Lose weight: Creating a calorie deficit that results in weight loss is hard work. Most recommendations say that to lose weight, you must exercise for at least an hour a day, five times a week. The type of exercise matters, too.
Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia. hair shaft. the nongrowing portion of a hair that protrudes from the skin, that is, from the follicle. hair shaft. The keratinized portion of a hair that extends from a hair follicle beyond the surface of the epidermis.
The hair shaft - the hair we can see - is actually dead. It's made up of three layers of keratin, a hardening protein. The innermost layer of the hair shaft is the medulla. Depending on the type of hair, the medulla may not always be present. The middle layer is the cortex, which makes up the majority of the hair shaft.