Sex differences in cardiac sympathovagal balance and vagal tone during nocturnal sleep.
|Title||Sex differences in cardiac sympathovagal balance and vagal tone during nocturnal sleep.|
|Publication Type||Journal Article|
|Year of Publication||2008|
|Authors||Valladares EM, Eljammal SM, Motivala S, Ehlers CL, Irwin MR|
|Date Published||2008 Mar|
|Keywords||Adult, Electrocardiography, Female, Heart, Heart Rate, Humans, Male, Middle Aged, Polysomnography, Reference Values, Sex Factors, Sleep, Sympathetic Nervous System, Vagus Nerve|
OBJECTIVE: To analyze sex differences in nocturnal vagal tone and cardiac sympathovagal balance during sleep in healthy men and women.
METHODS: In two groups of healthy, non-obese adults (15 men and 14 women), sleep was polygraphically recorded and heart rate variability was assessed during an awake period prior to sleep and during sleep. Vagal tone was estimated by the high-frequency (HF) power component of heart rate variability, and sympathovagal balance was indexed by the ratio of low-frequency (LF) power to HF power.
RESULTS: As compared to women, men showed decreases in vagal tone and increases in sympathovagal balance. During rapid eye movement (REM) sleep, a withdrawal of vagal tone occurred with an increase in sympathetic dominance. Men showed a greater increase of sympathovagal balance during REM sleep than women. Secondary analyses covarying for differences in reproductive hormone levels, physical activity, and sleep measures did not alter the results.
CONCLUSIONS: The marked increase in cardiac sympathetic drive during REM sleep in men has implications for understanding sex differences in the risk of cardiovascular events. Additionally, these data offer a pathway to explain the peak in cardiac arrhythmias and sudden cardiac death seen more often in the morning hours.
|Alternate Journal||Sleep Med.|
|Grant List||AA13239 / AA / NIAAA NIH HHS / United States |
AG026364 / AG / NIA NIH HHS / United States
DA16541 / DA / NIDA NIH HHS / United States
HL079955 / HL / NHLBI NIH HHS / United States
M01 RR000865 / RR / NCRR NIH HHS / United States
M01-RR00865 / RR / NCRR NIH HHS / United States
R01 AA013239 / AA / NIAAA NIH HHS / United States
R01 DA016541 / DA / NIDA NIH HHS / United States
R01 HL079955 / HL / NHLBI NIH HHS / United States
T32 MH019925 / MH / NIMH NIH HHS / United States
T32-MH19925 / MH / NIMH NIH HHS / United States