Figure 3

Core temperatures in a typical normal subject and typical patient, measured in the pulmonary artery (Tpa). From data of Shellock, et al (17) in a study of class III and IV heart failure patients and age-matched normal subjects. Rectangle indicates period in which subjects exercised on a bicycle ergometer in successive three-minute periods at work loads of zero, 25W and 50W. Heart failure patients had lower Tpa prior to exercise (36.95 versus 37.28° C) and still lower Tpa at the end of the exercise period (10 min post-exercise Tpa 36.87 in patients versus 37.43 in normal subjects). Also, deep muscle temperature from the vastus lateralis was lower in patients before exercise (34.8 versus 36.2° C) and did not rise above Tpa during exercise (muscle temperature at completion of 50W exercise 36.5 in patients versus 38.0° C in normal subjects).