C-Sig Training Series
NUTRITION FOR CYCLING
How the Body Uses Fuel for Energy
Anaerobic and Aerobic Sources
Adenosine Triphosphate (ATP) is a compound in the body which allows
the muscles to contract.
- How well body supplies ATP determines performance.
- There are 2 anaerobic & 1 aerobic sources of ATP.
Anaerobic Sources of ATP
(Anaerobic means functions without oxygen. Weightlifting
is anaerobic, for example.) �
- ATP in muscle cells is the most powerful source; it allows for short, intense
effort but is used up almost immediately; it can regenerate but loses efficiency.
- Glycolysis �Lactic Acid System� uses glycogen
that is stored in muscles & liver. (Glycogen definition:� Carbohydrates
stored in body for use as fuel) Carbohydrates are the primary fuel for intense
muscle contractions, but Lactic acid is waste product when body burns
glycogen for fuel.� When lactic acid buildup becomes debilitating, it�s called
anaerobic threshold, because:
- Lactic acid interferes with ability to turn fuel into energy;
- Lactic acid causes fatigue;
- Lactic acid draws in water, reducing blood volume, so it�s harder for
blood to deliver oxygen.
Anaerobic Threshold
You can find your anaerobic threshold by calculating your maximum heart rate,
subtract your and multiply by 85%. For example: (220 bpm � 20yrs x 85% = 170 bpm (beats
per minute). Beyond anaerobic threshold, the body can�t continue exercise for
long. This is called bonking.
Aerobic Source of ATP
Aerobic system provides an almost indefinite energy source, as Oxygen
is carried continuously to muscles from blood stream.
What Foods to Eat for Energy �(Food = carbohydrates & protein & fat)
Before a Ride
- Day before: High carbohydrate diet; lots of complete/complex carbs
(fruit, veggies, grains, whole wheat bread and pasta)
- Morning of ride:� Breakfast combining quick energy (simple carbs�OJ/jam/sugar)
& steady burn (complex carbs�cereal/whole wheat toast/fruit) &
a little protein (milk/eggs/soy)
During a Ride
Feed muscles with simple & complex carbs
- Simple carbs are easier to digest while exercising
- Complex carbs digest slower, but provide steady
energy
- Good Snacks: Fig Newton�s/banana/peanut butter & jelly
on whole wheat bread/salted pretzels/trail mix of nuts & dried fruit/energy
gels/energy bars
- How often? On long rides, eat small amounts, frequently (ex:�
� energy bar every half hour)
- If fading, take in sugary foods (simple carbs) ASAP
After a Ride��
Eat Protein, Carbs, Fat (Daily Intake�� Carbs- 60%, Fat 20-25%, Protein
15-20%)
Roles of Food Components
Protein
Eat protein within 2 hours of ride to reduce muscle soreness & begin to
rebuild muscle cells.� Choose lean protein such as white chicken or turkey,
egg whites, beans, soy products like tofu and edamame,
or low fat dairy.� Any fish and a small amount of nuts are ok, too.
Eat about 4 oz. at dinner.� Most of us eat far in excess of that amount, but
excess protein is not stored in body, unlike carbs & fat, which are stored
as energy.
Carbs�
After depleting glycogen stores, they must be replenished. Try to eat a little
carbohydrate within half an hour of ride finish, and then have more with evening
meal. Entire process of converting carbs to glycogen for storage in muscle
cells takes @ 24 hours, so do not do anaerobic exercises (weights, hill climbs
on bike) the day after a hard ride.� You can do a recovery ride on mainly flat
terrain. �
Fat �
During rides we rely on carbohydrate stores as primary fuel, then
switch to burning fat when glycogen fuel is exhausted.
- Fat is three times less efficient as a fuel than carbs (50-60%
of maximum aerobic capacity, compared to up to 85% with glycogen).��
- Choose healthy fats like canola & olive oils, nuts & seeds,
peanut butter, avocado, fatty fish like salmon and mackerel in your diet.
Using Fluids to Get Energy to Muscles
Purposes of Fluids
Our body is 60% fluids; 45% of which is stored in muscles.
Two Purposes of Fluids:
- To avoid dehydration
- To supplement body�s limited store of carbs. �A fluid deficit of
4 % (huge) can reduce aerobic capacity by 50%.
Role of Plasma
Blood delivers oxygen to muscles and takes heat away (to the skin as sweat).
Plasma is blood�s watery portion.� If plasma volume is reduced and not
replaced, it causes
- Muscle fatigue and cramps, especially in the legs (this is linked to low
electrolyte levels, which help regulate muscle contraction).
- Heat exhaustion (body can�t cool down)
- Heart Overworks (the heart beats faster to try to maintain blood volume
levels).
Before a Ride
Drink 1-2 glasses of water at least 1 hour before
During a Ride
Sip every 10-15 minutes; drink 1 bottle per hour
- Short ride need only drink water
- Long and/or intense ride, needs liquid carbs in gel or sports
drinks or fruit juice� (fruit juice not as readily absorbed as first
two) rather than just water. ��� Why?� Essential minerals are lost during
exercise ��sodium, potassium, chloride calcium A Water bottle holds
@ 20 oz; 2 bottles = 1 quart, the maximum amount the body
can absorb per hour.
- When exercising hard and in hot weather, body can loose, through sweat,
evaporation and urine, up to 2 quarts per hour.
- Cool water absorbs faster than warm; sports drink gets into blood stream
faster than water.
After a Ride
Drink lots of liquid; avoid alcohol.
Rule of thumb: Weigh yourself before ride, and after the ride drink
an equivalent amount of liquid to replace lost fluids.� Don�t worry that drinking
water gives you a weight gain.� It�s only water, not carbs or fat!
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