If you’ve been diagnosed with ME/CFS (myalgic encephalomyelitis / chronic fatigue syndrome) for even a short time, you’ve probably been advised to stay within your energy envelope. But do you really know what that means?
The energy envelope theory is a self-management tool designed to help people with ME/CFS reduce their symptom severity and cut down on the frequency of relapses. You might be surprised to learn that the energy envelope theory was first developed and tested by renowned ME/CFS researcher Leonard Jason, PhD. According to Jason’s theory, when ME/CFS patients expend more energy than they perceive they have, the result will be post-exertional malaise  (PEM) and greater overall disability.
Post-exertional malaise––a worsening of symptoms following even minimal physical or mental exertion––is the hallmark ME/CFS symptom , differentiating it from other types of chronic fatigue. It can be difficult to pinpoint exactly what activity or exertion triggered the PEM since the onset of PEM is frequently delayed, often occurring two or more days after the initial trigger. This makes the use of the energy envelope theory even more important as a preventative tool.
The Origins of the Energy Envelope Theory
Jason describes how the energy envelop theory came about in a 2013 article published in the journal Fatigue . Following are excerpts from that article:
Beginning in 1993, our research team began collecting behavioral time-series data to better understand the relationships between activity and fatigue in patients with ME/CFS. It was clear to us that some individuals had high levels of fatigue that were influenced by how much activity they engaged in, and we wanted to better understand this relationship. We hypothesized that by limiting levels of activity in order to reduce high levels of fatigue and other symptoms, positive gains may occur for the patients…
In our next study , conducted in 1996, [we] collected behavioral data in which participants with ME/CFS were asked to rate perceived or available energy and the amount of energy expended. We found a significant relationship between current fatigue level and the amount of energy that participants perceived they had expended two days prior. In a different data set, results indicated that actigraphy data (from actigraphs that electronically monitor activity) were significantly related to self-reported indices of expended energy…
During 1995 and 1996, we began further developing our rehabilitation ideas of energy conservation and the use of moderation for patients with ME/CFS. Our first publications on the Energy Envelope Theory appeared in 1997 and 1999 . This theory suggested that by maintaining expended energy levels within the “envelope” of perceived available energy levels, patients with ME/CFS would better be able to sustain physical and mental functioning while reducing symptom severity and the frequency of relapses. In a later correlational study , we found that the individuals with ME/CFS experienced a range of symptoms and disability when they extended beyond their energy envelopes. This evolving approach suggested that patients could be taught to assess their perceived available energy levels on a daily basis and use that level to gauge their energy expenditures for each day.
In a 2009 study, Jason and his team further tested the energy envelope theory when they divided 114 patients with ME/CFS into two groups: those who were able to keep their expended energy close to their available energy and those who were not. As you can see in the two graphs below, those who were able to stay within their energy envelopes experienced significantly improved physical functioning and significantly reduced fatigue severity.
Implementing the Energy Envelope Theory
The energy envelope theory is basically a form of pacing  – not something that comes naturally to most of us. Does this sound familiar? You have a “good” day––a day when you feel a little better than you have in quite awhile––and you try to get everything done that you had to put off when you weren’t feeling well. In fact, it feels so good to finally be accomplishing things, you push yourself beyond what you know you should – until the fatigue really starts to set in and you crash. Then it takes you several days or even weeks to recover.
This push–crash cycle is not unusual for people with a chronic illness like ME/CFS to fall into, but it’s totally counter-productive. Not only does it make you feel bad in the short term, it can actually make your symptoms worse over the long term. On the other hand, when you learn to stay within your energy envelope on a daily basis, not only will you avoid relapsing due to PEM, but you may gradually find your energy envelope expanding to allow you to be more active.
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ME/CFS expert Dr. Sarah Myhill says , “Rest is the single most important factor in allowing chronic fatigue syndrome sufferers (CFSs) to get better.” Staying within the energy envelope allows your body to get the healing rest it so desperately needs.
It may take some trial and error, but with practice you can learn to assess what your available energy is each day. If you’re having trouble figuring it out, it might help to visualize your limits. Here are some energy envelope visualizations others have suggested:
- The Energy Bank Account – One suggestion offered by Bruce Campbell, PhD, Executive Director of CFIDS & Fibromyalgia Self-Help , is to think of your energy limits as a bank account  with a low balance. If you spend more than you have, you’ll overdraw your account, resulting in big service charges and costing you more in the long run. Likewise, if you overdraw your energy account, you’ll have to deposit a lot more into your account in the form of rest to cover the overdraft.
- The Bowl of Marbles – In her book Your Personal Guide to Living Well with Fibromyalgia, Linda Jean Frame suggests you imagine your available energy as a bowl of marbles, with each marble representing a small amount of expendable energy. Each time you exert yourself physically, mentally or emotionally, remove one or more marbles. When your bowl is empty, it’s probably time to rest. This visualization can help you prioritize your activities and learn to save energy for things that are most important to you.
- The Spoon Theory – Developed by Lupus patient Christine Miserandino, the Spoon Theory  involves picturing your available energy as a fixed number of spoons. Similar to the bowl of marbles, every time you exert yourself, you take away one or more spoons. When you run out of spoons, your day is done and your only option is to rest.
Regardless how you choose to think of your available energy, the important thing to remember is that your supply is limited. You need to budget what you have and dole it out carefully and thoughtfully. If in doubt, rest. An extra hour of rest won’t hurt you, but an extra hour of activity when your energy supply is depleted can cost you dearly.
The Energy Envelope Theory: What It Is and Is Not
Just to be clear, the energy envelope theory is not an ME/CFS treatment , and it’s certainly not a cure. It is simply a self-management tool that can help you better cope with living with ME/CFS. Utilizing the energy envelope will enable you to live a more balanced life by helping to prevent relapses. As an added bonus, you may find that over time your available energy supply will gradually increase, giving you a bigger energy envelope to work with.
Karen Lee Richards is ProHealth’s Editor-in-Chief. A fibromyalgia patient herself, she co-founded the nonprofit organization now known as the National Fibromyalgia Association (NFA) in 1997 and served as its vice-president for eight years. She was also the executive editor of Fibromyalgia AWARE magazine. After leaving the NFA, Karen served as the Guide to Fibromyalgia and Chronic Fatigue Syndrome for the New York Times website About.com, then worked for eight years as the Chronic Pain Health Guide for The HealthCentral Network before coming to ProHealth. To learn more about Karen, see “Meet Karen Lee Richards .”
Jason LA, Tryon W, Taylor R, King K, Frankenberry E, Jordan K. Monitoring and assessing symptoms of chronic fatigue syndrome: Use of time series regression. Psychological Reports. 1999;85:121–130. doi: 10.2466/pr0.19126.96.36.199 
King CP, Jason LA, Frankenberry EL, Jordan KM, Tryon W. Think inside the envelope. The CFIDS Chronicle. 1997;10:10–14.
Jason L, Melrose H, Lerman A, Burroughs V, Lewis K, King C, Frankenberry E. Managing chronic fatigue syndrome: Overview and case study. American Association of Occupational Health Nurses Journal. 1999;47:17–21. https://www.ncbi.nlm.nih.gov/pubmed/10205371 
Jason LA, Muldowney K, Torres-Harding S. The energy envelope theory and myalgic encephalomyelitis/chronic fatigue syndrome. American Association of Occupational Health Nurses Journal. 2008;56:189–195. https://www.ncbi.nlm.nih.gov/pubmed/18578185 
Jason LA, Benton M, Torres-Harding S, Muldowney K. The impact of energy modulation on physical functioning and fatigue severity among patients with ME/CFS. Patient Education and Counseling. 2009;77:237–241. doi: 10.1016/j.pec.2009.02.015