Ever worked in an office where your freezing cold? Where everyone is cold? Where everyone is cold apart from one woman who insists that it’s boiling. And this woman often has some power, quite a bit of sway — she’s older and has been working there the longest. You can’t change the thermostat. No one can — because she’s hot and she has authority over setting the office temperature.In such an environment you usually resort to wearing extra clothes — having a sweater at work, a shawl or even a jacket. This is the only way you can survive in the veritable refrigerator — thanks to the menopausal woman.Hot flashes are the most common symptom for women in menopause and for those in the pre-menopause stage. It’s a sudden feeling of intense heat in the upper body. It can be in the face, neck, face & neck or the whole upper body.While many older women experience or have experienced them, few know exactly what is happening in the body physiologically when a hot flash occurs.The North American Menopause Society speculates that changes in the hypothalamus, the part of the brain that regulates temperature, actually cause hot flashes. The Mayo Clinic sites the same reasoning.The hypothalamus is a neuroendocrine gland at the base of the brain just above the brainstem. It is believed that the hormone oestrogen is one of its chemical messengers that report on body temperature. Because there is a reduction of oestrogen in pre menopause and menopause, the messages to the hypothalamus are disrupted.If the hypothalamus gets a signal that the body is too warm, blood vessels near the skin’s surface dilate to increase blood flow and help dissipate heat. This sudden increase of blood flow causes the skin to become flushed and for the person to suddenly feel hot.Environmental factors can also trigger a hot flash. Alcohol, nicotine, caffeine, spicy foods, exercise, fat and chocolate can all bring one on. Climate — such as a hot room, medication, lack of sleep and stress — may also play a role. If you’re experiencing hot flashes, it makes sense to keep a diary to track some of these environmental conditions that may be triggering them.Although widely believed to be an experience exclusively for women, many men also experience hot flashes. In their cases it is related to a drop in testosterone levels. This may be a natural occurrence due to age or surgical removal of the testes — the place where testosterone is produced.A drop in testosterone levels may also factor into who some women experience hot flashes and the combination of low oestrogen and low testosterone may account for the intensity of the attack. Hot flashes may last a few seconds or several minutes and may manifest in a range from warm — to fire hot.Night sweats happen by the same mechanism. They are essentially hot flashes that happen when you are sleeping.