Cancer treatments such as chemotherapy often affect healthy cells as well as the cancer cells and this can lead to side-effects such as low blood counts - anaemia. This can cause severe fatigue, shortness of breath and brain fog and may need regular blood transfusions. Their quality of life (QoL) is often very poor during treatment because of these side effects, and it is hard to deal with.

Doctors use blood tests to decide whether a patient is well enough for treatment and when to start treatment. However, blood tests do not tell us how a person feels, and it is not the same in everyone. We need a better way for doctors to monitor patients' QoL and these symptoms so that they are physically and emotionally able to continue their treatment. It is hard for doctors to accurately assess this through speaking to their patients and doctors do not record or discuss these effects of treatment very well with patients.

The aim of this study is to better understand how people feel during their treatment and how we can best use blood transfusions to maintain QoL.

80 adult patients who are starting blood cancer treatments will be asked to answer questionnaires about how they are feeling and their symptoms during their treatment. Participants will be asked to wear a smartwatch to measure their physical activity levels. Activity data collected will then be compared with their reported QoL and blood counts to help us understand when patients can tolerate difficult treatments the best and how blood transfusions affect this.

Patients, their family and carers will be invited to take part in an interview to understand their views on how we can improve their care, QoL and access to transfusions.

A better understanding of the impact of low blood counts on QoL can help us use blood transfusions to benefit patients' lives. This work will better match transfusions to individual peoples' needs and therefore 'personalise' blood transfusion care.

Inclusion Criteria:

• Patients aged ≥18 years with WHO-defined MDS or mixed myeloproliferative/myelodysplastic neoplasm overlap syndromes (MPN/MDS), myeloma and AML
• Intention to undertake disease modifying treatment
• Life expectancy ≥ 6 months
• Able to complete quality of life questionnaires
• Willing and able to provide informed consent for participation in the study
• Willing to receive blood products as part of normal NHS care

Exclusion Criteria:

• Poor performance/functional status (Eastern Cooperative Oncology Group system ECOG ≥3)
• Participants with known arrhythmias or other significant cardiological conductivity disorders
• Patients with severe comorbidities
• Patients with known skin allergies or conditions that in the opinion of the investigator would compromise the safety of the patient or quality of the data
• Hospitalised patients
• Patients currently participating in another interventional clinical study
• Patients with a pacemaker or implanted cardioverter defibrillator or any cardiac implanted device

Participants will be patients who have been diagnosed with haematological malignancies (MDS, AML and myeloma)