By the year 2030, in the United States alone, the number of people aged 65 years and older will reach 70 million, with those over 85 constituting the fastest growing segment of all. The promotion of physical activity as a way to treat and prevent disease has therefore become increasingly more important for these older adults. A recurring concept in this thematic issue is that there are very few contraindications to exercise in the elderly. Thus, exercise is medicine and should be enthusiastically-although carefully-prescribed, in one form or another, for almost all of our patients. It is a critical part of the treatment regimen for chronic conditions such as coronary artery disease and osteoarthritis, as well as for common illnesses like depression. Furthermore, the effects of regular physical activity, such as improvements in a person's functional capacity and quality of life, contribute enormously to a healthier, independent lifestyle. In the current reviews, we have tried to capture the issues most relevant to physicians and other health care providers who deal with older athletes. We hope that increased awareness of their unique needs will promote improved care as well as further research in this special-and growing-population.
The primary changes in the cardiovascular system associated with aging are a decrease in elasticity coupled with an increase in stiffness of the arterial system. This alteration in vessel compliance results in increased afterload on the left ventricle, an increase in systolic blood pressure, and left ventricular hypertrophy, as well as other changes in the left ventricular wall that prolong diastolic relaxation. These changes set the stage for isolated systolic hypertension, diastolic dysfunction, atrioventricular conduction defects, and aortic valve calcification-all of which are seen with ever greater frequency in the elderly. Heckman and McKelvie note that many of the age-associated changes in cardiovascular function are not entirely due to aging per se, but rather to a lack of exercise. They go on to provide specific evidence-based strategies that incorporate both aerobic and strength training to optimize cardiovascular function in the healthy elderly.
An area of increasing importance in the older athlete is the impact of exercise on cognition and emotional well-being. van Uffelen and colleagues systematically review the evidence that involvement in regular exercise has a number of psychological benefits, including the preservation of cognitive function, the alleviation of depression, and an improvement in aspects of personal control and self-efficacy among subjects both with and without cognitive decline.
As pointed out by Faulkner and colleagues, a number of physiologic changes occur in skeletal muscle, starting around age 50 years, that may impact athletic performance. These are not completely age-related, however, and losses are strikingly diminished through strength training. The authors provide specific recommendations to limit age-related sarcopenia and strength losses. The use of such approaches will no doubt present challenges to anyone who is privileged to provide counsel and care to competitive athletes of all ages. In addition, the Faulkner paper seeks to raise our awareness to two genes, IGF-1 and myostatin, as potential targets to increase muscle mass.
A question faced everyday by anyone caring for the older athlete is the role of regular exercise in incident and progressive osteoarthritis (OA) Hart and colleagues critically review the EMBASE and MEDLINE databases to shed some light on the fascinating, although controversial, literature on this topic. In the second part of their review they switch constructs-to discuss the application of exercise in the management of older patients with already established OA. The authors end with their suggestions for future studies, including an exploration of possible strategies for exercise in the primary prevention of OA, and the standardization of protocols used in the management of this very common condition, once it has been already diagnosed.
Joint replacement is an inevitable outcome of OA for many patients. In their review, Petrella and Chudyk address this issue and also describe training effects on muscle and tendon structure and function in older adults. Surprisingly, no studies have, to date, focused on the effect of training on older adults who have already had joint replacements. Clearly this is an area in need of investigation: methodologically robust studies are needed to better guide us in exercise prescriptions for older athletes after they have had their arthroplasties.
A frequently asked question by our patients is “What are the effects of exercise on the immune system?” Haaland and colleagues address this topic and note that none of the available data provide clear evidence of the acute or chronic effects of exercise on lymphocyte or natural killer cell numbers or phenotype/activity, with the following exceptions: 1) strength or endurance exercise may cause an acute transient elevation in circulating CD8+ T cells, and 2) regular aerobic exercise appears to enhance immunological memory in the context of vaccination. It is also well known that regular aerobic exercise is associated with a reduction in chronic inflammation. This observation may be the basis for many of the positive effects of exercise in chronic disease management, which appears to be similar for the elderly. Although none of the available studies has clearly documented the clinically relevant immunologic benefits of regular exercise in a controlled clinical trial setting, their negative conclusions may be a function more of under powering of the respective studies rather than a genuine finding.
No discussion of physical activity and its effects on human health and performance in the older athlete would be complete without acknowledgement of the importance of diet and nutrition. Tarnopolsky reviews the protein requirements for resistance exercise training in older adults and provides specific practical recommendations to meet these requirements. He goes on to discuss the evidence underlying vitamin and creatine supplementation. The best available data suggest that older endurance athletes should achieve a daily carbohydrate intake of at least 6 g/kg. For those wishing to “carbohydrate load” prior to an endurance event such as a marathon, an intake of 8 g/kg carbohydrate/d for 3 to 4 days, with reduced training, should lead to similar benefits to those seen in younger adults.
We hope you enjoy this thematic issue dedicated to the older athlete. With an aging active population, we will likely find ourselves confronted more and more by important and challenging questions regarding exercise and physical activity and optimal health. As always, we look forward to your feedback.
Thomas M. Best, MD, PhD
The Ohio State University Sports Medicine Center
Lawrence Hart, MBBCh, MSc