Journal of Rehabilitation Medicine 51-8 | Page 71

J Rehabil Med 2019; 51: 607–615 ORIGINAL REPORT RELATIONSHIPS AMONG MEASURES OF PHYSICAL FITNESS IN ADULT PATIENTS WITH HEART FAILURE Oronzo CHIALÀ, PhD, RN 1 , Ercole VELLONE, PhD, RN, FESC 1 , Leonie KLOMPSTRA, PhD 3 , Giorgio Alberto ORTALI, MD 2 , Anna STRÖMBERG, PhD, RN, FESC, FAAN 4 and Tiny JAARSMA, PhD, RN, FESC, FAAN 3 From the 1 Biomedicine and Prevention, University of Rome Tor Vergata, Rome, 2 Cardio-Pulmonary Rehabilitation, Casa di Cura “Villa delle Querce” Nemi, Italy, 3 Department of Nursing, Faculty of Medicine and Health Sciences Linköping University and 4 Department of Medical and Health Sciences, Division of Nursing, and Department of Cardiology, Linköping University, Linköping, Sweden Objectives: To describe the relationships among 3 measures of physical fitness (exercise capacity, muscle function and functional capacity) in patients with heart failure, and to determine whether these measures are influenced by impairment of move- ment. Methods: Secondary analysis of baseline data from the Italian subsample (n  = 96) of patients with heart failure enrolled in a randomized controlled trial, the HF-Wii study. Exercise capacity was measured with the 6-min walk test, muscle function was measured with the unilateral isotonic heel-lift, bilateral isome- tric shoulder abduction and unilateral isotonic shoul- der flexion, and functional capacity was measured with the Duke Activity Status Index. Principal com- ponent analysis was used to detect covariance of the data. Results: Exercise capacity correlated with all of the tests related to muscle function (r  = 0.691–0.423, p  < 0.001) and functional capacity (r  = 0.531). Mo- reover, functional capacity correlated with muscle func ­ tion (r  = 0.482–0.393). Principal component analysis revealed the bidimensional structure of the- se 3 measures, thus accounting for 58% of the total variance in the variables measured. Conclusion: Despite the correlations among exercise capacity, muscle function and functional capacity, these measures loaded on 2 different factors. The use of a wider range of tests will help clinicians to perform a more tailored assessment of physical fit- ness, especially in those patients with heart failure who have impairment of movement. Key words: heart failure; physical fitness; exercise capacity; muscle function; functional capacity; movement impairment; rehabilitation. Accepted May 28, 2019; Epub ahead of print Jun 18, 2019 J Rehabil Med 2019; 51: 607–615 Correspondence address: Prof dr T. Jaarsma, Department of Nursing, Faculty of Medical and Health Sciences, University of Linköping, Norr- köping Sweden. E-mail: [email protected] R educed physical fitness is a common problem in patients with heart failure (HF) (1). Physical fitness is complex and includes several objective and sub- jective domains, of which the most important and the most evaluated are: exercise capacity, muscle function, and functional capacity (2). This multidimensionality LAY ABSTRACT Physical fitness is a complex concept, and is particular- ly affected in patients with heart failure, especially in those with impairment of movement. Physical fitness is often assessed by examining only some of the fac- tors involved, mainly based on physical endurance or strength. This study explored the relationship among 3 different measures of physical fitness: exercise ca- pacity, muscle function and functional capacity. More- over, the study showed how these 3 measures, despite their good correlation, can be used to assess 2 different factors related to physical fitness. These results should encourage clinicians to choose a tailored strategy to as- sess physical fitness in patients with heart failure, pay- ing particular attention to patients with impairment of movement. in physical fitness should be explored using multiple methods, not with tests that evaluate only physical ca- pacity. A proportion of patients with HF may be unable to perform or complete physical tests due to impairment of movement (3, 4), such as chronic shoulder or knee pain reducing their capacity for exercise (5). Exercise capacity was defined as the maximum amount of physical exertion that a person can sustain (6). Lower exercise capacity (e.g. <300 meters in the 6-min walk test (6MWT)) is strongly associated with higher mortality due to HF (7). Higher exercise ca- pacity allows patients with HF to be more active at a greater intensity or for a longer period and to perform activities of daily living better (8). A 5% improvement in exercise capacity is associated with a 10% reduction in cardiac re-hospitalization and all-cause mortality risk (9). In most cases, exercise capacity is measured with the 6MWT. However, this test only measures the distance (in m) walked in 6 min (10), and does not evaluate the exercise capacity of the upper limbs. Muscle function is determined by a combination of muscle mass, muscle strength and muscle power (11). Muscle function is particularly affected in patients with HF, possibly because of a maladaptation in the skeletal muscle fibres (12). Muscle function in patients with HF is important in the rehabilitation setting because it allows for a more comprehensive exploration of phy- sical fitness. This assessment is currently not performed with a single standard method, but through a variety of This is an open access article under the CC BY-NC license. www.medicaljournals.se/jrm Journal Compilation © 2019 Foundation of Rehabilitation Information. ISSN 1650-1977 doi: 10.2340/16501977-2574