Understanding Fatigue After Daily Activities Dr Lorna Paul, Physiotherapist Reader in Rehabilitation
Fatigue after daily activities Post-exertional fatigue is one of the main symptoms of ME Lots of studies of exercise tests where people manage the exercise at the time but are not followed up for 24 or 48 hours later Post-exertional fatigue/malaise not just after strenuous activity Update of study funded by ME Association
Purpose of the study What goes wrong within the body which leads to post exertional malaise/fatigue in ME? Examining three things 1) HPA function 2) autonomic functioning 3) inflammatory response Examining these 3 things before and after 3 different tasks 1) cognitive task 2) cycling task 3) daily task (vacuuming)
Participant Groups 4 groups of people – 30 people in each group ME MS Post breast cancer (within one year of end of treatment) Healthy controls
Immunological response to exercise
Hypothalamic-Pituitary Axis (HPA axis)
What is cortisol? Cortisol (or hydrocortisone) is a steroid hormone released in response to stress increases blood sugar suppresses the immune system aids in fat, protein and carbohydrate metabolism
Autonomic Function The autonomic nervous system is part of the peripheral nervous system It controls many systems subconsciously eg The ANS affects heart rate, breathing, digestion, perspiration, size of pupils The hypothalamus ‘central control area’ for the autonomic nervous system Split into sympathetic and parasympathetic nervous systems
Immunological response to exercise
Immune response Immune cells produce cytokines which would be pro-inflammatory or anti-inflammatory
Each person attends four times Introduction and Induction 3 ‘fatiguing’ tests a)Computer based cognitive task b)Submaximal exercise bicycle task c)Standardised daily physical activity task (vacuuming)
Computer based cognitive task - PASAT Paced Auditory Serial Addition Test The PASAT is a measure of cognitive function that assesses auditory information processing speed and flexibility, as well as calculation ability. Single digits are presented every 3 seconds and the patient must add each new digit to the one immediately prior to it. The PASAT is presented on CD to ensure standardisation
Submaximal exercise bicycle task The Aerobic Power Index test is a submaximal exercise test on a static bicycle It consists of gradual increments in power output The test is stopped when people reach 75% of their predicted maximum heart rate (220-age)
Standardised daily physical activity task (vacuuming)
Outcome Measures – First visit Basic demographic details – age, height, weight, medications Questionnaires – eg. Hospital Anxiety and Depression Scale (HADS) Autonomic assessment
Outcome measures – Autonomic regulation
Outcome measures (cont) Heart rate and blood pressure monitoring during and after the task Questionnaires SF36 Checklist individual strength (CIS) - contains 20 items that measure 4 aspects of fatigue: 1. Subjective Fatigue; 2. Concentration; 3. Motivation; 4. Activity. Physical activity monitoring (7 days between tests)
Immunological markers - cytokines Bloods have been taken and frozen Still deciding on which cytokines to test Expensive tests to do!