Divergent effects of laughter and mental stress on arterial stiffness and central hemodynamics.
OBJECTIVE
To investigate the effect of laughter and mental stress on arterial stiffness and central hemodynamics. Arterial stiffness and wave reflections are independent predictors of cardiovascular risk. Chronic psychological stress is an independent risk factor for cardiovascular events, whereas acute stress deteriorates vascular function.


METHODS
Eighteen healthy individuals were studied on three occasions, according to a randomized, single-blind, crossover, sham procedure-controlled design. The effects of viewing a 30-minute segment of two films inducing laughter or stress were assessed. Carotid-femoral pulse wave velocity was used as an index of arterial stiffness; augmentation index was used as a measure of wave reflections.


RESULTS
Laughter decreased pulse wave velocity (by 0.30 m/sec, p = .01), and augmentation index (by 2.72%, p = .05). Conversely, stress increased pulse wave velocity (by 0.29 m/sec, p = .05) and augmentation index (by 5.1%, p = .005). Laughter decreased cortisol levels by 1.67 microg/dl (p = .02), soluble P-selectin by 26 ng/ml (p = .02) and marginally von Willebrand factor (by 2.4%, p = .07) and increased total oxidative status (by 61 micromol/L, p < .001). Stress decreased interleukin-6 (by 0.11 pg/ml, p = .04) and increased total oxidative status (by 44 micromol/L, p = .007). Soluble CD40 ligand and fibrinogen remained unchanged.


CONCLUSIONS
Positive (laughter) and negative (stress) behavioral interventions have divergent acute effects on arterial stiffness and wave reflections. These findings have important clinical implications extending the spectrum of lifestyle modifications that can ameliorate arterial function.
Vlachopoulos
Charalambos
C
Peripheral Vessels Unit, 1st Cardiology Department, Athens Medical School, Hippokration Hospital, Athens, Greece. cvlachop@otenet.gr
Xaplanteris
Panagiotis
P
Alexopoulos
Nikolaos
N
Aznaouridis
Konstantinos
K
Vasiliadou
Carmen
C
Baou
Katerina
K
Stefanadi
Elli
E
Stefanadis
Christodoulos
C
D000328:Adult; D002339:Carotid Arteries / Q000502:physiology; D018592:Cross-Over Studies; D005260:Female; D005263:Femoral Artery / Q000502:physiology; D005342:Fibrinolysis; D006439:Hemodynamics; D006728:Hormones / Q000097:blood; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D018836:Inflammation Mediators / Q000097:blood; D015850:Interleukin-6 / Q000097:blood; D007845:Laughter / Q000502:physiology*; D008297:Male; D018384:Oxidative Stress; D019007:P-Selectin / Q000032:analysis; D016037:Single-Blind Method; D013315:Stress, Psychological / Q000097:blood / Q000503:physiopathology*; D014655:Vascular Resistance; D055815:Young Adult; D014841:von Willebrand Factor / Q000032:analysis
D006728:Hormones; C508600:IL6 protein, human; D018836:Inflammation Mediators; D015850:Interleukin-6; D019007:P-Selectin; D014841:von Willebrand Factor; D006854:Hydrocortisone