Mental activity during stress

Each sensor has its own limitations that prevent it from accurately simulating metabolic needs during all conditions of exertion and sympathetic stimulation. Activity sensors do not respond to mental stress, anxiety, or fever, which are all potent causes of sinus tachycardia in normal individuals. In addition, some forms of exertion, such as cycling, may not be adequately sensed by activity sensors. In addition, sensors such as minute ventilation may not react as rapidly as some activity sensors to changes in activity. 

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