Many people who turn to exercise to lose fat do so with a burst of enthusiasm that tapers off rapidly when results are not as fast as they would expect, when discomfort is greater than anticipated, or when they perceive a time commitment to be longer than first expected. Fortunately, low intensity is the way to go for beginning clients whose main goal is fat reduction, and it can be done just about every day!
Few things are as off-putting as the sense of failure when first attempting something. A natural tendency is to add more intensity to the effort (ever try smacking an appliance in an effort to get it working?) Yet going at it hard and heavy can often lead to frustration for the beginning client. So it can be a somewhat counterintuitive concept to grasp that when fat loss is a stated goal, it is low intensity that is a good way to go.
Tipping the Balance
It’s common for a beginning client whose primary goal is fat loss to have a history of prolonged periods of little to no real aerobic activity. This means that he or she has a relatively inefficient ability to mobilize and use energy from fat. However, their bodies are typically quite efficient when it comes to using carbohydrates for energy, which does little for reducing fat storage. It is possible to largely avoid this phenomenon and tip the balance to a carbohydrate metabolism by having the client use very low intensity levels when beginning an aerobic exercise program. To address glucose metabolism, the resistance exercise prescription can be called upon to “do the heavy lifting,” so to speak.
Intensity can be a difficult phenomenon to rate: What may qualify as intense for one person may rate as a “meh” for another. Fortunately, tests such as the Rating of Perceived Exertion (RPE) exist as a way to quantify intensity in exercise and athletic training. The original scale ranges from 6-20, with a 6 registering as no exertion all the way to a 20, or maximal exertion.
Another important quantitative measure is target heart rate. This is commonly determined by using an equation known as the Karvonen Formula:
Target Heart Rate = ((max HR − resting HR) × %Intensity) + resting HR example
Best results are achieved by measuring both resting and maximum heart rate.
If a heart rate monitor is used, it should be possible to observe a slow, progressive increase over the course of several minutes of exercise until the heart rate reaches between 60%-70% intensity based on the Karvonen formula. This should be coupled with a progressive increase in the client’s respiration. These breaths should not become so labored as to keep the client from speaking comfortably within the 60%-70% intensity range, however.
With a bit of practice, most clients should be able to use the RPE scale as a means of monitoring their level of intensity at aerobic exercise, and this can lessen the need for heart rate measurements. For the fat reduction client, an RPE of 11 (fairly light), plus or minus one, represents a stable, practical level. At this level, the client should not exceed his or her body’s capacity to provide enough energy through fat while also minimizing the body’s use of glycogen through glycogen conversion.
Whatever method is used, when establishing an intensity range for any client, keep in mind factors such as age, cardiorespiratory function, and level of aerobic conditioning, and be ready to adjust accordingly. As the client’s cardiorespiratory efficiency improves, the intensity of the exercise can progress as can be tolerated.
Fortunately, there are a number of common activities that involve fairly low-level aerobic intensity. Some examples include cycling and stationary cycling, walking—even bouncing on a mini-trampoline! Intensity levels for these activities are in general easy to control, can be progressed without particular difficulty, are typically low impact, and generally require learning few (if any) new skills. For these reasons alone, they can be practiced and enjoyed by a variety of clients for a broad range of goals.
The other part of the equation is duration. Typical recommendations for aerobic activity duration range from 15 minutes to an hour per session. However, the sessions for the fat reduction client can veer toward the upper end of this range, if the intensity of the exercise is maintained at the lower part of the prescribed heart rate intensity range.
As a practical matter, this type of exercise can be performed on a daily basis, assuming that the client is not on a caloric restriction diet below a maintenance level. This is also in keeping with reality—not everyone has a schedule that permits long hours in the gym, but many people can find the time to perform some form of low-intensity aerobic exercise each day.
This prescription can also be applicable to seniors and to strength athletes who may be have an interest in fat reduction and the cardiorespiratory benefits that result from this type of activity.
- Low intensity (60%-70% exercise target rate based on the Karvonen formula)
- High frequency: Fat reduction clients can and should exercise more often
- Long Duration: Up to one hour or slightly longer at very low intensity levels
- Choose types of exercises that can be performed with low impact, at low intensity, for relatively long periods of time, that require minimal coordination, and that are repetitive or even rhythmic in nature.
For fat loss and the beginning client, ‘low’ and steady can win the race!
1. The National Federation of Professional Trainers. Personal Trainer Certification Manual. 5th Ed. Lafayette, IN: NFPT, 2008.
2. Borg’s Perceived Exertion and Pain Scales. Champaign, IL: Human Kinetics; 1998