Understanding Fatigue After Daily Activities

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Understanding Fatigue After Daily Activities

• Dr Lorna Paul,
• Physiotherapist
• Reader in Rehabilitation

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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

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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)

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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

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Immunological response to exercise
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Hypothalamic-Pituitary Axis (HPA axis)
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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

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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

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Immunological response to exercise
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Immune response
Immune cells produce cytokines which would be
pro-inflammatory or anti-inflammatory
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Each person attends four times

• Introduction and Induction
• 3 fatiguing tests
• Computer based cognitive task
• Submaximal exercise bicycle task
• Standardised daily physical activity task
  (vacuuming)

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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

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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)

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Standardised daily physical activity task
(vacuuming)
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Outcome Measures First visit

• Basic demographic details age, height, weight,
  medications
• Questionnaires eg. Hospital Anxiety and
  Depression Scale (HADS)
• Autonomic assessment

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Outcome measures Autonomic regulation
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Outcome measures (cont)

• Heart rate and blood pressure monitoring during
  and after the task
• QuestionnairesSF36Checklist 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)

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Immunological markers - cytokines

• Bloods have been taken and frozen
• Still deciding on which cytokines to test
• Expensive tests to do!

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• Lorna.Paul_at_glasgow.ac.uk
• 0141 330 6876