Download Carbohydrates – Part III

Carbohydrates Part III
Fueling the Athlete
Diabetes
• Recall:
– When intensity of exercise goes up, use of
what fuel goes up? Why?
– Over time (duration), use of what fuel goes
up? (assuming there’s plenty of oxygen
available) Why?
CHO and the Athlete
– Why the concern over
CHO?
–
• CHO is the prime E source for
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• What types of athletes risk glycogen
depletion?
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• What happens when an athlete starts to
run out of glycogen?
THE TIME TO FATIGUE IS
DIRECTLY RELATED TO
INITIAL GLYCOGEN
STORES
• So the goals of feeding CHO to these
athletes are to
– Maximize glycogen stores before the event
– Minimize losses during the event
– Re-synthesize glycogen after the event
Daily CHO Needs for Athletes:

60% CHO recommended

(up to 70% during heavy training)
OR
 If exercise < 60 minutes per day
5 g/kg (typical Am. Diet = 4 g/kg)
 If exercise 60 - 90 minutes/day
6-7 g/kg
 If training >90 - 120 minutes/day
8 - 10 g/kg
 If extreme program (6-8 hours/day - cycling)
10-12 g or more/kg
Pre-Endurance Event:
Glycogen Supercompensation
• AKA CHO-loading
• For events  90 min. OR intermittent
• NOT recommended for those w/ diabetes
or known heart disease
• Can nearly double muscle glycogen stores
:
day 6
90 min (70-75% VO2max) 60% CHO (nl)
5
4
3
2
40
40
20
20
1
race day
rest
normal
normal
70%
8-10g/kg
males,
6-8g/kg
females
same
• Can be done in 2-3 days, as long as
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PRE EVENT MEAL
• Best: Consume 4 hours prior to event
– 4-5 g/kg body weight
Example: 60kg athlete:
• If 4 hrs before event isn’t feasible, consume less 12 hours before the event (1-2g/kg).
– Foods that are easily digested and low in fat/fiber
– Glycemic index?
During Event:
Minimizing losses,
Maintaining blood glucose levels
• 15 to 20g CHO every 15-20 min.
– (or 30-60g CHO per hour of exercise)
–
– at optimal concentration
• Glycemic index?
Post-Event:
Glycogen Repletion: Biphasic
• Rapid initial response – to baseline
• Slower 2° phase: to above normal levels
• Proportional to CHO intake
–
–
–
– protein-CHO combination may increase
glycogen re-synthesis
• Important for athletes who have events
or training sessions within 24-48 hours
of activity
• (Repletion usually takes ~ 48h for events
lasting >90 minutes.
– Can take up to 5 days
Sports Drinks
• 6-8% CHO solution is best (most sports
drinks)
–
–
• Glucose polymers in sports drinks are
quickly absorbed
•
– Optimal post exercise fluids should be high
glycemic index fluids (low fructose)
Diabetes Mellitus
Diabetes Mellitus:
• A group of metabolic diseases
characterized by hyperglycemia
• Resulting from defects in insulin
secretion, insulin action, or both.
(ADA Website)
Approximately half the people with
diabetes are undiagnosed
Major cause of:
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Definitions
• FPG: Fasting Plasma Glucose
• CPG: Casual Plasma Glucose (nonfasting)
• OGTT: Oral Glucose Tolerance Test
(75g)
• Hemoglobin A1c (glycated hemoglobin,
glycosylated hemoglobin)
– Indicates average BG levels over approx. 3
months. % of total Hgb attached to glucose
– Normal: 4-6% (DM: >8%)
Diagnosis
(don’t memorize - just remember that
having hyperglycemia once is not
diagnostic, and can happen for reasons
other than diabetes)
• Pre-Diabetes (new diagnosis)
– FPG 100-125mg/dl
– OGTT 2h 140-199 mg/dl
• Diabetes
– Confirmed FPG  126 mg/dL
– CPG  200 mg/dl + symptoms
– OGTT (75g glu) 2hPG  200 mg/dl
Type 1 Diabetes
• AKA “juvenile onset diabetes,” or
“insulin-dependent diabetes”
•
• Most diagnosed < age 20
• Damage to beta cells of pancreas 
• Dependent on exogenous ___________
• Meals timed w/ insulin doses to regulate
blood glucose
– CHO control
Type 2 Diabetes
 AKA “adult onset diabetes” or noninsulin dependent diabetes.

 Pancreas produces some insulin, but
 Most diagnosed > age 40…
  Risk:
 gestational diabetes



2
Consequences of Diabetes
• Hyperglycemia
– Dehydration
– Excessive thirst and urination
– Excessive hunger
• Glycosuria (glu spills into urine:
>180mg/dl)
• Ketosis (Type 1)
– Cells aren’t receiving glucose/amino
acids due to inadequate or no insulin
– Fat is mobilized for E
– Liver responds (to fat mobilization) by
producing ketone bodies
– Accumulate in blood  ketoacidosis
– Severe ketoacidosis  _________
• Nonketotic Coma (Type2) – coma
due to extremely high blood
glucose
• Hypoglycemia – too much
insulin/mediacations, strenuous
activity, inadequate food intake,
alcohol intake, etc. Can be lifethreatening.
– (note: hypoglycemia resembles
intoxication—Type 1 pts should wear ID
bracelets)
Symptoms Of Hypoglycemia
– Shakiness, dizziness, sweating
– Hunger
– Headache
– Pale skin color
– Sudden moodiness or behavior
changes, such as crying for no
apparent reason
– Clumsy or jerky movements
– Difficulty paying attention, or
confusion
– Tingling sensations around the
mouth
Chronic Complications of
Diabetes
• Cardiovascular Disease
• Microangiopathies (disorders of
capillaries)
– Kidneys
– Retina
• Neuropathy
– loss of sensation in extremities
– gangrene  amputations
Treatment
• Type 1: Diet, exercise, insulin
• Type 2:
– Treatment includes weight loss
– Meal planning:consistent CHO
intake throughout the day
– Medications: Oral hypoglycemic
agents (OHA)
– 40% will require exogenous insulin
• Both types:
Effects of Exercise
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