Nutrition Module 5

Target Heart Rate (THR) Calculation Formula

220-age

target zone= 60-90% MHR

Pulse Counting Method for Heart Rate

Count the number of heartbeats (pulse) for 10 seconds and multiply by 6

Aerobic Workout Frequency and Duration Recommendations

20-60 minutes per session, 5 days per week (preceded by a 5-10 minute warm-up and followed by a 5-10 minute cool-down)

Resistance Training Frequency Recommendation

2-3 days per week

Primary Medical Screening Criteria Before Exercise Initiation

Consult a physician if previously inactive AND: Male > 40 years old OR female > 50 years old OR having a history of hypertension, diabetes, or cardiovascular disease

Immediate Energy Sources (0-10 seconds)

Stored ATP: 2-4 seconds (anaerobic)

Phosphocreatine (PCr_: ~10 seconds (anaerobic breakdown into creatine + phosphate to re-form ATP)

Anaerobic Glucose Breakdown (30 seconds to 3 minutes)

Fuel source: carbohydrates (glucose)
Byproduct: lactic acid (causes muscle fatigue)
Example event: 400-meter sprint

Aerobic Energy Pathways (2 minutes to 3 hours)

Occurs under oxygenated conditions; supplies 95% of the body’s ATP needs during endurance activities (e.g., cross-country running)

Glycogen Source: Muscle vs. Liver by Duration

Events < 30 minutes: utilizes muscle glycogen directly

Events > 1 hour: utilizes liver glycogen (released into blood). Depletion causes “bonking” or “hitting the wall”

Carbohydrate Intake During Prolonged Exercise (>1 hour)

30-60 grams of carbohydrates per hour

Primary Fuel Source During Rest and Low-Intensity Activity

Fat (broken down into 3 fatty acids and 1 glycerol molecule). As fitness improves, fat utilization increases

Daily Carbohydrate Requirements for General Fitness vs. Endurance

General recommendation: ~60% of total calories (minimum 5g/kg of body weight daily)

Endurance athletes (> 60 min activity): 7-10 g/kg of body weight daily

Glycogen Storage Capacity per 100g of Muscle

Untrained muscle: 13 grams

Trained muscle: 32 grams

Carbohydrate-loaded muscle: 35-40 grams

Carbohydrate Loading Protocol

Begins 1 week prior to events > 60 min. Daily carbohydrate percentage increases up to 70% of total calories while exercise intensity tapers down to zero the day before.

Side effect: muscle stiffness/heaviness (due to excess water storage)

Daily Dietary Fat Recommendations for Athletes

Approximately 35% of total calorie intake

Protein RDA vs. Athlete Requirements

Sedentary Adult RDA: 0.8 g/kg

Athletes: 1.0-1.6 k/kg

Muscle maintenance: ~1.2 g/kg

Adverse Effects of Excess Protein Intake

Increases urine production, leading to dehydration and fatigue

Body Fat Percentage Standards: Average vs. Athlete

Males: Average = 8-24%, Athlete = 5-18%

Females: Average = 20-35%, Athlete = 17-28%

Energy Expenditure and Caloric Deficit Guidelines

Moderate physical activity burns: 5-8 kcal/minute

Caloric reduction for safe weight loss: decrease intake by 200-500 calories/day

Risk threshold: intake < 1400 kcal/day makes meeting micronutrient needs difficult

Female Athlete Triad

Disordered eating (low BMI)

Amenorrhea

Osteoporosis

Ergogenic Aids: Approved vs. Harmful/Banned

Permissible: Vitamins/minerals, energy bars, sports drinks, meal replacement drinks

Banned: Anabolic steroids, growth hormones, GHB, blood doping

Daily Fluid Baseline & Pre/Post-Exercise Fluid Replacement

Daily baseline intake: 11-15 cups/day

2-3 hours before exercise: 1.5-2.5 cups

Post-exercise replenishment: 2.5-3 cups of water per pound of body weight lost

Critical Weight Loss Threshold & Hydration Indicators

Critical Threshold: Body weight loss > 3% due to sweat severely impairs performance and risks fatal heat illness

Hydration status indicator: Clear to pale yellow urine = hydrated; dark yellow = dehydration risk

Differential Diagnosis: Heat Exhaustion vs. Heat Cramps vs. Heatstroke

Heat Cramps: Painful muscle spasms when fluid is replaced but sodium remains low

Hat exhaustion: High sweat, dizziness, nausea/vomiting, cool/flushed skin

Heatstroke: body temp reaches > 104* F, sweating STOPS, hot/dry skin, confusion, seizures, coma

Indication for Sports Drinks vs. Plain Water

Events < 60 minutes: Plain water is best

Events > 60 minutes: Sports drinks are recommended to supply carbohydrates (glucose) and replace lost electrolytes (sodium and potassium)