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Textbook
Introduction
1. Structure and function of body systems
2. Biomechanics of resistance exercise
3. Bioenergetics of exercise and training
4. Endocrine responses to resistance exercise
5. Adaptations to anaerobic training
6. Adaptations to aerobic endurance training
7. Age and sex differences in resistance exercise
8. Psychology of athletic preparation and performance
9. Sports nutrition
9.1 Standard nutrition guidelines for athletes
9.2 Macronutrients
9.3 Vitamins and minerals
9.4 Fluid and electrolytes
10. Nutrition strategies for maximizing performance
11. Performance-enhancing substances and methods
12. Principles of test selection and administration
13. Administration, scoring, and interpretation of selected tests
14. Warm-up and flexibility training
15. Exercise technique for free weight and machine training
16. Exercise technique for alternative modes and nontraditional implement training
17. Program design for resistance training
18. Program design and technique for plyometric training
19. Program design and technique for speed and agility training
20. Program design and technique for aerobic endurance training
21. Periodization
22. Rehabilitation and reconditioning
23. Facility design, layout, and organization
24. Facility policies, procedures, and legal issues
Wrapping up
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9.4 Fluid and electrolytes
Achievable CSCS
9. Sports nutrition

Fluid and electrolytes

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  • Water is the largest component of the body, comprising 45–75% of body weight.
  • Functions of water:
    • Lubrication (joints, tissues)
    • Shock absorption (brain, spinal cord)
    • Body temperature regulation (cooling via sweat)
    • Nutrient transport and waste removal
    • Blood pressure maintenance
  • The body cannot survive more than a few days without water.

Fluid balance in athletes

  • Daily fluid intake recommendations (AI):
    • Men: 3.7 L (125.1 oz)
    • Women: 2.7 L (91.3 oz)
    • Pregnant women: 3.0 L
    • Lactating women: 3.8 L
  • Athletes may require more fluids, depending on:
    • Sweat rate
    • Environmental conditions (heat, humidity, altitude)
    • Clothing and equipment
  • Sweat loss and dehydration risk:
    • Linemen in football experience high sweat rates due to heavy gear.
    • Basketball players lose around 1.6–3.5 L (54.1–118.4 oz) per game.

Preventing dehydration

  • Dehydration risks:
    • >2% body weight loss from sweat impairs performance.
    • Symptoms include increased core temperature, heart rate, and perceived exertion.
  • Assessing hydration status:
    • Urine specific gravity (USG) and plasma osmolality are effective measures.
    • Urine color is not always reliable due to vitamin and food influences.
Biomarkers of hydration status
Measure Practicality Validity (acute vs. chronic changes) EUH Cutoff
Total body water Low Acute and chronic <2%
Plasma osmolality Medium Acute and chronic <290 mOsmol
Urine specific gravity High Chronic <1.020 g/ml
Urine osmolality High Chronic <700 mOsmol
Body weight High Acute and chronic <1%

Electrolytes and performance

  • Electrolytes lost in sweat:
    • Sodium chloride (NaCl) – Most significant loss
    • Potassium, magnesium, calcium – Minor losses
  • Sodium functions:
    • Helps retain fluid and prevent cramping.
    • Sodium losses in sweat vary from 0.2 to 12.5 g/L.
  • Athletes should replace sodium losses:
    • Salty snacks, sports drinks, and broth-based soups can help.
  • Hyponatremia (low sodium levels):
    • Occurs when excess water dilutes sodium levels below 130 mmol/L.
    • Can lead to seizures, brain swelling, and death.

Fluid intake guidelines

  • Before training:
    • Prehydrate several hours before exercise.
    • Ensure USG <1.020 (indicating hydration).
  • During training:
    • Children (40 kg/88 lbs): Drink 150 mL (5 oz) every 20 minutes.
    • Adolescents (60 kg/132 lbs): Drink 250 mL (9 oz) every 20 minutes.
    • Adults: Use individualized hydration plans.
    • During prolonged activity, consume 460–690 mg sodium/L, 78–195 mg potassium/L, and 5–10% carbohydrate solutions.
  • After training:
    • Replace fluid and electrolytes lost.
    • Consume 1.5 L (50 oz) per kg of body weight lost.
    • If fluid loss is >2% of body weight, increase sodium intake.

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