chapter 14: sports nutrition - nutrition

substrate reliance

trained individuals are more efficient in using certain substrates

rely on fat: long distance and marathon runners

• need more glycogen stores and dig into fatty acid stores, takes longer to convert to ATP

• speed and intensity have to come down to meet

split bt carb and fat: soccer, tennis, intensity fluctuates

• body changes type of substrate fueling activities

rely on carb: short spurts of high intensity, spriints

• anaerobic glycolysis

inactivity risks

CVD, cancer, stroke, type 2, HTN

• heart works less hard with more mitochondria and efficient O2 delivery for less strain on CV, lower resting HR

• CVD: arteries hardening, reduce HDL

• cancer: inflammatory markers

• type 2: lack of PA causes less response to insulin, not enough glucose uptake, higher blood sugar levels

• HTN: blood vessels restricted instead of dilated

• slower metabolism: makes it harder to regulate blood sugar and breakdown fat

substrate utilization

breakdown of fat, protein, and carbs for fuel and how it influence show long you can exercise

• fat and protein: paleo, keto diets

  • people can train their bodies to adapt to intake

  • fat and protein heavy diet does NOT help you exercise for long periods — no carbs for ready glycogen to push past exertion and exhaustion

• glycogen: more carbs = stored in liver and muscles

  • high carb diet maxes stores, amt stored depends on diet

body uses glycogen UNTIL sustained aerobic activity that uses some fat

• regardless, run out of glycogen at 2-3 hrs

• endurance athletes with full carb diet reaches full hours, and can use more fat for fuel to spare limited glycogen and sustain high intensity

avoid glucose depletion

high carb diet with 45-65% of calories

• 70% in endurance athletes, allow room for other macronutrients

• consume during prolonged exercise: gatorade, powerade, gel packs

  • right amt of carb and electrolytes to replenish nutrients lost

  • quick carbs

• carb rich foods after activity: couple hour window for athletes to replenish glycogen stores

  • ex: choco milk — dairy and protein, natural sources

fat

intake recommendations: 20-35% and less than 10% from saturated

• athletes benefits are same as general population: also need insulation, maintain internal body temp, and reproductive health

• low int, aerobic training: high carbs

• does NOT run out like carbs

• factors: duration, intensity, training

  • trained: uses fat as fuel source at high intensity to spare limited glycogen

protein

endurance athletes use more ____ as fuel (10% of total fuel during activity and rest)

• diet requires adequate energy and carbs to spare protein

• higher intensity and duration: higher protein and carb needs

  • supplements not necessary: can meet thru diet

• RDA for adults: 0.8 g per kg body weight (someone that doesn’t exercise)

  • recreational: 1.0

  • marathon: 1.2-1.4

  • strength: 2.0

iron deficiency

prevalent along young active women and main symptom is fatigue

• anemia: low iron or Hb that impairs O2 transport

• sports anemia: increased PV, low RBC to catch up and low O2 delivery

• vegetarian athletes: no heme iron in diet

• active teens have higher iron needs: rapid muscle and blood growth, period blood loss in girls, high intensity exercse

hydration

hydrate before activity, during, and after activity — balance of water and electrolytes

• drink extra fluid days before an event

• fluids for everyday, active people: plain water

• fluids for endurance athletes: CHO containing bevs

  • sodium is lost with sweat — humidity and duration of activity (higher losses in untrained)

• regular food and drinks usually work, sports drink for long workouts

• salt tablets worsen dehydration: pull water into gut instead of bloodstream

hypoatremia

drinking too much water without replacing sodium and dilutes blood sodium levels

• endurance athletes at risk (marathon, long events)

• people who: overdrink water, sweat a lot, replace fluids but not electrolytes

• sports drinks: fluid, glucose, sodium — markets audience drink more but Na makes you more thirsty

monitoring

hydration: check body mass before and after exercise

• loss = fluid lost thru sweat

• 1 kg body mass = 1 L fluid lost, and replace fluid after

nutrient density: foods that give vitamins, minerals, and calories that supports recovery and performance

• fruits, veggies, whole grains, lean protein

CHO is main fuel: eat carbs before activity to fill glycogen stores, easy to digest

• need more CHO as intensity and duration increases to delay fatigue

protein: needed after training for muscle repair and adaptation to training

female athlete triad

energy imbalance of calories in and out to balance exercise expenditure

1) disrupted eating: with or without an eating disorder

2) amenorrhea: no longer producing female reproductive hormone at an affective level, menstrual dysfunction

3) loss of bone density: mimics osteoporosis

• can go without estrogen/long term implications and cannot be fully reversible once it happens

• causes: low energy availability

• symptoms: fatigue, absent menstrual cycles, recurring stress

• risks: most common in sports focusing on aesthetics or weight (ex: gymnasts)

red s

relative energy deficiency in sport, formerly known as the female athlete triad

• athlete doesn’t consume enough calories to support their energy expenditure

• results in poor health and declining performance, impacts athletes at all levels

1) decreased performance: insufficient energy available

2) hormonal disruptions: affects metabolism and recovery

3) impaired bone health: risk of stress fractures

4) weakened immune health: frequent illness

5) reduced muscle strength and endurance

6) psych impacts: fatigue and mood changes