Weblogic

As was mentioned in last month’s newsletter, even in light of upcoming holiday temptations, this is the time of year to really focus on eating properly and, maintaining (or not gaining) weight.  However, eating properly also means getting in enough, and the proper, calories (energy) to perform well in workouts.    If you are looking to maintain your weight, then you can maximize your performance by making sure you are consuming a number of calories which is roughly equivalent to what you are burning.  However, if weight loss is your primary goal then you should expect some decreases in performance during some of your workouts since you are (presumably) running a calorie deficit.  In this case, the lack of performance in workouts is justified since, over the longer term, performance should also improve as a result of the lost weight.  In either case, the question is: How do I know how what the appropriate number of calories is?

A few people can do this by instinct and by simply watching a scale.  If you see the scale go up, then you cut back on your food intake.  If it goes down and you continue to feel reasonably well, then you keep on that program.  If weight drops but you start to feel fatigued from working out (or even every-day activities), then, you should consider adding additional calories (start eating a bit more) to prevent that from happening.

Most people struggle with instincts though and need to step back and rely upon a more methodical approach.  To do that you need to actually track “calories in” and “calories out.”  Bottom line: to lose weight, you need to burn more than you intake. 

There are a number of easily accessible calories counters out there (see Fitday.com or trainingpeaks.com) to help you add up the “calories in.”  But, calculating the calories burned is not so easy. 

Basically, you need to count the calories that your body burns at rest, during normal daily activities and during exercise.  The total of all these is your “calories out” for any given period.  All of these can be measured reasonably accurately using a metabolic cart (the machine that is used during VO2 submax and max tests).  However, many don’t want to spend the money or take the time to do such a test (and this blog was inspired by such a person).  For those people, there are still ways to estimate your calories out, based on formulas derived through scientific research. 

One such formula is contained in the blog linked below:

 http://www.triathlontrainingblog.com/?page_id=483\

Here you will find a calculator designed to help calculate calories burned in a workout.  The calculator uses the formulas (as posted on the link) below, depending on whether you know your VO2max (either from lab or field testing).  It is worth noting that these formulas have been derived from research that is apparently relied upon by POLAR to calculate calories burned in its heart rate monitors:

Using VO2max

   Men: C/min = (-59.3954 + (-36.3781 + 0.271 x age + 0.394 x weight + 0.404 x VO2max + 0.634 x HR))/4.184

   Women: C/min = (-59.3954 + (0.274 x age + 0.103 x weight + 0.380 x VO2max + 0.450 x HR)) / 4.184

Without VO2max

   Men: C/min = (-55.0969 + 0.6309 x HR + 0.1988 x weight + 0.2017 x age) / 4.184

   Women: C/min = (-20.4022 + 0.4472 x HR + 0.1263 x weight + 0.074 x age) / 4.184

weight is in kg

Even when using formulas based on years of research, there are some important caveats, or things to remember.  Formulas are based on averages.  They take real data from a lot of subjects and then derive a mathematical equation to "best fit" that data.  Take that equation, build a calculator and, voila, you have a way to estimate calories burned.  For physiology, this works well in some cases and not so well in others.  If you are an average person then the formula will work great for you.  The further from average you are, the more incorrect the numbers you get from the formula will be when applied to YOU.  For example, if the above formulas were developed with data from people running 8-10 minutes per mile, then they are not going to be accurate at all for runners who regularly run 6-8 minutes per mile.  

In not so many words, you can be way off if you incorrectly and even correctly use these formulas.

Since this is such a good question and there is more to say about the formula you should use, I’ll write a more complete article in our November newsletter (going out soon) for those that are interested.  Sign up, if you have not already and I’ll explain further.