Core concept of integrative medicine: physical activity

Integrative medicine combines alternative medicine with conventional medicine, including acupuncture, hypnotherapy, massage therapy, physical activity, nutrition, stress management, and other nondrug modalities, to prevent and treat chronic diseases. Among these, physical activity (e.g., exercise) is the core concept of integrative medicine to protect our health and fight diseases in the modern era.¹

Physical inactivity (lack of exercise) is a major cause of most chronic diseases and detrimental to health and wellness.² By contrast, physical activity provides health benefits at a low cost, is a readily available therapy, and is relatively free of adverse effects. Physical activity provides us with a challenge to whole-body homeostasis for human development and health. Multiple human organ systems are influenced by physical activity, provoking diverse homeostatic responses to exercise. For example, physical activity helps maintain cerebral blow flow and oxygen supply in the cardiovascular system, stimulate the growth of skeletal muscle mass during development and aging, promote metabolic and hormone systems, and protect against chronic diseases including obesity, diabetes, aging, cardiovascular disease, neurological disease, osteoporosis, and cancer.³

Fortunately, the application of advanced biological techniques and methodological breakthroughs to physical activity helps us better understand the cellular and molecular pathways associated with acute responses and chronic adaptations to physical activity.3, 4, 5 With this concept in mind, this special issue addresses the role of physical activity in health and disease as a core concept in integrative medicine, and provides us with perspectives on the importance of physical activity in numerous homeostatic processes at cell, tissue, and organ levels.

The present special issue of Integrative Medicine Research provides us with interesting reviews and intriguing original papers contributed by excellent scientists in the various fields of physical activity and medicine, suggesting that physical activity is the real core concept of integrative medicine for health and wellness.

Aging is characterized by a progressive loss of skeletal muscle mass (i.e., muscle quantity) and a gradual decline in muscle force and function (i.e., muscle quality) called “sarcopenia.” A selective loss of Type II (fast twitch) muscle fibers during the aging process is associated with age-related decline in strength and performance. Choi (pp. 171–175) reviews age-related functional changes in skeletal muscle and age-related susceptibility to eccentric contraction-induced muscle damage, suggesting that eccentric contraction-induced muscle injury can aggravate sarcopenia. By contrast, Lim (pp. 176–181) summarizes current literatures to assess the therapeutic potential of eccentric exercises for age-related sarcopenia. He emphasizes that exercise interventions for older adults should focus on enhancing the muscle force–velocity relationship and that the relative preservation of eccentric strength in aging can be a result of the therapeutic potential of eccentric exercises in older adults. There is accumulating evidence that one of the potential mechanisms of age-induced sarcopenia may be mitochondrial dysfunction in aging skeletal muscle. Seo et al. (pp. 182–186) review previous findings on the relationship between aging process and impairment of mitochondrial function, including mitochondrial biogenesis, oxidative stress, and mitophagy in skeletal muscle, suggesting that mitochondrial dysfunction adversely affects the quantity and quality of skeletal muscle with aging. In addition, they emphasize the role of exercise to protect against age-related changes in skeletal muscle mitochondrial function. Exercise-induced mitochondrial biogenesis in skeletal muscle is regulated by a number of molecular proteins and signaling pathways. Erlich et al. (pp. 187–197) summarize multiple proteins and signaling for mitochondrial biogenesis in skeletal muscle response to exercise, including peroxisome proliferator-activated receptor-γ coactivator 1α, mitochondrial transcription factor A, p53, unfolded protein response, and nuclear factor erythroid 2-related factor 2 associated with the regulation of mitochondrial content and function.

In the modern society, metabolic disorders and cardiovascular diseases are becoming major health problems, and reduced physical activity is associated with obesity, Type 2 diabetes, hypertension, cardiovascular disease, and cancer. In particular, insulin resistance is a metabolic disorder that upregulates the risk of cardiovascular complications. Hwang and Lee (pp. 198–203) introduce a putative potential mechanism for vascular dysfunction and summarize previous findings reporting the effects of exercise training on vascular function in both individuals with insulin resistance and experimental animal models, suggesting that physical activity has beneficial effects on vascular function. Interestingly, Figueroa et al. (pp. 204–211) introduce whole-body vibration as an alternative novel modality to traditional resistance training, showing beneficial effects on vascular function by decreasing systemic and leg arterial stiffness in older adults. In fact, increased arterial stiffness is associated with hypertension and cardiovascular events. Furthermore, a decreased high-density lipoprotein cholesterol level is associated with increased cardiovascular events such as coronary artery disease. Ahn and Kim (pp. 212–215) summarize the role of high-density lipoprotein cholesterol in cardiovascular diseases and obesity, and show the effects of exercise training on high-density lipoprotein cholesterol homeostasis in cardiovascular diseases and metabolic syndrome. Recently, Korean Red Ginseng as a traditional Korean medicine has been shown to have antihypertensive benefits as a potential modulator of vascular function. Nagar et al. (pp. 223–229) investigate the beneficial effects of Rg3-enriched Korean Red Ginseng on blood pressure stability in spontaneously hypertensive rats.

The human body produces or loses heat through thermoregulation to maintain the homeostasis of body temperature and protect itself against excessive heat or cold. Furthermore, environmental temperature may affect physiological responses to exercise through thermoregulation. No and Kwak (pp. 216–222) demonstrate the effects of environmental temperature on physiological responses and endurance exercise capacity, suggesting that exercise in extreme cold or heat exerts heavy stress on body thermoregulation and physical performance. Short communication by Kim et al. (pp. 230–235) raises an intriguing issue on muscle-derived cytokines, fibroblast growth factor 2, which influences muscle growth and regeneration associated with the proliferation of satellite cells. They demonstrate the effect of resistance training on fibroblast growth factor 2 protein levels in mice with aged skeletal muscle, showing that fibroblast growth factor 2 protein levels are significantly reduced in aged skeletal muscle by resistance training.

Taken together, physical activity is essential for the prevention and treatment of modern chronic diseases, suggesting that physical activity is a powerful medicine, the real polypill to improve health and well-being, and a therapeutic modality of chronic diseases.⁶ However, although the beneficial effects of physical activity are well documented in previous and current literatures, the cellular and molecular mechanisms by which physical activity prevents chronic diseases and improves health outcomes are poorly understood, which will be challenges for future research.

Conflicts of interest

The author declares no conflicts of interest.