Winter Training
Historical snowfalls, cold temperatures and short days have
been posing training challenges this winter. Recently, I have had a lot of
runners ask what the keys to marathon training in the winter are, and if cold
weather running is detrimental to their body.
Physiologic Response to Cold
Under normal circumstances and if appropriately dressed, it is
extremely rare for people to reach their cold tolerance limit. The amount
of heat one loses to the environment mostly depends on activity level and
clothing, but the balance between heat generation/loss can change rapidly
if one's activity level changes or if their clothes lose their insulative
properties (getting wet is a common example of this). As temperatures drop,
peripheral blood vessels (vessels supplying the limbs/appendices) constrict to
reduce heat loss from blood near the body’s surface in order to maintain a core
temperature of 36.5–37.5 °C or 97.7–99.5 °F through homeostasis or
thermoregulation. In other words, your body will sacrifice your limbs in
order to keep your vital organs running. A drop in just two degrees in core
temperature signals the onset of hypothermia, which can lead to confusion,
incoordination, organ failure and even death. The keys to staying safe
while running in cold weather is to cover exposed skin, stay dry, use layers
properly and protect your head and trunk. A number of studies have found
that protecting athletes' faces and keeping the trunk warm was actually more
effective at keeping the fingers warm than wearing gloves themselves. Carefully
adding and subtracting layers as needed to stay warm can take some getting used
to but will make long runs more manageable. If extremely cold, carrying
reusable hot packs is not a bad idea either.
While cold weather itself doesn’t cause illness, hypothermia
does suppress the immune system, which can lead to greater susceptibility to
infection. Vasoconstriction (narrowing of blood vessels) close to the body
surface, such as blood vessels in the nose, may compromise the nose’s ability
to filter pathogens. It is not well understood how long it takes for the immune
system to bounce back after a run; however, working out at the gym in tight
quarters with members who don’t wipe off equipment when they are done using it
may actually pose a bigger risk to one’s health (but that shouldn’t stop you
from either activity).
Last week, I had a runner ask if he could be damaging his lung
tissues when he runs outside in the extreme cold (he started coughing a lot
after his runs). Even in the very coldest of places, research has demonstrated
that runners are not at risk for damaging their lungs; by the time air
enters our lungs, it has reached body temperature. Bitterly cold
temperatures and/or dry air may act as an irritant/pathogen for some people,
which results in an exaggerated inflammatory response that promotes changes in
the airway such as coughing, increased mucus production and shortness of
breath. If this sounds like something you experience, try wearing a scarf
or neck-warmer to help warm and humidify the air before it enters your airways
so that it is less likely to cause irritation.
Heat production is directly proportional to VO2 max, meaning
the more conditioned one is, the fewer layers they will require when running in
cold temperatures. Those who are more conditioned will also be able to run for
longer periods of time safely in cold weather conditions. Scientists also
believe that shivering releases a neurotransmitter (norepinephrine) that
contributes to the body’s fight or flight response which jumpstarts the immune
system, so it has been suggested that doing some shivering before you begin
running could actually benefit the immune system.
Tips
Warming Up: Colder temperatures and slick roads can increase the risk of
muscle strains, so include a longer warm up before starting your run.
Monitoring Your Exertion: Running
in the snow and ice is similar to trail running in that it requires a lot more energy
and stabilization demands on muscles. During the winter, I would avoid
focusing on pace when the weather is rough and use heart rate and rate of
perceived exertion to keep things reasonable – it will be very important
for you to measure your body’s response to the stress load so that you are able
to recover properly.
Dressing Properly: Invest in the right gear and layer up. High tech fabrics
are essential for wicking away sweat and keeping you warm (stay away from
cotton as a base layer). Don't forget to factor in wind chill too; have an
outer windproof layer that can be vented and consider running into the wind on
your way out and returning with the wind at your back. Find a good
balaclava to protect your head, neck, and face (or a buff if you don’t like having
things over your face) and a hood on your shell top. Don’t forget about eye
protection and mittens. Consider a cold weather running shoe and wool
socks.
Remain Visible: It is still quite dark early in the morning and in the
evening. Make yourself visible to drivers and others you are sharing the
sidewalks and roads with – wear contrasting and reflective clothing.
Consider a flash light or bike lights at night or in the early morning. Always
give cars plenty of space and warning.
Traction: Try YakTrax or running in trail shoes.
Be Smart: Carry your cell phone with you, run with a buddy if possible
and let someone know your route and expected return time. Find areas to run
where there is less traffic, even if you have to drive to these areas.
Treadmill: If you are anything like me, treadmill running can be mentally
painful. I typically avoid it at all costs, but this winter weather has
made running outside dangerous at times. The lack of stimulation during treadmill running typically
had me ready to be done with my run after a mile if I don’t mix it up
a bit. Here are some strategies I use to make treadmill running more
bearable:
With
long runs, change the incline or speed every 1/4-1/2 mile (depending on the
length of the run); every other mile, check an aspect of your running form
(monitor where your foot is landing relative to your hip position, check that
your knees are staying in line with your toes, make sure your shoulders are
relaxed and that your arms are swinging parallel to one another). You can also
check your cadence; increasing step rate by five to 10 percent may be
helpful in correcting common problems. A cadence of 180 steps/min (90 steps per
foot) is a good general recommendation, but optimal step rate will vary by
individual and desired running speed.
Cross-training: Don’t forget that all of your running training doesn’t
need to be running itself. See my previous post about injury prevention and the
importance of strength and cross training.
