On another thread we got into a discussion about Staci Stevens exercise programme for people with CFS, which is very interesting (its very much not Graded Exercise Therapy see below). Despite help from other people on that thread Im struggling to understand it (Ive got no background in exercise physiology etc.) and am starting this new thread hoping that others can help. Staci (who had/has CFS) and her team are university-based exercise physiologists (heres an audio-only podcast about their approach). She says that research shows that in CFS, the aerobic system of energy production is damaged and so aerobic exercise causes postexertional malaise. However, there are two systems of energy production - aerobic and anaerobic - and she believes that our anaerobic systems are working fine and can be trained so that we can get more function. When exercising, the anaerobic system is dominant for a short period before the aerobic system becomes the main contributor to energy production (a couple of minutes: see this graph). Athletes in non-endurance sports such as soccer, netball and so on are mostly using their anaerobic systems during their games. They therefore train their anaerobic systems using short periods of exercise of about 30 seconds (when the anaerobic system is still very dominant) and rest for about 90 seconds and then start again. Staci says that people with CFS can use similar anaerobic training to increase function. She used to offer, through Workwell at the Pacific Fatigue Lab, consultations where CFS people could get tested in their lab to find their anaerobic threshold and then get a tailored exercise programme. (Unfortunately theyre no longer staffed to do that). It typically started with extremely low reps and for v. short periods with long rests, as for the athletes. Lesley, on our other thread, describes what Staci advised for her: Just to clarify, Workwell would not let me start an exercise program if I was in a cycle of pushing and crashing. The pacing part came first. The initial program involved 4 repetitions of 4 exercises, using 2 lb weights and a rubber exercise band. If there was no exacerbation of symptoms after 2 weeks, I could add one additional repetition. This was not GET! Staci has written this summary for PWC about the training and this more technical journal paper for physical therapists. Theres a second element to this: using the anaerobic threshold for everyday pacing. Dr Lucinda Bateman on the IACFSME site (full text here) has written this: Staci Stevens, MS, an experienced CFS exercise physiologist in California, instructs her patients to wear a heart rate monitor with an alarm to notify them when the heart rate has climbed to a predetermined level. She measures a CFS patients anaerobic threshold objectively during graded cardiopulmonary testing, notes their heart rate at the anaerobic threshold, and then uses that heart rate value to estimate the anaerobic threshold during physical activity. It is typically somewhere between 90-110. (Lindas was 80!) Staci counsels patients not to exceed that heart rate during physical activity. When the alarm goes off, the patient stops the activity and sits down to rest. Whether avoiding a defect in oxidative metabolism, an escalation of orthostatic hypotension, or some other mechanism, this may be one tangible way of staying below the threshold of relapse and avoiding post-exertional malaise. Note that a rule-of-thumb formula often quoted to work out your anaerobic threshold heart rate is 220 minus your age, all times 0.6. So, if youre 50, that would be (220 50) x 0.6 = 102 beats/min. Id like to try Stacis approach both to anaerobic training and using the anaerobic threshold to avoid PEM but Im confused about some things: *When I'm just sitting, am I using anerobic or aerobic energy production? Or what? *If Im walking with a heart rate below my anaerobic threshold, again, what system of energy production am I using? *If I were to train using the work-interval system (anaerobic work/long rest, repeated), would that increase the length of time that my anaerobic system would be dominant? *How much time is is possible to extend any useful dominance of the anaerobic system, given that it seems to be pretty much gone in 5 mins? *Is anaerobic training "just" for strength training? Any exercise buffs out there who remember this stuff?