Amy Mason BSc Sports Science & Physiology
Unisports Centre for Sports Performance Tel 09 521 1210
Cycling in the winter provides a unique challenge
for the body. The reduction in air temperature
results in increased metabolic rate to maintain body temperature,
especially when exercising. This increase in thermogenesis (via hormonal
responses and shivering) results in an increase in oxygen consumption. At
rest, we generally consume around 3.5 mL-1.kg-1.min-1
of oxygen, however if you are cold enough to shiver, your metabolic rate
has increased oxygen consumption up to ~14 mL-1.kg-1.min-1
to increase heat production.
the Cold Affect Your Performance?
unprepared for the cold, skin and core temperature receptors stimulate a
response called peripheral vasoconstriction in cutaneous and skeletal
muscle circulation. Vasoconstriction is the narrowing of blood vessels
which decreases blood flow and therefore heat transfer from the core to
periphery. Therefore the cold essentially drives blood away from the
exercising muscles, decreasing the delivery of oxygenated blood to the
muscles and decreasing the removal of the waste products of exercise and
consequently inhibiting performance. However, vasoconstriction does not
occur in cerebral circulation and a large proportion of heat loss occurs
through the head and can amount to up to 25% of total body heat loss.
temperature decreases in the cold reducing maximal strength, power and
endurance. The superficial nerves cool and it takes more time to develop
force and reduced nerve conduction results in recruitment of fewer muscle
fibres, especially those closest to the muscle surface. Chemical reactions
slow down and ATP utilization decreases at low muscle temperatures.
core temperature is lowered, VO2max decreases (this is directly
proportional to the decrease in core temperature) from a reduction in
maximal heart rate and oxygen off-loading at the muscle tissue level.
During sub-maximal exercise metabolic rate is increased and the metabolic
cost to maintain a pace becomes greater, combined with a reduced VO2max!
Working at a higher rate results in an earlier onset of fatigue, as there
is an increased reliance on anaerobic energy production.
and Racing Recommendations:
Subcuntaneous fat –
the more the better! Yes you can put on those extra few kilos to keep warm
– you if are due to race in cold conditions that you are not used to
acclimatization at least 10 days before a competition is useful. This can
be done training at the coldest part of the day, or in an air-conditioned
room (use your imagination!).
With 25% of total
body heat loss coming from the head, wear something under your helmet,
especially if you go for the number one at the barbershop.
Go to the toilet just
prior to a race/ride. Cold temperatures increase urine formation by
decreasing tubular re-absorption of water in the kidneys.
Ignore the tough
bastard – if you are cold, rug up. You will only decrease your own
performance if you resist putting those arm or knee warmers. You will
perform better in these if the temperature drops below 15°C.
Insulate skin if you
want to race in shorts. This can be done using Vaseline or other rubs such
as Hot Stuff or Percutane. If you are prone to patello-tendonitis, it is
particularly important to keep your knees warm in winter.
Don’t wear cotton
under tops (ie. Finally throw away your souvenir nationals T-shirt from
1989) as cotton retains moisture against the skin and cools it. Instead go
for polypropylene’s that remove moisture from the skin and wearing
several thin layers of clothing is better than one bulky layer.
Cold air is denser
than warm air therefore aerodynamics are reduced = slower speeds. The
general rule for performance comparisons is a 10°C drop in temperature equals
a one minute increase in time trial time per hour.
If you are prone to
exercise-induced asthma, you will need a longer warm up in winter to
gradually allow your respiratory tract to adapt to warming the inhaled air
and attempt to prevent any problems once the race has started. Cold dry
air irritates the airways.
If riding long hills
in training remove your wind vest to allow heat loss and put it back on
before descending. It is worth taking the time to take it off so you
don’t sweat too much and rugging up before the chilly descent.
The good old
newspaper trick – putting this underneath your racing jersey is great
when racing. When you warm up you can easily get rid of it.
Eat more regularly in
racing and training, as you will be using more energy.
Before a race warm up
on a stationary trainer. This will allow the body to warm without having
to counter the wind chill factor. Warm up on the trainer, then on the road
before the race.
Spin more - spinning
increases blood flow and therefore helps increase muscle temperature.
In case of emergency
always have a few dollars in the back pocket, for that urgent hot
J., Fitch, K.D. (1992).
Textbook of Science and Medicine in Sport.
Blackwell Scientific Publications.
E.M., & Wells, C.L. (1986).
Environment and Human Performance.
Human Kinetics, Champaign Illinois.
Heat Exchange in Hot and Cold Environments.
In: Shephard, R.J., & Astrand, P.O.
Endurance in Sport. Blackwell