Fitness in general

Many people will have their own idea of what they believe physical fitness to be. It can be defined as a state of health and well-being and, more specifically, the ability to perform aspects of sports, occupations and daily activities. Well-being includes physical as well as mental health and eating well is as important a contributor to well-being as is physical activity.

Increasing physical activity has the potential to improve the physical and mental health and well-being of individuals, families, communities and a nation as a whole. For example, according to physical activity guidelines for adults from the UK Chief Medical Officers, adults should aim to take part in at least 150 minutes of moderate intensity physical activity each week, in bouts of 10 minutes or more. Moderate intensity physical activities, such as brisk walking or cycling, cause adults to get warmer and breathe harder and their hearts to beat faster, but they can still carry on a conversation.

Fitness and disease

There is growing evidence for the positive role of physical activity during and after treatment for a variety of different chronic long term conditions and diseases. In many acute conditions pre-emptive fitness levels can have a positive effect on rehabilitation as well as being beneficial for many types of major surgeries and general anaesthesia.

Physical activity can improve, or prevent decline of, fitness and assist in the improvement of physical function and fitness. Physical activity may be broadly and generally defined and/or include specific and targeted exercises in physiotherapy.

Evidence suggests that improved fitness and physical activity may reduce the risk of disease recurrence and potential relapse. Good levels of fitness and physical activity can help maintain independence and promote well-being at advanced stages of illness.

It is advisable to gradually build up to the health-related physical activity guidelines for the general population. The evidence shows that if an activity recommendation is carefully tailored to the individual, it is likely to have a positive impact.

Fatigue is a common symptom of many diseases and long term conditions and/or treatments. The exact causes of fatigue in patients is often unknown: it may be caused by the disease itself or its treatment, or a combination of both. It may be the result of psychological and physiological responses, or it may result from deconditioning due to further reduction of physical activity. There is evidence that exercise is beneficial in the management of fatigue, including treatment periods.


There is a growing body of evidence in support of optimising health and fitness of people before the start of acute treatments. This is true for different treatment modalities (surgery, radiotherapy, chemotherapy), for malignant and non-malignant conditions, and for patients of all ages.

Such attempts are known as prehabilitation (or prehab, for short). Prehabilitation aims to prevent or reduce the severity of anticipated treatment-related impairments that may cause significant disability. Preliminary evidence suggests that following an appropriate exercise programme before treatment (prehabilitation) leads to increased cardiorespiratory fitness, fewer postoperative complications and shorter hospital admissions.

The exact nature of such tailored pre-treatment exercise schemes is defined by the underlying condition and the planned treatment. For example, optimised schemes ahead of elective orthopaedic surgery such as knee or hip replacement in otherwise healthy people will be different from those that are most suitable for people with multiple co-morbidities ahead of major maxillofacial surgery (surgical prehabilitaton schemes are well established in orthopaedic surgery in many places).

Any attempts to engage with pre-treatment improvement of fitness should see prehabilitation in conjunction with efforts to support cessation of drug abuse as the extensive use of many recreational drugs negatively interferes with treatment(s) and/or recovery.

Further reading: Recreational drugs