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.
Some of the signals which trigger the release of hormones include: Hormones from other endocrine glands - Most hormones are released as a result of another hormone being released. For example, thyrotropin releasing hormone (TRH) triggers the release of thyroid stimulating hormone (TSH), which, in turn, triggers the release of thyroxine from the thyroid gland. Blood composition - For example, insulin is released by the pancreatic beta cells in response to a rise in blood sugar after a meal.