constantly looking for ways to improve their performance.  One of these ways is to use nutritional supplements to “boost” their energy and allow them to perform longer or harder before fatigue sets in.  Carbohydrates are the primary source of energy during exercise.  They can be stored in the liver and skeletal muscle as glycogen.  When exercise lasts longer than 60 minutes, glycogen stores begin to deplete. Without our number one supplier of energy during exercise fatigue will be soon to follow.  An easy way to help maintain carbohydrate levels, slow down the rate of glycogen depletion and aid in performance is to consume a carbohydrate/electrolyte solution.  Ideally this beverage should be 4-8% carbohydrate solution and you should try to consume 8-12 oz consumed every 10-15 min (around 30-60 grams of carbohydrates total).  This should help maintain carbohydrate levels within the body and help delay the onset of fatigue.  The beverage or food should be high in carbohydrate and well tolerated which can significantly boost the carbohydrate delivery to working muscles.  These sources of carbohydrates can include: sports beverages, crackers, bananas, carbohydrate gels, or bread to help supplement the body with additional sources of carbohydrates during exercise.

Another important, and often overlooked, ergogenic aid during endurance events is water.  During exercise in the heat, sweat rates of up to 1.5-2 L/hr have been reported. This can quickly lead to dehydration and ultimately a drop in performance.   Every 1% loss of your body weight as sweat, results in an increased heart rate of 7 beats per minute which can put additional stress on the cardiovascular system during exercise.  Therefore the number one priority during long distance events (especially in the heat) should be hydration.

A number of studies have also shown that caffeine ingestion can significantly increase fat mobilization (up to 18%) in the blood and allow it to be burned as fuel.  This allows carbohydrate stores to last longer and essentially “spare glucose” which can also delay the onset of fatigue.  Studies have shown increases of up to 20% in performance following caffeine ingestion.  Doses of 3 to 9 mg per kg of bodyweight or a total of 250mg have shown to be effective.

In summary, make sure you are consuming enough fluids and carbohydrates during bouts of long exercise.  Also, the addition of caffeine may help with sparing glucose and allow you to last longer before fatigue kicks in.

Nutrient Timing

It has long been accepted that exercise, specifically resistance training, is the primary way to increase muscle mass. However, an often-overlooked component of this process is the importance of nutrition and even more importantly, the timing of nutrients. Without the proper combination of nutrients, timing and exercise, one may not reach full potential. Before a workout, it is important to eat a well-balanced meal and consume plenty of fluids in order for energy stores to be full and ready for utilization. Ideally, this meal should be consumed 2-4 hrs before exercise and consist of 200-300g of carbohydrates, 30-40g of protein, and roughly 16 oz of water. Meals should also be low in fat and consist of familiar foods to promote gastric emptying and minimize discomfort. In addition, meals should consist of low glycemic index foods to prevent a rapid spike in blood sugar and insulin levels and provide a slower rise in blood sugar, resulting in longer lasting energy. During bouts of resistance exercise averaging an hour, nutritional supplementation is not as important as it is during long-duration endurance exercise because energy supplies are not. Therefore, proper hydration becomes the main focus during bouts of resistance training. Consuming 6-8 oz every 10 to 15 min should be sufficient to maintain proper hydration.

 Following exercise, nutrition should be the number-one priority to maximize muscle gains. There is an “anabolic window” of opportunity when the body is primed for muscle growth to occur if the proper nutrients are present. Following resistance exercise, the rates of protein synthesis and breakdown are elevated as a result of the stress placed on the muscles during the workout. If proper nutrients are not supplied to the muscle, muscle tissue will continue to be broken down without the desired increases in muscle synthesis. This is why post-exercise nutrition plays such a vital role. Carbohydrates and proteins are equally important because proteins provide the backbone for the synthesis of new muscle and carbohydrates replenish energy stores and increase insulin levels, which aids in the transport of nutrients into the muscle. Ideally a post-workout snack should be consumed within 30 minutes after exercise followed by a larger meal 2 hours later. The post-workout snack should consist of carbohydrates and protein in a 3:1 ratio. This should equate to about 1.5 g/kg of body weight for carbohydrates and .5 g/ kg for protein. In this case, the carbohydrates should be high glycemic index foods to promote a rapid rise in blood sugar and insulin, which will assist in the influx of nutrients into the muscle. Proper re-hydration should also be considered post-workout to compensate for any fluids lost during. Again, it is imperative that proper nutrient intake and timing be included in any training program to maximize results and help achieve one’s potential.

For further readings related to this topic:

• “International Society of Sports Nutrition position stand: Nutrient timing.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2575187/

•  “Effects of Supplement Timing and Resistance Exercise on Skeletal Muscle Hypertrophy.”

Medicine & Science in Sports & Exercise: November 2006 - Volume 38 - Issue 11 - pp 1918-1925