4.3 Nutrition, Hydration & Sleep

PA8 task 0104 asks the AT to optimize wellness, which includes what athletes eat, drink, and how they sleep. The AT is not a registered dietitian and does not independently treat eating disorders, but the AT is the person who sees the wrestler’s rapid cut, the runner’s missed meals, the gallon-jug cult, and the 5 a.m. bus after a 1 a.m. phone scroll.

---

Energy Availability and Carbohydrate for Training

Energy availability (EA) is the dietary energy left after exercise energy expenditure, usually expressed relative to fat-free mass. When EA is too low for too long—whether from undereating, excessive expenditure, or both—athletes can develop Relative Energy Deficiency in Sport (REDs). The International Olympic Committee (IOC) 2023 consensus (Mountjoy et al.) emphasizes that REDs can affect any sex, sport, or level. Consequences span menstrual or endocrine disruption, low bone density and stress-fracture risk, impaired immunity, cardiovascular effects, gastrointestinal problems, and declining performance. The older “female athlete triad” (low energy availability, menstrual dysfunction, low bone mass) is now understood as one presentation inside REDs, not a female-only diagnosis.

The AT’s job is screening and referral, not running an IOC REDs CAT-2 workup alone. Red flags: unexplained performance drop, recurrent bone stress, missed periods or low libido, rigid “clean eating,” rapid weight loss, bathroom patterns after meals, cold intolerance, and a coach-driven weight culture. Refer to the team physician and a sports dietitian / eating-disorder–qualified clinician. Do not prescribe a more aggressive deficit because the athlete “looks fine” or “wants to make weight.”

Carbohydrate is the primary training fuel for moderate-to-high intensity work. The International Society of Sports Nutrition (ISSN) and sports-nutrition reviews typically place:

• ~5–8 g/kg/day for athletes in moderate training volumes
• 8–12 g/kg/day when the goal is to maximize glycogen during high-volume or multi-session days
• About 30–60 g/hour of carbohydrate during prolonged high-intensity exercise lasting more than about 60–70 minutes (often as a 6–8% carbohydrate-electrolyte solution)

Endurance athletes who slash carbohydrate to “eat clean” while stacking mileage are the REDs and bonk pipeline. Protein does not replace glycogen.

---

Protein Timing Without Magical Powders

The ISSN protein-and-exercise position stand (Jäger et al., 2017) is the number set to know:

• 1.4–2.0 g of protein per kg body weight per day is sufficient for most exercising people to support muscle protein synthesis and maintenance.
• Per feeding, about 0.25 g/kg of high-quality protein, or an absolute 20–40 g, is a typical target.
• Spreading feedings about every 3–4 hours is more useful than a single 80 g shake at midnight.
• Food-first sources that supply essential amino acids are the default; powder is a convenience tool, not a requirement.

Higher intakes appear in hypocaloric or heavy-resistance contexts in later ISSN reviews; do not invent a universal “2.2 g/kg or you catabolize” rule for every high-school athlete. Exam trap: recommending a specific supplement brand or claiming every athlete must buy a whey isolate to recover.

---

Hydration: Sweat Rate, Not a Gallon Mandate

The NATA 2017 position statement Fluid Replacement for the Physically Active (McDermott et al., Journal of Athletic Training, 52(9):877–895) replaces the old “everyone drinks 7–10 oz every 10–20 minutes” script with individualization.

Sweat rate (L/h) = [pre-exercise body mass (kg) − post-exercise body mass (kg) + fluid consumed (L) − urine (L)] / hours of exercise.

Adult sweat rates during exercise commonly range from about 0.5 to 4.0 L/h. Voluntary drinking typically replaces only about two-thirds of sweat losses. Targets:

• Begin as close to euhydration as practical (+1% to −1% of a valid baseline mass).
• Limit in-session body-mass loss to <2% for high-performance and heat-safety goals.
• Do not gain body mass during exercise unless the athlete started with an unavoidable deficit under medical guidance. Weight gain is an EAH warning.
• After exercise, replace about 100–150% of the mass deficit when the next session is soon (some of a large bolus is lost as urine).
• First-morning urine specific gravity and urine color plus thirst and void frequency are personal cues; spot afternoon urine after a sports drink is a poor sole marker.

Exam trap: “all athletes need 1 gallon of water a day.” A 50 kg gymnast and a 120 kg lineman in pads do not share a gallon. A gallon-plus of hypotonic fluid in a slow athlete on a cool day is how football players have died of EAH (NATA cites high-school deaths in 2014 after extreme water/sports-drink intake for cramps).

Before / during / after, practically:

• Before: pale morning urine, not chugging to the point of sloshing.
• During: fluids accessible at all times; drink to keep mass loss modest; include sodium when sessions are long or sweat is salty.
• After: food plus fluid within about 2 hours (NATA recommendation 15) to replace fluid, electrolytes, carbohydrate, and protein.

EAH (serum Na <135 mmol·L⁻¹, often symptomatic <130) comes from overdrinking hypotonic fluids—including sports drinks—and/or large sodium losses with hypotonic replacement. It is not treated with more water. Overlapping symptoms with heat illness (headache, nausea, malaise, confusion) make body-mass change and, when available, point-of-care sodium the differentiators. Puffy fingers plus weight gain plus worsening headache after a long race is EAH until proven otherwise.

---

Supplements, WADA, and NCAA Contamination Risk

The World Anti-Doping Agency (WADA) Prohibited List and NCAA banned-drug classes include stimulants, anabolic agents, and many “prohormones” that still appear in contaminated or mislabeled dietary supplements. Informed Sport, NSF Certified for Sport, and similar third-party testing programs reduce the odds of contamination; they do not make a product an AT prescription or a performance necessity. The U.S. Food and Drug Administration does not pre-approve supplement contents the way it approves drugs. NATA’s heat statement already flags thermogenic and dehydrating supplements as EHI risk. If an athlete asks “which pre-workout should I buy?”, the professional answer is food-first, third-party tested if they still choose a product, physician/dietitian involvement, and no brand endorsement.

---

Eating Disorders and REDs: Screen, Do Not Solo-Manage

Disordered eating and clinical eating disorders (anorexia nervosa, bulimia nervosa, binge-eating disorder, and other specified feeding or eating disorders) are medical and psychiatric conditions. ATs may use preparticipation questions, observe behaviors, and help administer screening tools selected by the sports-medicine team, then refer. Weigh-ins should have a clinical purpose, private setting, and no public ranking. Body-composition testing, if done at all, should follow IOC 2023 safe-assessment principles—not a coach with a spreadsheet. Return-to-play for medically unstable underfueling is a physician-led decision.

---

Sleep as Recovery and Injury-Risk Control

NATA’s 2015 heat statement recommends athletes sleep at least 7 hours per night in a cool environment because heat strain is cumulative. For adolescents, the American Academy of Sleep Medicine recommends 8–10 hours; most adults need 7–9 hours. Milewski et al. (2014, Journal of Pediatric Orthopaedics) found that adolescent athletes averaging <8 hours of sleep per night were 1.7 times more likely (95% CI 1.0–3.0) to have had an injury than those sleeping ≥8 hours. Chronic short sleep impairs reaction time, glycogen restoration, immune function, and concussion recovery. “I’ll sleep when the season ends” is an injury-risk statement, not a toughness statement. AT actions: protect travel-sleep windows, discourage all-night gaming before early lifts, treat insomnia and sleep apnea as referral issues, and do not use energy drinks as a sleep substitute.

---

Caffeine Evidence Versus Energy Drinks

ISSN and related position stands support caffeine as ergogenic at about 3–6 mg/kg (roughly 200–400 mg for many adults), taken about 30–60 minutes before exercise. Very high doses (for example ≥9 mg/kg) add side effects without consistent extra benefit. NATA 2017: mild-to-moderate caffeine (about 3 mg/kg) is not a meaningful diuretic during exercise and should not be banned on that myth alone.

Energy drinks are not the same intervention. They combine caffeine (often stacked with guarana and other stimulants) with high sugar or unregulated proprietary blends. ISSN (2023 energy-drink stand) notes that acute performance effects, when present, are largely from caffeine >200 mg or >3 mg/kg and/or carbohydrate—not from a mystery blend. Risks: excess caffeine in adolescents, sleep disruption, gastrointestinal upset, combination with alcohol, and NCAA banned stimulants hiding in “focus” products. Energy drinks are not a 6–8% sports-drink substitute during long heat practices and are not a treatment for short sleep.