After completing an MBS Fitness training program and right before each of the athletes run their marathon (or other race), I make a prediction on how long it will take them to complete the race.  Many of these athletes are surprised at the accuracy of these forecasts.  In the last training cycle, 90% of the athletes came within five minutes of the time I predicted.  The predictions are not based on magic or the luck of the Irish.  The predictions are based on science, the same science that have led doctors and scientists to recommend you raise your heart rate over a target rate at least three days a week for at least 30 minutes in order to maintain health and prevent disease.  The science is based on correlating your body’s capacity to expend energy and do work (read exercise) with its ability to utilize oxygen efficiently.  The measure of the rate of energy expended while doing work or exercise is known as metabolic equivalents or METS.  Understanding your METS will not only help you understand how to prevent disease, doing so can also help you train more effectively.

Exercise produces heat.  We all get hot and sweaty after we run a certain distance.  The amount of heat produced is directly proportional to the rate of energy expended, again measured in METS.  At rest, everyone expends energy at the same rate, measured as one MET, regardless of age or fitness level.  As you expend energy, your body also uses oxygen.  At rest, everyone uses the same amount of oxygen for each kilogram (or pound) of body weight.  We all use 3.5 ml/kg/min.  That’s 3.5 milliliters (metric measurement of volume of oxygen used) per kilogram (metric measurement of standardized body weight) per minute.  This rate of oxygen consumption at rest is equivalent to the rate of energy expenditure of one MET (3.5 ml/kg/min = 1 MET). 

What is unique about each person is the rate he/she can expend energy and his/her ability to utilize oxygen, given a certain workload.  Both are directly correlated and dependent on his/her fitness level. For example, if Mary and John run five miles and Mary is able to process more oxygen than John in that distance, Mary is more fit, can sustain higher METS and has the capacity to complete the five miles faster than John.

Knowing your body’s maximum METS—it’ s maximum rate of energy expenditure and equivalent maximum capacity for utilizing oxygen known as “VO2 max” – is important to building an effective fitness program.  Knowing how to improve your METS and VO2 max and utilizing a training program based on these measures can be the difference between training smart and risking over- or under-training.  Most amateur athletes are able to sustain 60% - 80% of their maximum METS or VO2 max while exercising over a period more than 30 minutes.  The percentage one can sustain is based on the individual’s tolerance level with that stress on his/her body.  Professional athletes typically are able to sustain more than 90% of their VO2 max.  Optimum improvement occurs when you exercise at around 80% of your maximum METS and VO2 max.

Let’s use an example to clarify how this all works.  If an athlete, Sara, runs a fitness test and I determine her maximum rate of expending energy is 10 METS (and her equivalent VO2 max is 35 ml/kg/min), I can predict that she would be able to run at a 12-14 minute/mile pace for a sustained amount of time.  The 12 – 14 minute/mile pace is taken from Sara being able to expend energy at the rate of about 6 - 8 METS or between 60% and 80% of her max METS or VO2 max.  The guideline for Sara is that she has the aerobic capacity to run the marathon in about 5 hours and 38 minutes, at the time of the fitness test.  Successfully completing a marathon-training program would mean increasing Sara’s maximum METS, conditioning her muscles to completing the long distance and decreasing the time she is capable of completing the race.

Scientist have also found that individuals expending energy at the rate of 6-8 METS at least three days a week for 30 minutes are more likely to prevent disease and live healthier.  This is the science that has led them to their recommendation for the minimum amount of exercise to stay healthy.

So, know your METS, stay healthy and train smarter.

Coach Murphy