Demographic research shows that the proportion of older people in society is increasing. More people age well, but there are also more people getting old with disability and multimorbidity. The large diversity in functioning illustrates the heterogeneity of aging. Accelerated aging may lead to frailty, which is a geriatric syndrome, often used as a marker of biologic age and associated with decreased physiologic reserves, increased vulnerability and the risk of adverse health out- comes. Frail elderly people are frequent visitors within emergency hospital care and physical decline is common. Unfortunately, elderly patients with substantial multimorbidity are often excluded from clinical trials.

Physical fitness comprises a set of measurable health- and skill-related outcomes, such as cardiorespiratory endurance and muscle strength. A decrease in physical fitness may affect the prognosis negatively. However, previous research indicates that it may be possible to reverse frailty and improve physical fitness. It is therefore of the utmost interest to identify frailty and study how care is best provided, in order to prevent, reduce and postpone adverse health consequences.

The overall aim of this thesis is to study physical fitness in a group of frail elderly patients, within clinical hospital health care. The patients’ physical fitness will be evaluated and compared in different care settings during and after hospitalization. The aim is also to study the long-term consequences of changes in physical fitness in relation to mortality. To better understand the underlying factors for partici- pation in physical activity and exercise, patients’ perceptions of the phenomena will be explored.

This thesis consists of four papers based on two studies comprising frail elderly patients with substantial multimorbidity, in connection with an in-hospital episode.

Paper 1 was an observational study with a cross-sectional design (n=408). Different components of physical fitness were measured during an index hospital stay and the results showed that hospitalized frail elderly patients performed below previously described age-related reference values. Furthermore, physical fitness was associated with the degree of frailty, rather than the chronological age.

Paper 2 was a prospective controlled trial, with two parallel groups. The patients included in the intervention group (n=206) were cared for at an emergency medical care unit providing care according to Comprehensive Geriatric Assessment and care (CGA). The control group (n=202) was cared for at conventional emergency medical care units. The multi-professional care approach at the CGA unit was shown to be beneficial, in terms of a greater proportion of patients who preserved or improved their function during the first three months after discharge from hospital, compared with conventional care.

Paper 3 had a prospective approach when evaluating the association between physical fitness and oneyear mortality in those 390 patients discharged alive from a hospital care episode. The results showed that physical fitness during in-hospital care and the change in physical fitness during the first months after discharge were associated with one-year mortality.

In Paper 4, the patients’ perspective in terms of physical activity and exercise was explored. The theme of “Meaningfulness and risk of harm in an aging body” emerged, followed by the three categories of physical activity as part of daily life, goals of physical activity and exercise and prerequisites for physical activity and exercise.

These studies highlight the importance of a greater focus on physical fitness in hospitalized elderly patients. A careful assessment and a multi-professional approach may lead to beneficial results and better survival even in a group of frail elderly patients with severe multimorbidity. To increase physical activity and exercise in this group of patients, health care probably needs to improve the means of communicating the benefits and goals of exercise and facilitating them so that the risk of harm is reduced.