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| Source: Philly.com |
The past week I have not been walking to work
due to the frigid temperatures and frostbite warnings. However, I normally do
walk most days of the throughout the winter (on days it is >20˚F). People think I am crazy, but I say
it is no different than when I was in college at Penn State- walking over a
mile to class on a day it was below freezing was no big deal, it was actually
the norm for PSU students. I remember some days by the time to get to class I would want to cry
because I was so cold that my face hurt and eyelashes were frozen. Or, we would
be tailgating then sitting on the metal bleachers for four hours at night
with temperatures in the teens and twenties. Ahhh the glory days! But hey, it
was fun and it made me tougher!
Walking in the cold certainly makes me appreciate heat and being comfortable. Just as with exercise, being
uncomfortable isn't necessarily a bad thing, it can make you stronger (mentally
and physically!). I actually have found that now that I am not living up in Happy
Valley and don't have long periods of exposure to the cold anymore, I am more
of a wuss when it comes to cold temperatures. I really think I could tolerate
the cold better when I was in college than I do now... so perhaps I had more brown fat back then?
Researchers have long known that shivering is a protective
function of the body and works to increase the body’s temperature by burning
more calories. Some estimate that the metabolic rate can increase almost 5x
when shivering, leading the body to potentially expend over 400 calories an
hour. New research suggests that exposure to just slightly less than
comfortable temperatures really can boost your calorie burn through
Non-Shivering Thermogenesis (NST). NST is when the body increases its
temperature (without shivering) in cool, but not frigid conditions. Research
has shown that people gradually adapt and build up more brown fat when exposed
to cold regularly. Brown fat is metabolically active fat and burns calories to
produce heat, rather than storing calories like the standard white fat. Some
estimate that brown fat can account for 30% of the calories one burns in a day.
In one Japanese study, subjects sat in a cooler room (62.6˚F) for
2 hours a day for six weeks. After the six weeks, the test subjects had decreased
their body fat by 5% compared to those exposed to traditional room temperature
settings. Furthermore, test subjects burned more calories when exposed to cold
than the control subjects. In a new study, researchers had subjects sit in a
room at 59˚F for six hours each day over 10 days. At the end of the 10 days,
subjects had an increase in their brown fat and noticed they could tolerate
cold better than they previously could.
My Recommendations: Experts still are not
sure how long you need to be in a cold setting to burn x amount of calories,
but the studies are showing that slightly cooler than comfortable temperatures
can make a difference in your levels of brown fat and calorie burn. So, next
time you are tempted to stay inside on a cold day, get outside for a bit and go
for a walk (unless there is a frostbite warning!). Maybe learn to appreciate
your freezing cold office and realize it may actually be benefitting you. My
motto is that you never experience the joys in life (i.e: heat) without first
experiencing the pains (i.e: cold). However, if you are an elderly person or
have significant health problems like a heart condition, exposing yourself to
cold may be something you want to talk to your doctor about.
References:
1. J Clin Invest. 2013;123(8):3404–3408. doi:10.1172/JCI67803.
2. Trends in Endocrinology & Metabolism, van Marken Lichtenbelt et al.: "Cold exposure – an approach to increasing energy expenditure in humans."
3. Picture- Philly.com
4. http://woodburygazette.com/burn-more-calories-in-the-winter-or-summer-months-p552-106.htm
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