The investigators aim to determine whether a wrist-worn accelerometer device is able to objectively measure physical activity, and whether it is an acceptable process for high-risk elderly patients prior to planned surgery. Accelerometers measure physical activity in 'counts' of activity, enabling them to record the total amount of activity in a given time period (e.g. number of steps per day), and also the time spent in various levels of intensity of activity. The investigators will ask study participants to wear an accelerometer around their wrist (like a wristwatch) for up to 14 days prior to their surgery. Participants will receive the same care as non-participants. Part of this routine medical care includes a preoperative review by a multidisciplinary team including specific personalised advice to optimise physical activity before surgery. The investigators will measure the impact that this existing intervention has on physical activity levels. Being more physically active is good for our health, and may be associated with a better recovery from surgery. In the future there may be methods of improving physical activity in the period of time before patients' surgery, which may improve their recovery from surgery.

In order to study this further, the investigators first need a robust and objective way of measuring physical activity. In current practice patients are asked to estimate how physically active they are on a day-to-day basis. This relies on how well they remember, and how good they are at getting it right and may not be accurate. The wrist-worn accelerometer is an objective method of measuring physical activity in patients, which not only offers greater understanding of the physical activity levels of elderly patients before a variety of operations, but also offers the opportunity to measure the impact of existing and potential future interventions to modify physical activity in the preoperative period.

Inclusion Criteria:

• Male or female aged 65 years or above
• Rockwood frailty score of ≥4
• Listed for elective major or complex surgery at Cambridge University Hospitals NHS Foundation Trust
• Capacity to consent and complete activity questionnaires
• Willing and able to wear accelerometer around wrist

Exclusion Criteria:

• Does not meet the inclusion criteria
• Participant refusal
• PRIME clinic appointment scheduled less than 72hrs after the nurse led pre-assessment clinic

The investigators are aiming to recruit approximately 50 high-risk patients aged 65 years and above, prior to major or complex elective surgery.

"High-risk" is determined by Rockwood Clinical Frailty Score ≥4. Major or complex surgery is defined in NICE guideline (NG45).