Bell Ability Scale
The fatigue in CFS is both mental and physical. For some sufferers, the physical is the greatest burden and for others, the mental fatigue is most troublesome. This scale was developed by Dr David Bell  as a clinically useful way to assess response to treatment - it combines physical and mental acitivity with levels of wellness. This is not entirely satisfactory because different people suffer in different ways but it does give an idea of the level of disability.
100: No symptoms with exercise. Normal overall activity. Able to work or do house/home work full time with no difficulty.
90: No symptoms at rest. Mild symptoms with physical activity. Normal overall activity level. Able to work full time without difficulty.
80: Mild symptoms at rest. Symptoms worsened by exertion. Minimal activity restriction needed for activities requiring exertion only. Able to work full time with difficulty in jobs requiring exertion.
70: Mild symptoms at rest. Some daily activity limitation clearly noted. Overall functioning close to 90% of expected except for activities requiring exertion. Able to work/do housework full time with difficulty. Needs to rest in day.
60: Mild to moderate symptoms at rest. Daily activity limitation clearly noted. Overall functioning 70% to 90%. Unable to work full time in jobs requiring physical labour (including just standing), but able to work full time in light activity (sitting) if hours are flexible.
50: Moderate symptoms at rest. Moderate to severe symptoms with exercise or activity; overall activity level reduced to 70% of expected. Unable to perform strenuous duties, but able to perform light duty or deskwork 4 - 5 hours a day, but requires rest periods. Has to rest/sleep 1-2 hours daily.
40: Moderate symptoms at rest. Moderate to severe symptoms with exercise or activity. Overall activity level reduced to 50-70% of expected. Able to go out once or twice a week. Unable to perform strenuous duties. Able to work sitting down at home 3-4 hours a day, but requires rest periods.
30: Moderate to severe symptoms at rest. Severe symptoms with any exercise. Overall activity level reduced to 50% of expected. Usually confined to house. Unable to perform any strenuous tasks. Able to perform deskwork 2-3 hours a day, but requires rest periods.
20: Moderate to severe symptoms at rest. Unable to perform strenuous activity. Overall activity 30-50% of expected. Unable to leave house except rarely. Confined to bed most of day. Unable to concentrate for more than 1 hour a day.
10: Severe symptoms at rest. Bed ridden the majority of the time. No travel outside of the house. Marked cognitive symptoms preventing concentration.
0: Severe symptoms on a continuous basis. Bed ridden constantly, unable to care for self.
Please, note that "desk work” includes everyday tasks such as sitting at a table to eat or read.
- Mitochondrial Function Profile. This is a very useful test for people wishing to claim benefits because it gives us an objective measure of fatigue. This was demonstrated in the paper I co-authored jointly with Dr John McLaren Howard of Acumen and Prof Norman Booth of Oxford University and published in the International Journal of Clinical and Experimental Medicine. The full text of the paper can be accessed here: Chronic Fatigue Syndrome and Mitochondrial Dysfunction.
- David S Bell. ‘The Doctor’s Guide to Chronic Fatigue Syndrome’; Addison-Wesley Publishing Company, Reading, Mass.
Sarah Myhill Limited :: Registered in England and Wales :: Registration No. 4545198
Registered Office: Upper Weston, Llangunllo, Knighton, Powys, Wales LD7 1SL, UK. Tel 01547 550331 | Fax 01547 550339