The pulse rate goes up astonishingly. There are records of its reaching 150 and more as the individual approaches and then reaches the sexual climax. Such pulse rates generally occur, in health, only in athletes who are performing prodigious tasks of speed or endurance.
The blood pressure, too, goes up precipitately. In a matter of a few seconds it can rise well over 100 points. Breathing also becomes much deeper and swifter. With the approach of orgasm the breathing becomes interrupted; inspiration comes in forced gasps and expiration occurs with a heavy collapse of the lungs. It is as though the sexually excited person had been in a race.
As the sexual act continues there is a general shortage of oxygen throughout the body, which accounts for the unusual breathing. This gives rise to a tortured expression on the face, as if the person were undergoing severe pain. This fact has been observed by Kinsey in his famous study of female sexuality, and I quote here an interesting paragraph on the phenomenon:
". . . Prostitutes who attempt to deceive (jive) their patrons, or unresponsive wives who similarly attempt to make their husbands believe that they are enjoying coitus, fall into an error because they assume that an erotically aroused person should look happy and pleased and should smile and become increasingly alert as he or she approaches the culmination of the act. On the contrary, an individual who is really responding is as incapable of looking happy as the individual who is being tortured."
Within seconds after sexual arousal the blood supply in the veins and arteries lying close to the skin increases, causing the body to become flushed and the temperature to rise slightly. Certain areas of the body are engorged with this blood, become swollen and erect, notably the penis of the man, which swells, often to twice its size. In women, this also
