|
Estimating
your Caloric replacement needs is always a challenge. And as
CHANGE
IN WEIGHT (IN LBS) = (CALORIES BURNED - CALORIES CONSUMED)/3500
you
will see the results reflected in the bathroom scales.
Regular
physical exercise will help to protect your muscles (at the expense
of fat) during periods of negative caloric balance so you will
not lose significant muscle mass even if you underestimate your
calorie needs. However, if you overshoot on the calorie replacement,
and especially if you have been exercising at a slow pace (which
will preferentially burn fat calories while maintaining muscle
glycogen stores),any post ride carbohydrate loading may find muscle
glycogen stores already "filled" and any additional
carbohydrate calories will be converted directly into fat.
The
bottom line
Eat
a high carbohydrate diet (60 to 70% carbohydrate, low in fat), the
diet that is best for endurance performance . Do weight training
to maintain upper body muscle mass. And keep an eye on the bathroom
scale to determine if you have estimated replacement needs correctly.
With a regular exercise program, a modest weight gain should be
in muscle mass and any weight loss from fat.
Fluids
Although
water does not provide caloric energy, adequate hydration is at
least as important to athletic performance as the food you eat.
One of the biggest mistakes of many competitive athletes is failing
to replace fluid losses associated with exercise. This is especially
the case in cycling as rapid skin evaporation decreases the sense
of perspiring and imparts a false sense of only minimal fluid
loss when sweat production and loss through the lungs can easily
exceed 4 pints per hour. For a successful ride, it is essential
that you start off adequately hydrated, begin fluid replacement
early, and drink regularly during the ride. In fact, a South African
report on two groups of cyclists, one consciously rehydrating,
the other not, exercising at 90% of their maximum demonstrated
a measurable difference in physical performance as early as 15
minutes into the study.
Total
body fluid losses during exercise lead to a diminished plasma
volume (the fluid actually circulating within the blood vessels)
as well as a lowered muscle water content. As fluid loss progresses,
there is a direct effect on physiological function and athletic
performance. An un-replaced water loss equal to 2% of base line
body weight will impact heat regulation, at 3% there is a measurable
effect on muscle cell contraction times, and when fluid loss reaches
4% of body weight there is a measurable 5-10% drop in performance.
In addition, one study demonstrated that this performance effect
could persist for 4 hours after re-hydration takes place - emphasising
the need to anticipate and regularly replace fluid losses. Maintaining
plasma volume is one of the hidden keys to optimal physical performance.
So make it a point to weigh yourself both before and after the
ride - most of your weight loss will be fluid, and 2 pounds is
equal to 1 quart. A
drop of a pound or two won't impair performance, but a greater
drop indicates the need to reassess your on the bike program.
And use the post ride period to begin replacement of any excess
losses. If you do so, you will be well rewarded the next time
out.
But
as a word of warning to those who practice the philosophy of "if
a little is good, a lot is better", there are also risks with
overcorrecting the water losses of exercise. There have been reports
of hyponatremia (low blood sodium concentration) with seizures in
marathon runners who have over replaced sweat losses (salt and water)
with pure water. This risk increases for longer events (more than
5 hours).
Weighing yourself regularly will help you tailor YOUR OWN PERSONAL
replacement program. A weight gain of more that 1 or 2 pounds will
indicate that you are overcorrecting your water losses and may be
placing yourself at risk for this unusual metabolic condition.
|
