Previous work on passive heating suggests impaired thermoregulatory responses in heart failure patients.  However, no previous study directly examined thermoregulatory responses to an exercise bout, that is, active heating, as typically applied in rehabilitation settings in heart failure.


 Tcore (telemetric temperature pill) and Tskin (skin thermistors) were measured continuously during a 45-min cycle exercise at comparable relative exercise intensity.


 Furthermore, we found that a given change in Tcore was associated with a smaller increase in Tskin in heart failure patients compared with controls.  These impaired thermoregulatory responses to exercise are, at least partly, explained by the lower absolute workload and lower physical fitness level in heart failure patients.
THERM