Learn how to utilize fat as fuel, improve efficiency and better gauge intensity by training in the right zones.
When you think of an easy run, thoughts of runners cruising down the sidewalk, rocking out to the beat in their headphones at a comfortable clip probably come to mind. Unknowingly, however, most runners don’t really run all that easy on their easy runs. After a few warmup miles, many runners start to feel good and begin pushing the pace without even realizing it. What started out as an easy run may end up being a push to simply get it over with as quickly as possible.
To help runners and other endurance athletes keep their easy runs easy and their hard workouts at the correct intensity, more and more coaches are relying on heart-rate training. Trapper Steinle, personal trainer, endurance coach and metabolic technician at Lifetime Fitness in Centennial, Colorado, encourages this type of training. He emphasizes that structured workouts in specific heart-rate zones will help increase an athlete’s metabolic efficiency, a fancy term meaning the body’s ability to burn fat as fuel.
During exercise, the body utilizes two primary sources of fuel, namely carbohydrates and fats. Unlike carbohydrates, which are limited and break down rather quickly, fat breaks down slower in the body and releases more energy. Plus, the amount of fat athletes can store is virtually limitless, even in the most slender of individuals. By teaching the body to burn more fat than carbohydrates, endurance athletes will be more efficient over longer distances. This translates to faster times and better performances. For many runners, it also means easy — but tedious — training.
To determine an athlete’s metabolic efficiency and identify their target heart-rate training zones, Steinle uses treadmill and bike tests. Athletes wear a heart-rate monitor, along with a mask that measures expired CO2 and O2. After a warmup, the athletes run or bike at an increasing level of effort until near exhaustion. The machine calculates ventilatory data and correlates metabolic efficiency with different heart-rate values.
Analyzing this data typically confirms the biggest problem for many athletes: they aren’t extremely efficient at utilizing fat as a fuel. When runners continually push their body hard in training, they teach their bodies to rely more on carbohydrates as fuel. This isn’t a desired adaptation according to Nicole Clark, personal trainer and triathlon coach in Westminster, Colo., who identifies training too hard as one of the biggest mistakes an athlete can make.
“Athletes are often feeling great in the beginning of their training block,” Clark says, “and it is easy to push too hard on light days, which can lead to injury, illness or overtraining.” To combat this problem, Clark advises all endurance athletes to train with a heart-rate monitor to gauge intensity.