Relationship between ventilatory response and body temperature during prolonged submaximal exercise

• Published in: Journal of applied physiology (1985) 2006-02, Vol.100 (2), p.414-420
• Main Authors: Hayashi, Keiji, Honda, Yasushi, Ogawa, Takeshi, Kondo, Narihiko, Nishiyasu, Takeshi
• Format: Article
• Language: English
• Subjects: Adult; Biological and medical sciences; Body Temperature; Body Temperature Regulation - physiology; Esophagus; Exercise; Exercise - physiology; Exercise Test; Fundamental and applied biological sciences. Psychology; Heart Rate; Heat; Hot Temperature; Humans; Hyperventilation - etiology; Male; Pulmonary Ventilation - physiology; Respiratory Mechanics - physiology; Respiratory system; Skin; Skin Temperature; Temperature; Time Factors
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00541.2005

1 Institute of Health and Sports Science, University of Tsukuba, Tsukuba City; and 2 Faculty of Human Development, Kobe University, Kobe, Japan Submitted 9 May 2005 ; accepted in final form 19 September 2005 We examined whether an increase in skin temperature or the rate of increase in core body temperature influences the relationship between minute ventilation ( E ) and core temperature during prolonged exercise in the heat. Thirteen subjects exercised for 60 min on a cycle ergometer at 50% of peak oxygen uptake while wearing a suit perfused with water at 10°C (T10), 35°C (T35), or 45°C (T45). During the exercise, esophageal temperature (T es ), skin temperature, heart rate (HR), E , tidal volume, respiratory frequency (f), respiratory gases, blood pressure (BP), and blood lactate were all measured. We found that oxygen uptake, carbon dioxide output, BP, and blood lactate did not differ among the sessions. T es , HR, E , and f remained nearly constant from minute 10 onward in the T10 session, but all of these parameters progressively increased in the T35 and T45 sessions, and significantly higher levels were seen in the T45 than the T35 session. For all but two subjects in the T35 and T45 sessions, plotting E as a function of T es revealed no threshold for hyperventilation; instead, increases in E were linearly related to T es , and there were no significant differences in the slopes or intercepts between the T35 and T45 sessions. Thus, during prolonged submaximal exercise in the heat, E increases with core temperature, and the influences of skin temperature and the rate of increase in T es on the relationship between E and T es are apparently small. core temperature; skin temperature; ventilation; respiration Address for reprint requests and other correspondence: T. Nishiyasu, Institute of Health and Sports Science, Univ. of Tsukuba, Tsukuba City, Ibaraki 305-8574, Japan (e-mail: nisiyasu{at}taiiku.tsukuba.ac.jp )