Hot flashes, core body temperature, and metabolic parameters in breast cancer survivors

To examine core body temperature, energy expenditure, and respiratory quotient among breast cancer survivors experiencing hot flashes and compare these data to published studies from healthy women.

In an observational study, nine breast cancer survivors with daily hot flashes who met specified criteria spent 24 hours in a temperature- and humidity-controlled whole-room indirect calorimeter (ie, metabolic room). Demographic and disease/treatment information were obtained and the following were measured: hot flashes via sternal skin conductance monitoring (sampled every second); core body temperature via an ingested radiotelemetry pill (sampled every 10 seconds); and energy expenditure and respiratory quotient via a whole-room indirect calorimeter (calculated every minute).

Circadian analysis of core temperature indicated wide variability with disrupted circadian rhythm noted in all women. Core temperature began to rise 20 minutes pre-flash to 7 minutes pre-flash (0.09 degrees C increase). Increases in energy expenditure and respiratory quotient increased with each hot flash.

Findings are comparable to published data from healthy women and warrant replication in larger, more diverse samples of women treated for breast cancer.