Alterations of Temperature in the External Auditory Meatus and in the Face during Exercise Preparation

To study the brain temperature rise before powerful exercise, we measured the temperature in the external auditory meatus (EAM) and the facial temperature. Subjects had an exercise in which they pulled the back muscle dynamometer as quickly and powerfully as possible and maintained it at the most powerful position for 10 s. The subjects were instructed to keep their eyes closed during the exercise. Temperature in EAM was measured by IR-camera with an IR-optical fiber. Facial temperature was measured by an IR-camera. Thermal images were recorded every 0.1 s with a real time recorder. EEG at F7 and F8 on the forehead and EMG on the right medial gastrocnemius muscle were recorded simultaneously on a magnetic tape of a data recorder. EAM temperature was calibrated to body temperature using a regression curve calculated by the difference between ambient temperature and an object temperature. Facial temperature was calculated per m2. The recorded EEG signal was analyzed by a FFT program in our laboratory. The power spectrum density (PSD) in the EEG frequency was calculated every 0.1 s. While a subject determined a position of feet and stance for an exercise, EAM temperature and facial temperature of the forehead increased, and surface EMG showed small amplitude activity. Facial temperature of the lower region did not change. When the temperature in EAM and forehead raised just before exercise, PSD in EEG of β-wave increased and PSD of α-wave decreased. The results of EMG and EEG activities show how exercises were prepared. Furthermore, it has been resulted that the temperature change in EAM and forehead were raised at the same time during exercise preparation. It is suggested that these alterations of temperature were related to physiological information during exercise preparation like EEG and EMG.