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.

1. How well body supplies ATP determines performance.
2. There are 2 anaerobic & 1 aerobic sources of ATP.

Anaerobic Sources of ATP

(Anaerobic means functions without oxygen. Weightlifting is anaerobic, for example.) �

1. 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.
2. 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:
1. Lactic acid interferes with ability to turn fuel into energy;
2. Lactic acid causes fatigue;
3. 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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