TY - JOUR
T1 - Effect of diurnal temperature range on cardiovascular markers in the elderly in Seoul, Korea
AU - Lim, Youn-Hee
AU - Kim, Ho
AU - Kim, Jin Hee
AU - Bae, Sanghyuk
AU - Hong, Yun-Chul
PY - 2013/7
Y1 - 2013/7
N2 - While diurnal temperature range (DTR) has been found to be a risk factor for mortality, evaluation of the underlying mechanisms involved in this association are lacking. To explain the association between DTR and health effects, we investigated how cardiovascular markers responded to DTR. Data was obtained from 560 participants who regularly attended a community elderly welfare center located in Seoul, Korea. Data collection was conducted a total of five times over a 3-year period beginning in August, 2008. We examined systolic and diastolic blood pressure (BP), heart rate (HR), and heart rate variability (HRV). Mixed-effects models and generalized additive mixed models were used to assess the relationship of DTR with BP, HR, and HRV. BP was not associated significantly with rapid temperature changes during the day. While HR was associated linearly with increments of DTR, the relationship between DTR and HRV showed nonlinear associations, or the presence of a cutoff around median DTR. At the cutoff level of DTR determined by an inflection point in the graph, standard deviation of normal-to-normal intervals (SDNN) and root mean square successive difference (RMSSD) were peaked, whereas the low frequency:high frequency (LF:HF) ratio was elevated with decreasing DTR below the cutoff level. The study demonstrated that HR increases with increasing temperature range during the day, and that HRV is reduced at small or large DTR, which suggests minimal cardiovascular stress around the median level of temperature range during the day.
AB - While diurnal temperature range (DTR) has been found to be a risk factor for mortality, evaluation of the underlying mechanisms involved in this association are lacking. To explain the association between DTR and health effects, we investigated how cardiovascular markers responded to DTR. Data was obtained from 560 participants who regularly attended a community elderly welfare center located in Seoul, Korea. Data collection was conducted a total of five times over a 3-year period beginning in August, 2008. We examined systolic and diastolic blood pressure (BP), heart rate (HR), and heart rate variability (HRV). Mixed-effects models and generalized additive mixed models were used to assess the relationship of DTR with BP, HR, and HRV. BP was not associated significantly with rapid temperature changes during the day. While HR was associated linearly with increments of DTR, the relationship between DTR and HRV showed nonlinear associations, or the presence of a cutoff around median DTR. At the cutoff level of DTR determined by an inflection point in the graph, standard deviation of normal-to-normal intervals (SDNN) and root mean square successive difference (RMSSD) were peaked, whereas the low frequency:high frequency (LF:HF) ratio was elevated with decreasing DTR below the cutoff level. The study demonstrated that HR increases with increasing temperature range during the day, and that HRV is reduced at small or large DTR, which suggests minimal cardiovascular stress around the median level of temperature range during the day.
KW - Aged
KW - Aging/physiology
KW - Blood Pressure
KW - Circadian Rhythm/physiology
KW - Female
KW - Heart Rate
KW - Humans
KW - Male
KW - Republic of Korea
KW - Temperature
U2 - 10.1007/s00484-012-0587-x
DO - 10.1007/s00484-012-0587-x
M3 - Journal article
C2 - 22956153
SN - 0020-7128
VL - 57
SP - 597
EP - 603
JO - International Journal of Biometeorology
JF - International Journal of Biometeorology
IS - 4
ER -