An article in today's (December 29, 2020) issue of The Wall Street Journal told of Silicon Valley's recent financing of startups marketing hypnosis apps aroused by stress caused by the pandemic. Yet hypnosis is a long accepted psychological technique for alleviating the distress of many conditions including cancer, burns, high blood pressure, headaches, and childbirth. It is taught to asthmatic children since the less stress they experience the less likely they are to have an asthma attack.
Basically, hypnosis is "selective attention" with researchers having varied between considering it a learned reaction to those believing it a entirely different physiological state. I have long believed the latter based on personal experience, that of feeling a "drop" at some point and being reluctant to "wake-up."
About ninety-percent of the population can use hypnosis to reduce stress, with ten-percent of these being such good subjects that major surgery can be performed while in the hypnotic state. Ten-percent of the population can't be hypnotized. A quick test of hypnotic suggestibility is asking whether the subject lost themselves in reading as a child, they usually being good hypnotic subjects. Using hypnosis to lose weight or stop smoking depends on motivation and rapid change should not be expected. Those who accomplished this were extraordinarily well-motivated.
Several warnngs: (1) do not become a subject for a hypnosis event in a club or while on a cruise ship. While often skillful practitioners, there have been cases in which not all of their suggestions were eliminated with the subject winding up in an Emergency Room weeks later complaining of weird symptoms that no one can figure out; (2) do not use hypnosis while wearing contact lenses; (3) do not use listen to a hypnosis audio while driving (this may seem obvious, but...).
With these cautions, hypnosis is eminently safe though best learned with professional guidance (the American Society of Clinical Hypnosis can be contacted for a local practitioner).
On a personal note, decades ago a nurse who took the blood pressure of clinic workers advised that mine was high. A physician who I had known since my teenage years agreed, saying that if it stayed that way I could take medication, which I was adamant against. Taking my blood pressure frequently would more likely yield accurate readings, he added (having abnormally readings during a stressful doctor's visit is well known).
I followed his advice, also frequently using using a self-hypnotic relaxation audio that I made from the research protocol in a journal article relating the use of hypnosis to stress reduction and the development of cancer. After two months, my blood pressure readings became optimal and have remained so.
By graphing these readings I found that my systolic reading (higher number, the force of blood against the artery walls) correlated with my pulse rate while my diastolic reading (lower number, the heart's resting rate or blood pressure between heartbeats) was independent of both. With digital blood pressure monitors being cheap, it would be well for all to monitor their blood pressure at home.