著者

Tadayoshi Miyamoto

出版者

The Japanese Society of Physical Fitness and Sports Medicine

雑誌

The Journal of Physical Fitness and Sports Medicine (ISSN:21868131)

巻号頁・発行日

vol.5, no.5, pp.329-337, 2016-11-25 (Released:2016-11-10)

参考文献数

18

被引用文献数

2 2

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The respiratory control system is an important chemoreflex-feedback control system that maintains arterial partial pressures of CO2 (PaCO2), O2 and pH remarkably constant via ventilatory regulation. It can be divided into two subsystems: a controller (controlling element) and a plant (controlled element). The respiratory operating point (ventilatory or PaCO2 response) is determined by the interplay between the controller (arterial PCO2 [PaCO2] → minute ventilation [VE] relation) and plant (VE → PaCO2 relation) subsystem elements within the respiratory control system. This review outlines the methodology of converting the closed loop of the respiratory control system to an open loop state, then simplifying the controller and plant subsystems, and identifying the input−output relationship using a systems physiological technique (equilibrium diagram method). Changes in central hemodynamics, exercise stimulus, and regular exercise training modify VE and/or PaCO2 levels at rest and during exercise. These respiratory changes can be quantitatively explained by changes in two subsystem elements on the respiratory equilibrium diagram. Using this analysis technique that allows an integrated and quantitative description of the whole respiratory control system will greatly advance the elucidation of pathological conditions manifesting breathing disorders and respiratory regulation during exercise. By repeating thought experiments utilizing this kind of mathematic model and physiological experiments that provide evidence, deeper understanding will be achieved concerning prediction of the behavior of biological systems beyond the physiological range and understanding of the pathophysiology of diseases that are difficult to study by clinical research.

著者

Go Ito Shingo Otsuki Ai Shimada Hideomi Nakata Hidehiro Nakahara Toru Sawai Tadayoshi Miyamoto

出版者

Japanese Society for Medical and Biological Engineering

雑誌

生体医工学 (ISSN:1347443X)

巻号頁・発行日

vol.Annual60, no.Proc, pp.318-321, 2022 (Released:2023-05-12)

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Abstract: In our previous study, low-frequency, short-duration high-intensity interval training (HIIT) was performed for 8-12 weeks in untrained healthy subjects (Once a week, 3 sets, less than 10 minutes total training time), and the results showed that regardless of training intensity, maximal oxygen uptake (VO2max) and exhaustion time during maximal exercise increased by 6-13% and 33-89%. However, it is not clear whether similar results can be obtained in athletes who perform strenuous exercise on a daily basis. The purpose of this study was to investigate the effects of HIIT at different intensities on cardiorespiratory function and exercise performance during maximal exercise in college athletes. The subjects were 13 male college student athletes. The training was determined for each individual using a ramp exercise test to determine the maximum load, divided into 80% (TG80%) or 90% (TG90%) intensity training groups. and conducted once a week for 8 weeks. The training consisted of three bouts of exercises to volitional fatigue at TG80% and TG90% maximum work rate. Regardless different of training intensity, increased VO2max (TG80%: +11%, TG90%: +12%) and maximal work rate during the ramp exercise test (TG80%: +13%, TG90%: +16%) in both groups were observed after HIIT (P <0.01). Maximal exhaustion time during the HIIT (TG80%: +110%, TG90%: +95%) was also significantly prolonged in both groups after training (P < 0.05). In conclusion, low-frequency for short-duration once a week HIIT improves cardiorespiratory function and exercise performance during maximal exercise for athletes, regardless of its training intensity. These findings will contribute to the development of new and optimal exercise programs for various age groups and people, even competitive athletes.