SLUSH IT OUT
SODA, SO GOOD?
LOADING UP ON SODIUM bicarbonate (aka baking soda)
before a race in the heat could help your body to deal with the
conditions, says nutritionist Nigel Mitchell. ‘I use it with my
athletes because it hyper-hydrates the body. In effect, you
enjoy a blood plasma increase, so as well as preventing
dehydration, it helps with blood flow and circulation.’
Research shows that the optimal dose is around 0.3g per kg
of body weight, so for a 70kg athlete, you’re looking at 21g.
You can weigh out the sodium bicarb before mixing with
water, or consume capsules such as Sodibic. As for timing,
traditionally it was advised to take the bicarb two
to three hours before your race to time for the
maximum effect on blood pH. However,
a study by Dr Andy Sparks of Edge Hill
University in Ormskirk showed that peaking
time for some comes after just 75 minutes.
Mitchell warns that this is not the right
strategy for multi-day racing: ‘The
downside is that most athletes will be
about 1kg heavier the next day because
of the sodium retaining fluid.’PRIOR TO THE 2008 Beijing
Olympics, sports scientists
from national federations
around the globe had one
major issue to contend
with: how to manage the
predicted intense heat
and humidity. After much
experimentation, The
Australian Institute of Sport’s
renowned nutritionist,
Louise Burke, discovered that
athletes drinking 700-1,000ml
of an ice slushie before
competition saw a 0.5C
drop in body temperature,
which remained after a
30-minute warm-up.
Burke also added glycerol to
the slushies to improve fluid
retention, because previous
studies had shown that
consuming glycerol, which
you can pick up from Boots for
£1.49 a bottle, can boost fluid
retention by up to 50 per cent.
The doping watchdog WADA
was so convinced of this
combination’s performance-
boosting effects that it
banned the use of glycerol
in 2010 owing to what it
called its ‘plasma-expanding’
qualities. (The ban was lifted
in January 2018.)
Measurements of the
performance benefits from
the reduction in baseline
temperature have ranged from
three to eight per cent, but the
effects do wear off relatively
quickly so it’s more applicable
for distances under 10K.
This is one to experiment
with before a big race day
because to get the cooling
effect you must swallow
the ice without swilling it
around in your mouth
(which speeds up its
melt rate) and this can
upset some stomachs.COOL
RUNNINGS
SO IF DOWNING ice
keeps you cool, should
you keep sipping slushie
on the run? No, according
to research carried out by
New Zealand exercise
physiologist Paul Laursen.
In his study, cyclists
undertook time trials in an
environmental chamber
programmed to a constant
temperature of 35C while
drinking either fluid at a
temperature of 4C, or an
ice slushie at -1C.
The cyclists were
slower and produced less
average power drinking
the slushie, though other
physiological metrics
such as heart rate and
sweat rate showed no
significant difference,
while core temperature
rose 0.02C during the
slushie trial compared
with 0.4C in the fluid trial.
‘That leads us to believe
it’s a perceptual discom-
fort issue,’ says Laursen.
‘The athletes, especially
at high intensity, found
the slushie uncomfortable
to consume.’
Whatever the cause
and effect, the results
show that drinking cooler
fluids rather than ice
during your run is the
right strategy. A Floe
bottle or similar product
that maintains the fluid’s
temperature for a long
time is ideal.SUMMER RUNNIN’
SEPTEMBER 2019 RUNNERSWORLD.COM/UK 045