By The FIRM Master Instructor Rebekah Sturkie
Which is more effective: A sprint? A marathon? Or is it something else altogether? When plotting your course to weight loss, you can’t help but wonder if you should plan to work out harder or longer. The answer depends on your time and ability.
The hard workout: The sprint
A hard workout has a high level of intensity — physiological stress placed on the body. Generally speaking, this type of workout is also shorter in duration because it is nearly impossible to sustain a high level of intensity for a long period of time. A sprint is a good example of this — a short, fast race.
The speed and power of a sprinter comes from the use of fast-twitch muscle fibers. As their name implies, these muscle fibers fire rapidly with great force. But they also tire just as quickly. Fast-twitch fibers aren’t any stronger than other muscle fibers, but they use the anaerobic energy system. While both the anaerobic and aerobic systems use carbohydrates for fuel, the anaerobic system uses chemical compounds in the body, rather than oxygen, to break them down. These compounds release waste products that cause the muscles to fatigue completely within minutes — thus the short duration of a high-intensity activity.
The long workout: The marathon
We can probably all agree that a marathon is “intense,” but in reality, it requires a lower intensity physiologically than a sprint because of its duration. This endurance activity requires the use of slow-twitch muscle fibers. They fire more slowly than fast twitch and take a much longer time to fatigue. They rely on the aerobic energy system, which uses oxygen to break up carbohydrates (in the form of glycogen) for fuel.
Because oxygen is constantly being introduced into the body, the process can continue as long as the fuel source is available. Through proper diet and a controlled training regimen, we can increase the amount of glycogen our body can store. But, there is a limit and once it is depleted, fat becomes the primary fuel source. The process for turning fat into fuel is taxing to the body, however, and makes exercise more challenging. Even an elite marathon runner hits the wall at some point!
The slow workout: The neighborhood stroll
Both the sprint and the marathon sound pretty daunting. You were thinking more along the lines of the tortoise versus the hare, and you want to be the tortoise: “Slow and steady wins the race.” And, you might be basing this on the “fat-burning zone” theory: The idea that working out at a low intensity burns more fat. The reality is that a low-intensity workout burns a greater percentage of fat, not a greater amount.
For example, running burns about 35 percent of calories from fat. If you run for 50 minutes and burn 500 calories, that’s 175 fat calories burned. Meanwhile, leisurely walking burns more like 50-60 percent of calories from fat. For 50 minutes, with a total of 250 calories burned, that comes to 125-150 fat calories. So not only does running burn more fat calories, but it also burns more total calories. Does that mean you have to run for a good workout? Yes and no.
How to know which type of workout is best for you
The best workout is the one that you can (and WANT to) do consistently. If running is too painful, you are less likely to do it, which means zero calories burned. If walking is more your style, and you can do it regularly — daily would be ideal — then you can make a dent in your weight-loss goals over time. Another alternative is an interval workout — one that injects short bursts of high intensity (sprints, for example) into a moderate-level workout — which will allow you to burn an even higher number of calories but without having to increase the total time you workout or maintaining a high level of intensity throughout.
On the other hand, if you are like me and have a hectic, busy schedule, you may feel that finding the extra time in the day to devote to working out can be quite challenging. Try my personal approach, which is to focus on working at a high intensity for a short amount of time. I figure if I can get a thorough workout by kicking up the intensity, why not choose to do that and get it over with much sooner, rather than spend more time on an easier one?
The FIRM Master Instructor Team blog is shared courtesy of The FIRM Believers Club, an online community that helps you reach your fitness goals. With maximum-efficiency home workouts, support and motivation from The FIRM Master Instructors, daily tips, personalized workout rotation calendars, and access to other members through discussion boards, The FIRM Believers Club provides all the tools you need to get in the shape you want.