monitoring durations (weeks or more). However, researchers should be aware that
daily diaries are still vulnerable to error due to compliance issues, mood, and
physical state of the participant at the time of completion as well as the influence of
recall and reconstruction.
Hot Flash Reports at Time of Event
Another method to assess hotflashes is to have women report their hotflashes at the
time of their occurrence, typically via electronic diaries, paper diaries, or with event
markers. These instruments have the major advantage of increased data precision
and accuracy, while avoiding the problems of distortion and biases associated with
recall. Electronic diaries and event markers provide precise electronic date and
time-stamped records for subjective hotflash occurrence (Stone et al. 2003 ).
However, participant compliance remains a concern, as women need to stop their
activities to report their hotflashes, and non-adherence to hotflash reporting can
masquerade as the absence of hotflashes or response to a treatment. For that reason,
methods requiring minimal intrusion (e.g., button press on a monitor) are recom-
mended over more extensive electronic diary entries, and monitoring periods of
relatively short durations (e.g., several days) may yield more precise hotflash
estimates than more lengthy periods (although this issue has yet to be studied). In
sum, event markers of hotflashes may provide more precise estimates of hotflash
frequency, intensity, and bother, but may also involve higher participant burden
than questionnaires and end-of-the-day diaries. Hotflash dairies completed at the
time of the hotflash may provide the most precise estimates for subjective hot
flashes if using electronic methods to ensure adherence.
Physiologic Measures
Though physiologic changes during hotflashes were described as early as the 1940s
(Reynolds 1941 ; Collett 1949 ), detailed investigations of hotflash physiology did
not begin until the 1970s when Molnar revealed changes in heart rate, sweating,
skin, and core temperature during hotflashes (Molnar 1975 ). Subsequent studies
corroborated and expanded these results, showing that hotflashes have concomitant
changes in skin temperature (Freedman 1998 ; Tataryn et al. 1980 ; Kronenberg et al.
1984 ), sweat gland activity (Molnar 1975 ; Freedman 1998 ), heart rate (Kronenberg
1990 ; Kronenberg et al. 1984 ), bloodflow (Tataryn et al. 1980 ; Ginsburg et al.
1981 ), and respiratory exchange ratio (an estimate of metabolic rate; Woodward
et al. 1995 ; Freedman 1998 ). Early investigations into a physiologic indicator of hot
flashes suggested that sternal skin conductance was an effective measure of hot
flashes (Tataryn et al. 1981 ).
238 W.I. Fisher and R.C. Thurston