Understanding Patterns of Fatigue in Health and Disease

Inclusion Criteria:

* For all groups, participants will be included if they are willing to participate in intermittent ecological momentary assessments of fatigue, to wear an ECG patch, to provide questionnaire responses at baseline, and the end of the study, and to participate in an end of study interview.

Inclusion Criteria for Group A, individuals with myeloma

* A confirmed diagnosis of myeloma
* Has experienced fatigue that is perceived by the participant to be worse than "normal tiredness" and that they associate with myeloma or treatment for myeloma

Inclusion Criteria for Group B, heart failure

* A formal diagnosis of heart failure
* All stages of heart failure and all aetiologies and with no specific ejection fraction cut-off
* Has experienced fatigue that is perceived by the participant to be worse than "normal tiredness" and that they associate with their cardiac disease or its treatment

Inclusion Criteria for Group C, long COVID

* Experiencing fatigue that is perceived by the participant to be worse than "normal tiredness", with or without other physical or psychological symptoms that developed during or after an infection consistent with COVID-19
* The fatigue (plus or minus any other symptoms) has continued for greater or equal to 12 weeks, and is not explained by an alternative diagnosis

Inclusion criteria for Group D, control group

• Individuals aged 18 years or over without the disease conditions specified in Groups A to C

Exclusion Criteria:

* Exclusion Criteria Applying to all participants:

  * Difficulty communicating in English
  * Adults lacking capacity to consent
  * Under 18 years of age
  * Declines to participate
  * Under investigation for or starting treatment for an endocrine, metabolic, or thyroid condition where the participant has not been established on a stable therapeutic dose of a licensed therapy for that condition
  * A confirmed diagnosis of sleep apnoea or narcolepsy
  * HADs depression and anxiety score at baseline greater than 8 on the depression questions, which might indicate untreated or undertreated depression
  * Shift work that involves overnight working between the hours of 9pm and 9am

We will not exclude patient participants in groups A to C based on the type of prescribed medications that they are taking. Instead, this will be carefully documented.

For Group A, myeloma

* Uncontrolled hypercalcaemia
* Current or previous diagnosis of heart failure or long COVID
* An active primary cancer diagnosis other than myeloma Group B Heart Failure
* A current or previous diagnosis of myeloma or long COVID
* Active cancer Group C, long COVID
* A current or previous diagnosis of myeloma or heart failure
* Active cancer Group D, Control group
* Presence of myeloma or another active cancer, heart failure, or long COVID
* One or more chronic medical conditions which are unstable, poorly controlled, AND perceived by the individual to be causing fatigue
* Persistent or severe fatigue symptoms that are perceived by the individual to be worse than "normal tiredness"
* Taking sedating medications to manage anxiety or insomnia including but not limited to benzodiazepines or "Z" drugs, zopiclone, zolpidem, and others in this British National Formulary Class.