This is an observational, non-interventional study to assess the equivalence of wearable monitors with formal CPET testing for the prediction of physiological reserve before major surgery.

This project will exploit the rapid development of wearable technology to allow perioperative risk prediction to become logistically easier, cost effective and used more broadly. It will use low cost wearable technology to complement or act as a surrogate to complex CPET testing performed for perioperative risk stratification. The data gained from a Garmin Vivosmart HR+ wearable device, will be used in the community by patients awaiting surgery, and will be correlated with key CPET indices including anaerobic threshold and peak VO2. Ultimately, this study aims to assess whether wearable technology can provide the data needed for the formation of prediction models to risk assess perioperative outcomes in patients undergoing high-risk elective surgery. In addition, an International Physical Activity Questionnaire (IPAQ) will be completed to compare the activity captured with self-reported activity. This will be combined with frailty scores and handgrip strength as is routinely collected during CPET. Finally, a saliva based genetic analysis will be conducted on genetic variations known to be of significance in critical illness and response to physical stress. This will be delivered by a laboratory (Fitness Genes) that has developed a bespoke panel of genetic markers ideally suited to this patient cohort.

Inclusion Criteria:

• Aged 18 years or older with capacity to consent
• Clinical indications for planned CPET testing before planned major elective surgery

Exclusion Criteria:

• Atrial fibrillation
• Nickel allergy
• Unable to wear a watch
• Unable to conduct CPET
• Pregnancy

Recently, low-cost, wearable activity monitors have become very popular. They can record lots of information about a person's general health and activity. In this study, we would like to see if an activity monitor can help predict a person's risk of developing complications after having major surgery.

Only on request.