What a hot flash really is
While the mechanism of this is not fully understood, it looks as though a hot flash results from a delusion on the part of the hypothalamus (a portion of the brain that is the master conductor for a number of hormone interactions) that your core body temperature has just zoomed up. In panic, the hypothalamus releases a flood of the neurotransmitter norepinephrine into the system to cause sweating and peripheral dilation of the blood vessels (which is why your face flushes). These tactics are intended to dump body heat by radiation and evaporation. They also result in a massive increase in the amount of fatty acids in the blood.
Meanwhile, your pituitary gland has kept its wits about it and refuses to go along with the panic. It lets loose with a blast of ACTH (another hormone) to send the message to the hypothalamus that it's time to chill out—which the body obligingly does. The hot flash is over and, because you didn't really need to drop your temperature, you are now chilled.
But wait—there's more! The ACTH blast calls up your basic stress hormone, cortisol, which then signals your body to store all that circulating fat instead of burning it. And there you have it: not only hot, sweaty, chilled, embarrassed, but on your way to being a little fatter besides. This, as one of our dear friends puts it, vacuums.
Hot flashes and hormone balancing
Unfortunately, because hot flashes are a part of the profile of hormone fluctuations, they are an inescapable part of hormone balancing. This is aggravating, but, without being too Pollyanna about things, can also be helpful.
Women under the misapprehension that flashes mean low estrogen will often want to adjust their estrogen upwards so long as they are having flashes. But once they know that it is any change that causes flashes, not just a low level, they tend not to be as confused and raise their doses to excess when in fact that may make things worse yet.
Furthermore, once we understand that change = flash, we can be cheered up by the onset of flashes following an HRT adjustment: we now know by the flash that our body is in fact seeing and responding to changed circulating hormone levels. What we're doing worked insofar as our body is seeing the change! Even more, when our flashes taper off, we can take this as a signal that we are settling in.
Additionally, flashes can alert us that, in the absence of HRT adjustments, something else may have changed—perhaps the addition of a lifestyle, chemical or dietary change—that is affecting our hormone levels. So, wretched as they are, hot flashes do serve a useful purpose.
Coping with hot flashes
While we are putting up with the flashes, there are a few things we can do to lessen their impact.
One of the obvious things is to lower your body temperature as much as you can on your own when you feel a flash begin (many women can tell just a few seconds before they are going to have a flash, even when they can't explicitly describe how they do it). The classic measures are to dress in layers, so that you can rapidly add and subtract, and enhance ventilation and air movement around you. This can vary from carrying a fan (manual or battery-operated) to opening windows to changing settings on air conditioners and heaters to running outside to cooler conditions. A newer generation of cooling clothing made for sports, like evaporative bandanas and vests, or chillable pillows for sleeping, may also help by mechanically providing local cooling on the necessary intermittent basis.
Night sweats are particularly difficult because you may not awaken in time to prevent soaking through nightclothes and covers, leaving you the option of getting up to change your bed or shiver in wet linens. Some of us have found that sleeping without a gown and buying two single duvets (for a double bed) allows us to rapidly cool off without disturbing a spouse as much. Another useful tactic for avoiding marital discord is to buy hubby a single electric blanket to make up for your wanting to sleep with windows open or the A/C turned up to max. But night sweats carry a double whammy, in that in addition to the aggravation of the flash/sweat itself, you are also going to suffer from interrupted sleep. For women who undergo lengthy periods of frequent flashes, sleep deprivation can be a real and serious problem.
Other measures that have been cited as useful for some include deep breathing during a flash or quickly downing a full glass of ice water as soon as it starts (to chill core temperature). Larrian Gillespie, author of The Menopause Diet, has suggested that 500 mg/day of the amino acid L-arginine may be effective. Other sources suggest that Vitamin E can help lower the incidence and severity of flashes. A class of antidepressants, the SSRIs, have been shown to reduce hot flash frequency and intensity, but because of their relatively lengthy period of onset (several weeks to months) and more significant impact, they are more appropriate as a long term strategy for those who cannot take HRT than for relief of short term flashes due to HRT adjustments. Estrogenic supplements (such as black cohosh or red clover) will obviously impact flashes; whole soy has also been demonstrated to help in some cases, but overall, that's just going to add more estrogen fluctuation to the mix and thus be unsuitable for short term, as opposed to long term, flashes.
The bottom line is that there are lots of things that may help with flashes, but you will probably need to experiment to find the ones that work the best for you.
And keep in mind that it's not necessary to eliminate all flashes. Some women, especially those who are trying to minimize their hormone exposure and shave the very bottom edge of hormone adequacy, rely on having just a few mild flashes as a gauge of just where they are relative to that line. Women who are otherwise meeting their hormone needs may decide that going on to try to eliminate hot flashes altogether is more fuss than they want to go through and just put with them. Women who have no other hormone needs or have identified no other menopausal health needs they care to address may decide that hot flashes are something they can tolerate. It all comes back to how you define your own goals and needs.