Carbohydrates Part III Fueling the Athlete Diabetes
Feb 02, 2016
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 Why the concern over CHO?CHO?
–
• CHO is the prime E source for –
–
–
• What types of athletes risk glycogen depletion?– – –
• 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/day8 - 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 40 normal
4 40 normal
3 20 70%
2 20 8-10g/kg males,
6-8g/kg females
1 rest same
race day
• Can be done in 2-3 days, as long as –
–
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 1-
2 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:–
–
–
–
–
Definitions• FPG: Fasting Plasma Glucose• CPG: Casual Plasma Glucose (non-
fasting)• 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 non-
insulin 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 life-threatening. – (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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