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WINTER and NUTRITION:
Fueling for cold weather exercise
Some athletes embrace winter's chill as a welcome change from exercising
in summer's heat. But others complain about hating cold weather. If
that's your stance, remember that exercising with proper nutrition (and
layers of dry clothing) offers the opportunity to chase away the chills.
After all, an aerobic workout can increase your metabolism by 7 to 10
times above the resting level. This means, if you were to exercise hard
for an hour and dissipate no heat, you could raise your body temperature
from 98.6° to 140° F. (You'd cook yourself in the process!) In the
summer, your body sweats heavily to dissipate this heat. But in the
winter, the warmth helps you survive in a cold environment. Runners can
enjoy a tropical environment in their running suit within minutes of
starting exercise...
Because food provides the fuel needed to generate this heat, the right
sports diet is particularly important for skiers, skaters, runners and
other athletes who are exposed to extreme cold. The following article
addresses some common questions and concerns about winter and nutrition
and offers tips to help you enjoy the season.
For safety sake, winter athletes should always carry with them some
source of fuel in case of an unexpected slip on the ice or other
incident that leaves them static in a frigid environment. Winter
campers, for example, commonly keep a supply of dried fruit, chocolate
or cookies near by for fuel if they wake up cold in the middle of the
night. You want to have an emergency energy bar tucked in your pocket,
just in case...
Why do I feel
hungrier in the winter than in the summer?
A drop in body temperature stimulates the appetite and you experience
hunger. Hence, if you become chilled during winter exercise (or when
swimming, for that matter), you'll likely find yourself searching for
food. Eating "stokes the furnace," generates heat, and helps warm your
body.
Food's overall warming effect is known as thermogenesis (that is, "heat
making"). Thirty to sixty minutes after you eat, your body generates
about 10% more heat than when you have an empty stomach. This increased
metabolism stems primarily from energy released during digestion. Hence,
eating not only provides fuel but also increases heat production,
warmth.
Do I burn more
calories when I exercise in the cold?
Cold weather itself does not increase calorie needs. You don't burn
extra calories unless your body temperature drops and you start to
shiver. (And remember: the weather can actually be tropical inside your
exercise outfit.) Your body does use a considerable amount of energy to
warm and humidify the air you breathe when you exercise in the cold. For
example, if you were to burn 600 calories while cross-country skiing for
an hour in 0° F weather, you may use about 23 percent of those calories
to warm the inspired air. In summer, you would have dissipated this heat
via sweat. In winter, you sweat less.
If you are wearing heavy clothes, you will burn a few more calories to
carry the extra weight of skis, boots, heavy parka, snow shoes. The Army
allows 10% more calories for the heavily clad troops who exercise in the
cold. But the weight of extra clothing on, let's say, winter runners is
generally minimal...
Why do I find myself
shivering when I get cold?
Shivering is involuntary muscle tensing that generates heat and offers a
warming effect. When you first become slightly chilled (such as when
watching a football game), you'll find youself doing an isometric type
of muscle tensing that can increase your metabolic rate two to four
times. As you get further chilled, you'll find yourself hopping from
foot to foot and jumping around. This is Nature's way to get you to
generate heat and warm your body. If you become so cold that you start
to shiver, these vigorous muscular contractions generate lots of
heat--perhaps 400 calories per hour. Such intense shivering quickly
depletes your muscle glycogen stores and drains your energy. This is
when you’ll be glad you have some emergency food in your pocket!
What's a big
nutritional mistake made by winter athletes?
Failing to drink enough fluids is a major problem among winter
athletes—hockey players, skiers, runners and winter hikers alike. Cold
blunts the thirst mechanism; you'll feel less thirsty despite
significant sweat loss (if you overdress), to say nothing of respiratory
fluid loss. That is, winter athletes need to consciously consume fluids
to replace the water that gets lost via breathing. When you breath in
cold dry air, your body warms and humidifies that air. As you exhale,
you lose significant amounts of water.
Some winter athletes purposefully skimp on fluids because urinating can
be problematic—too much hassle to shed layers of clothing (ski suit,
hockey gear, snow pants, etc.) Yet, dehydration hurts performance and is
one cause of failed mountaineering adventures.
What's best to eat
to warm myself up?
If you become chilled by the winter weather, as can easily happen if
you—
--wear sweaty, wet clothing that drains body heat,
--fail to wear a hat (30 to 40% of body heat can get lost through the
head), or
--drink icy water (from a water bottle kept on your bike or outside
pocket of your back pack when winter hiking),
the best way to warm yourself up is to consume warm carbohydrates—hot
cocoa, mulled cider, and steaming soup, as well as oatmeal, chili, and
pasta. The warm food, added to the thermogenic effect of eating,
contributes to rapid recovery.
In comparison, cold foods and fluids chill your body. Research subjects
who ate a big bowl of ice cream in five minutes experienced a drop in
fingertip temperature of 2° F in the first five minutes, 5° in 15
minutes. In summer, this cooling effect is desirable, but in winter, hot
foods are the better way to warm yourself. Bring out the thermos of
soup!
Why do I gain weight
in the winter?
Some people eat more because they are bored and less active. Instead of
playing tennis, they are eating mindlessly in front of the TV. For
others, the change of seasons has a marked affect upon their mood (known
as seasonal affective disorder, or SAD). Changes in brain chemicals
increase carbohydrate cravings and the desire to eat more. Holiday
temptations also contribute to weight gain. A study of 195 people
indicates they gained on average 0.8 pounds in the six weeks between
Thanksgiving and New Years. Overweight and obese people gained even
more, with about 14% of the group gaining more than five pounds. The
problem is, very few of the subjects lost those holiday pounds. Hence,
yearly holiday weight gain becomes a major contributor to America’s
obesity problem ... that's eight pounds in ten years.
One weight management solution is to stay active in the winter. By
investing in proper clothing, you'll be able to stay warm from head to
toe. You'll benefit from not only being able to enjoy exercise but also
from sunlight—a good way to battle winter depression (and attempts to
cheer yourself up with food). Winter exercise is an asset for managing
heath, weight and the winter blues. The tricks are to dress right, fuel
well, prevent dehydration -- and you’ll stay warm!
Sports nutritionist
Nancy Clark, MS, RD offers nutrition consultations to casual and
competitive athletes at her private practice in Healthworks
(617-383-6100), the premier fitness center in Chestnut Hill MA. Her
Sports Nutrition Guidebook ($23) and Food Guide for Marathoners ($20)
can help you improve your sports diet. Both books are available at
www.nancyclarkrd.com or by sending a check to PO Box 650124, West Newton
MA 02465. |
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Ray Lauenstein is the author of
Baseball: Playing Outside the Lines and The Making of a Student
Athlete. He also holds a Masters Degree in Sport Psychology and gives
seminars on Mental Skills Training and the Recruiting Process. If you would
like him to speak to your team, booster club or other group please contact him
via the online form or call 1-617-835-1836.
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