Tuesday, February 5, 2013

Running Outside in Winter Might Make Us Healthier



Although there is no question that cold weather can be hard on your body in some ways, there is research that suggests that winter's cold, rather than simply contributing to illness, can often be good for you. It turns out, depending on several factors, winter weather can play a role in either sickness or health. Here we explore why this might be so, and also suggest a few emerging winter sports that have caught on in recent years, suiting varying degrees of both fitness and adventurousness. This follows from the fact that, in particular, moving your body outdoors in the cold offers several distinct benefits.

Types of body fat. There are two types of fat in the human body: brown fat and white fat. Brown fat is the heat-producing, calorie-burning fat that babies need to regulate their body temperatures. Most of it disappears with age, but adults retain some brown fat. Dutch researchers reported findings in 2009 that showed that moderately cool temperatures of 61 degrees Fahrenheit activated brown fat in 23 of 24 study volunteers. This is a good thing because brown fat burns calories more efficiently than white fat, and so may help control weight. And so when you get chilled this winter, take some consolation that at least you're firing up those brown fat cells.

The good news from cold research. In fact, the use of cold temperatures for medical purposes is taken quite seriously in certain parts of the world. Several years ago, Finnish researchers reported the results of a study of 10 women who, for three months, took cold-water plunges (20 seconds in water just above freezing) and also submitted to whole-body cryotherapy sessions. Whole-body cryotherapy was developed in Japan to treat pain and inflammation from rheumatoid arthritis and other conditions. With cryotherapy, patients spend one to three minutes in a room cooled to a shocking -166 degrees Fahrenheit. Blood tests taken during the study showed a two-to threefold jump in norepinephrine levels minutes after cold exposure. Norepinephrine is a chemical in the nervous system that performs many functions, including a likely role in pain suppression. This is promising news for the effectiveness of cold therapy to treat certain types of pain.

Additionally, it's widely thought that cold temperatures perform a public health service by killing off disease-carrying insects and microorganisms. A lesser known but very real worry about climate change is that rising temperatures will cause winter to lose much of its pestilence-fighting ability, but clearly the sometimes bitter winter weather has its upside.

The not-so-good news. Still, also in 2009, French researchers found that the increase in systolic blood pressure that occurs during the winter was especially pronounced in people ages 80 and older. Numerous studies have shown that death rates peak at this time of year. Blood pressure increases during the winter regardless of age, and by some estimates 70 percent of the wintertime increase in the death rate can be traced back to heart attacks, strokes, and other cardiovascular causes of death.

The fastidious killing off of certain microorganisms notwithstanding, flu season is a winter event, and flu viruses can spread more readily once the air is dry and chilly. Cold weather and respiratory illness sometimes do go hand in hand. Research has shown that cold spells are reliably followed by upticks in the number of deaths from respiratory disease. Some of this may have to do with a few infectious organisms, like flu viruses, thriving in colder temperatures, but there's also evidence that exposure to cold temperatures suppresses the immune system, so the opportunities for infection increase.

A study published in The New England Journal of Medicine in the late 1970s famously debunked the belief that the common cold is linked to cold exposure, but British cold researchers have maintained that there is a cold air connection to the common cold. Their hypothesis is that cold air rushing into the nasal passages makes infections more probable by diminishing the local immune response there.

However, our bodies adapt to cold temperatures pretty well. When we encounter cold air or water, the network of blood vessels in the skin constricts, and blood is hastily sent to the interior. That response adds to the insulating power of the skin because there's less heat lost from blood circulating near the surface. It also protects vital organs against the falling temperature. But this rerouting of blood makes fingers, toes, and other peripheral parts of the body like the nose and ears vulnerable to frostbite, which occurs when the fluids in tissue freeze. Under the right conditions, blood vessels in the skin will open and close in an oscillating pattern, so skin temperatures rise temporarily, especially in the fingertips.

The research suggests that the sedentary are the most vulnerable to the negative effects of cold weather. In the balance, then, winter is no time to let exercise fall off. See Three Indoor Workouts for Winter in this issue for several indoor fitness options. Here are a few novel winter sports trends that may peak your interest--and keep you warm in the great outdoors this holiday season and beyond.

Telemark. Hardly new but gaining popularity in recent years, telemark skiing was invented in 1868 by Sondre Norheim, a Norwegian farmer from the province of Telemark. This wonderfully aesthetic form of skiing is a hybrid of alpine and cross-country skiing, spruced up with a touch of freestyle. Telemark bindings leave the skier's heel free to make turns with flexed knees. With wide skis, the skier moves more fluidly than traditional downhill, resulting by most accounts in a rather exhilarating experience. This Norwegian invention adds a touch of elegance to board sports and is ideal for skiers looking less for speed than for perfect balance and a leisurely ride.

Snow kiting. If you're familiar with kite surfing, the summer cousin of snow kiting, you'll understand the idea of this sport right away. In the summer, this is an activity that hurls you through the water on a surfboard while attached to a traction kite. The kite provides balance and considerably softer landings against gravity, making it perfect to attempt while going downhill on snow as well. It turns out that practitioners of both sports see careening downhill on snow skis or a snowboard easier to learn than the summer surfing version.

Yet thrillingly, in snow kiting the slightest breeze can turn a small mogul jump into a giant leap through the air. Jumps can reach 50 feet in height and five times that in length. Some experienced kiters even use it as a natural ski lift, riding uphill with wind power and then coming downhill gently, as if walking on air.

Speed riding. A more extreme version of snow kiting, speed riding invokes a combination of parachuting, paragliding, and skiing to even further blur the boundary between snow and sky.

Attached to a paraglider and wearing skis, riders leap 30 feet or more over rocky outcrops before skiing down the slope to the next leap into the unknown. The sport requires real expertise and much practice. But that makes it no less addictive if you're among the many people willing to take lessons and put the time in to learn. The French Federation of Free Flight, which also affiliates paragliding, delta plane, and snow kiting, offers a directory of resorts that provide lessons for the average skier. Such a winter getaway would make for a novel vacation, to say the least. Speed riding, executed at its best, like the equally flamboyant practice of parkour, approaches art.

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