Studies have found that cold weather increases the rate of heart attacks as well as strokes, especially in older people with cardiovascular disease. Cold temperatures can increase blood pressure and the tendency of blood to clot as well as stimulate production of stress hormones. In particular, sudden drops in temperature or barometric pressure (as before the onset of a storm) appear to increase the risk. Frigid damp weather is generally riskier in regions where people are not used to cold weather than in places like Canada or Siberia. Dressing warmly may actually help save the lives of people at high risk for heart attack.
Adequate indoor humidity (25 to 50 percent) can help prevent or alleviate dry skin, eyes and nasal passages. And since you feel warmer in warm humid air than in dry air, you can keep your thermostat lower, which also helps prevent dry skin. A humidifier can ease symptoms of a cold, since cold dry air dries mucus, making it harder to clear from your nasal passages, while moist air helps loosen it. However, if not kept clean, humidifiers can be a source of indoor air pollution, microbes, and allergens. And if your water contains contaminants such as lead, the humidifier will spray them into the air.
At least indirectly. If the inclement weather keeps you inside and thus prevents you from exercising, inactivity can worsen arthritis symptoms. For instance, a study from Northwestern University published a few years ago found that people with osteoarthritis living in the Chicago area averaged three more hours a day of sedentary time in winter than in summer. Many people think that cold, damp weather itself worsens arthritis symptoms, but studies on this have had inconsistent results.
(a) you lose water from breathing
(b) you lose water from sweating
(c) you lose water from stepped-up urine production
(d) the cold impairs the thirst mechanism, so you’re likely to drink less
Check the next slide to see if you are right.
Cold temperature itself has little or no effect on the intensity of the sun’s ultraviolet (UV) radiation. In winter, because of the angle of the sun, the atmosphere filters out most UV. But as skiers know, it’s still easy to get sunburned in winter because UV increases at higher elevations and is reflected off snow. Clouds do not block all UV, so skiers, in particular, should use sunscreen on overcast days, too.
Cotton is a poor insulator when wet from sweat or precipitation. The key to staying warm is layering. Next to your skin should be a thin, long-sleeved base layer made of soft wool, silk, or synthetic material, which will keep you warm and help wick away sweat. Over this you can wear a middle layer made of synthetic fleece, thicker wool, or a combination of synthetic and wool. For the outer layer, depending on your activity level, you can wear an insulated zippered coat that you can vent if you become overheated. The outer shell should be wind-proof and waterproof, but breathable.
One of the most common mistakes people make when exercising in cold weather is wearing too much clothing. Even a moderate amount of brisk walking, skiing, or hiking can make you feel that it’s 30° warmer than it really is. So when you’re about to run on a 25° day, dress for about 55°. You may be a little chilled when you first go out, but you’ll warm up quickly enough. Keep in mind that if you wear several layers of clothes, you can dress for lower temperatures and then peel off layers as you warm up.
If you spend most of your time indoors and dress warmly when you go outdoors, you won’t need more calories in January than in July. However, if you are exposed to cold temperature and are inadequately dressed for it, you will shiver, which increases internal heat production and burns lots of calories. Even before you reach the point of shivering, you’ll start to burn extra calories because your metabolic rate will increase to compensate for your body’s loss of heat. Moreover, research suggests that prolonged exposure to cold stimulates brown fat, which is more metabolically active than regular fat, so it burns more calories.
But the human body doesn’t adapt nearly as well to the cold as it does to the heat. It can take weeks to adapt to the cold, and even then the acclimatization is modest. Over time, heat loss through the skin is lessened, for instance, and shivering starts at a lower body temperature. If you regularly ski, skate, or hike in the cold, you may notice some gradual acclimatization. This usually takes about two to four weeks of frequent exposure, though in some people it occurs in just a few days, and in others (notably many older people) acclimatization never occurs.
Mittens are warmer because they keep your fingers together and have less surface area from which heat can escape. For activities in which your hands sweat a lot, like cross-country skiing, you can wear special glove liners made of polypropylene or another material that draws sweat away from your skin.
But it’s still a good idea to wear a hat. It’s a myth that a disproportionate amount of heat is lost when your head is uncovered. While it is true that your head may be the main source of heat loss, that’s only because it is often the only part of your body exposed to the cold. If you went out in a bathing suit in very cold weather, you would lose no more than about 10 percent of your body heat through your head (don’t try it!). That’s what a 2006 study found when it tested subjects in cold water with and without wetsuits, sometimes with their heads out of water (in warm air) and sometimes with their heads submerged.
Hypothermia occurs when core body temperature drops excessively— usually below 95°F. Prolonged exposure to the cold without adequate clothing can cause hypothermia in anyone, but older people are at special risk because their bodies are less able to react effectively to the cold by boosting their metabolic rate and by shivering. Various medications (notably for sleep and anxiety) and alcohol can contribute to hypothermia by interfering with the heat-regulating mechanism in the brain. If you suspect someone is suffering from hypothermia, help the person warm up and get medical help. If not dealt with promptly, it can become a medical emergency.
While all of these produce carbon monoxide, which is a byproduct of combustion, more than half of deaths from unintentional carbon monoxide poisoning are due to motor vehicle exhaust—often from warming up a car in the garage. The odorless fumes can quickly fill the garage and seep into the attached house. Don’t run the motor when the car is in the garage, even with the door open. And when warming up the car outdoors, make sure the exhaust pipe is not blocked by snow.
Petroleum jelly is an emollient that helps prevent the evaporation of moisture from the skin. Glycerin is a humectant, meaning it attracts moisture and holds it against the skin. Collagen is a protein in healthy skin, but rubbing it on won’t help, since your skin can’t absorb it. Research on aloe gel as a treatment for various skin conditions has been inconsistent. In any case, nearly all commercial aloe lotions contain very little pure aloe. In general, expensive moisturizers are a waste of money.