WHAT do you call a cat that swallows a duck? A duck-filled-fatty-puss.
Two antennas meet and fall in love. Their wedding was terrible, but the reception was brilliant!
A neutron orders a pint of beer. The barman hands it to him and says, 鈥淔or you, no charge!鈥�
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In the unlikely event that any of these made you laugh, you may have done your blood vessels a favour. Laughing appears to be almost as beneficial as a workout.
鈥淭hirty minutes of exercise three times a week and 15 minutes of hearty laughter each day should be part of a healthy lifestyle,鈥� says Michael Miller of the University of Maryland Medical Center in Baltimore, Maryland, whose team showed that laughter relaxes arteries and boosts blood flow.
Miller made ultrasound measurements of blood flow and dilation in the brachial artery of the upper arm of 20 volunteers before and after showing them clips from the comedy movie Kingpin. In all but one of them, the artery had relaxed and blood flowed more freely than usual for 30 to 45 minutes afterwards.
When the same people watched harrowing scenes from the war movie Saving Private Ryan, the opposite happened. In 14 of the volunteers the artery constricted, reducing blood flow. Overall, blood flow decreased by 35 per cent after the stressful clips and increased by 22 per cent after laughter.
All this suggests that laughter could help keep the lining of the arteries 鈥� the endothelium 鈥� healthy and thus reduce the risk of cardiovascular disease. 鈥淎t the very least, laughter offsets the impact of mental stress, which is harmful to the endothelium,鈥� Miller says.
鈥淚t鈥檚 logical that positive emotions might have the opposite effect to stress,鈥� says Andrew Steptoe of University College London, whose studies in 2000 showed that acute mental stress impairs endothelial function. Miller, who presented his results to the American College of Cardiology meeting in Orlando, Florida, this week, now hopes to find out why laughter is beneficial. 鈥淲e don鈥檛 know if there鈥檚 a direct effect by laughing, or an indirect effect by reducing stress.鈥�
