As the intensity of exercise becomes higher, increases in the oxygen uptake (VO2) and cardiac output (Q) start to level off, and they will enter a steady state. However, the pulmonary ventilation (VE) continues to increase in an exponential manner even after the VO2 and Q level-off. After exercising to extreme fatigue, the oxygen used by the respiratory muscles (VO2) increases to 10 to 16% of the VO2max. In this situation, the respiratory muscles use the oxygen that would have been allocated to the active muscles because the oxygen used for the entire body is already in a steady state. Therefore, overexercising must be discontinued due to a shortage of oxygen for the active muscles (in the legs); amount of O2 debt has reached its limit. Since the total amount of oxygen that can be taken into the body remains constant, the enhancement of the respiratory muscles and their functions (including the respiratory efficiency (VE/VO2)) in advance is expected to improve their endurance. Several previous studies suggested that respiratory muscle training (RMT) enhances the endurance of subjects. Furthermore, recent studies suggested that RMT not only enhances endurance, but also improves the physical elements of significantly intense exercise (including speed, muscle strength, and power) performed for a short period of time. It is necessary to conduct further research to clarify the mechanism of RMT in the improvement of physical performance. RMT is not expected to improve the VO2max, and the following are possible causes of the improvement of performance: improvements in the respiratory muscles and efficiency (VE/VO2), a subsequent decrease in the blood lactate concentration, and subjective respiratory distress and sense of fatigue in the active muscles.
Cutaneous vasodilator function plays a role in the thermoregulatory system during rest and exercise, and its dysfunction, especially in elderly people, can influence the system’s vulnerability in heat-stressed conditions. In this review, firstly, we describe the mechanisms that control the cutaneous vasculature in humans. The reflex mechanisms by which sympathetic nerves mediate vasoconstriction and active vasodilation during whole-body thermal stress are examined, including discussions of the mechanisms involving cotransmission, nitric oxide (NO) and other mediators. The mechanisms that effect local cutaneous vasomotor responses to local skin warming are also examined, including the roles of axon reflexes as well as NO and other mediators. Next, we highlight the effects of aerobic exercise training on reflexes and local vasomotor control in the skin. Factors that modulate control mechanisms of the cutaneous vasculature, such as aging and clinical conditions, are discussed. Finally, the beneficial influences of exercise training on cutaneous vasodilator function in healthy young and elderly people with or without chronic diseases are emphasized.
Sarcopenia, the decline of muscle mass and function with age, is associated with disability, lifestyle-related diseases, and mortality. Also, it is well known that excess adiposity is associated with increased risk for all-cause mortality. Thus, the co-existence of sarcopenia and abdominal obesity, i.e. sarcopenic obesity, may show a synergistically accumulated risk of mortality. However, to our knowledge results of previous studies have been mixed, and it’s not clear whether sarcopenic obesity is significantly associated with the all-cause mortality. At present, there is no clinical consensus for the definition of sarcopenic obesity across the globe. The purpose of this review is to highlight recent studies on the relationships between cardiovascular diseases risk factors or all-causes mortality and sarcopenic obesity and to discuss the diagnosis or clinical significance of sarcopenic obesity.
Kurort healthy walking is started to spread across the country as an exercise for health promotion utilizing a rich natural environment in Japan. It is characterized by walking on sloping terrain with mild body cooling (a decrease of approximately 2°C in skin temperature). The body cooling induces physiological and biochemical changes such as the decrease in heart rate and increase in energy metabolism. Although the characteristics of kurort healthy walking are a decrease of approximately 2°C in skin temperature, to our knowledge, no study has focused on its effects on the heart rate or metabolism during exercise. This review focuses on mild body cooling and summarises the effects of kurort healthy walking on physiological and biochemical parameters.
Most people who go to fitness clubs or sports gyms for weight control, and many co-medicals and physicians believe that an increase in muscle mass and/or basal metabolic rate (BMR) is possible through a combination of regular exercise and optimal protein intake during weight loss. This seems a myth, and the reasons are discussed in this article. First, muscle mass is quite difficult to quantify. The limitations of body composition measurement should be well understood. Second, increasing muscle mass during weight loss is difficult. This might be attained through strict implementation of a protein-rich, low-carbohydrate diet; high-intensity resistance training; and aerobic exercise for a long duration. However, such a strict regimen is not feasible for most people. Finally, a 1-kg increase in muscle mass corresponds to an increase of only 13 kcal of BMR per day. Thus, an increase in muscle mass of 1 kg is difficult to achieve, while the gained BMR is approximately equivalent to a decrease of 13.5 kcal of BMR according to a 3-kg decrease of adipose tissue. Weight loss, unless through an extremely sophisticated weight control program, contributes to a decrease in BMR. However, it is an accomplished fact that women with significantly less muscle mass and lower BMR live longer than men with more muscle mass and higher BMR, regardless of ethnicity. Maintaining activities of daily living and daily activity function might be more essential.
April 03, 2017 There had been a system trouble from April 1, 2017, 13:24 to April 2, 2017, 16:07(JST) (April 1, 2017, 04:24 to April 2, 2017, 07:07(UTC)) .The service has been back to normal.We apologize for any inconvenience this may cause you.
May 18, 2016 We have released “J-STAGE BETA site”.
May 01, 2015 Please note the "spoofing mail" that pretends to be J-STAGE.