Even methane (natural gas) is lighter than air, but not by much. Carbon dioxide, which is contained in the air we breathe out and is also easily and safely manufactured by mixing bicarbonate of soda and vinegar, is heavier than air. It tends to sink to the floor and accumulate. So it's a good job that houses aren't air tight.
Cuddling, holding, and sexual play releases chemicals, like oxytocin, in the brain that create a sense of well-being and happiness, says Dr. Renee Horowitz, an ob-gyn who recently opened the Center for Sexual Wellness in Farmington Hills, Michigan.
Both cortisol and adrenaline are released in response to stress. Cortisol production is regulated by the pituitary gland. This is a small gland behind the nose and under the brain. The pituitary gland releases adrenocorticotropic hormone (ACTH). This is a hormone that causes the adrenal glands to release cortisol. Adrenaline production is regulated by nerves coming from the brain and spinal cord and by circulating hormones.