NFS 2163 Second half of the semester

What factors in body water volume

body size, body composition, gender, age, intake and output

More muscle mass and lower fat is associated with

higher water content in the body compared to lower with more fat

Body water distribution

Total body water is split into extra and intracellular fluid

there is more water in the intracellular fluid

extracellular is split into plasma-in the blood and interstitial-in between cells

fluid is constantly moving from one compartment to the other due to the presence of solutes

Electrolyte distribution

concentration gradient between ECF and ICF created by anions and cations

constant pressure for sodium to leak into cells and for potassium to leak out

Sodium-potassium pump maintains gradient and prevents fluid shifts under normal conditions

How does fluid shift between compartments

Hydrostatic pressure and osmotic pressure and osmolarity

Hydrostatic pressure

pressure exerted by fluid

Osmotic pressure

“Pulling force” required of a solution to prevent a net movement of a solvent across a semi-permeable membrane, measured by osmolarity

Osmolarity

measures the total concentration of all dissolved solute particles (electrolytes, glucose, urea) within a liter of solution

Tonicity- Isotonic

Osmolarity of ECF and ICF are the same

No osmotic pressure so no net movement of fluid

No effect on cell

Tonicity- Hypertonic

osmolarity of the ECF is greater than the ICF

Osmotic pressure causes fluid to move out of the cell into the ECF

Cell shrinks

ICLICKER: When the ECF is hypotonic, which statement best describes how the osmolarity compares to the ICF?

The osmolarity of the ECF is less than the osmolarity of the ICF

ICLICKER: When the ECF becomes hypotonic, which direction would fluid movement occur?

Fluid would move from the ECF into the ICF

ICLICKER: When the ECF is hypotonic, what effect would this have on the size of the cell?

The cell would swell

Tonicity- Hypotonic

Osmolarity of the ICF is greater than the osmolarity of the ECF

Osmotic pressure moves fluid from the ECF into the ICF

Cell swells

What are sources of fluid input

beverages, food, aerobic metabolism

What are sources of fluid loss?

Sweat, respiration, urine

Insensible losses: ventilation and nonsweat diffusion

Sensible losses: feces, urine, sweat

Euhydration

achieving fluid balance, equal osmolarity, isotonic, no fluid shift, no effect on cells

Hyperhydration

greater ICF to ECF for osmolarity, hypotonic, Fluid shifts into the cell ECF→ICF, swell of the cell

Hypohydration related to dehydration

greater ECF to ICF for osmolarity, hypertonic, fluid shifts out of the cell ICF→ECF, shrink of the cell

ICLICKER: What is the primary source of sodium in the average American’s diet?

Processed foods

Sodium intake and excretion

UL for sodium is 2,300mg

Sodium is lost in urine, feces and sweat

Kidneys regulate sodium resorption and excretion

Training increases sodium reabsorption from sweat glands

Sodium concentration of an individual athletes sweat isn’t consistet

Acclimation to exercising in hot conditions results in more efficient sodium reabsorption over time

Higher sweat rates increase sodium concentration of sweat because sweat moves through the ducts faster and there is less time for sodium to be reabsorbed

Sweat testing can provide feedback about sweat rate and sweat composition

Maybe beneficial for “salty sweaters” and ultra-endurance athletes

Sodium for weight loss?

We don’t know what salt will do when it comes to weight loss and for your health

more salt=increased thirst=increased fluid intake=increased urine output

Study on Russian cosmonauts calls this into question

unexpected outcome was weight loss

subsequent study on mice found high-salt diet required 25% more Kcal

Potassium intake and excretion

Potassium intake

AI=4700mg/day

Potassium losses in sweat are typically small and inconsequential

odium is the primary electrolyte lost in sweat, with chloride being lost in similar amounts

Potassium losses are small and do not need to be replaced other than extenuating circumstances

Under normal conditions fluid balance is achieved through

consuming excess water

excreting excess water in the urine

kidneys reabsorb or excrete electrolytes as needed

ICLICKER: What causes a decrease in plasma volume at the onset of exercise?

Hydrostatic pressure

Exercise and fluid balance

exercise challenges fluid homeostasis

Hydrostatic pressure forces fluid out of the plasma at the onset of exercise Amount of loss depends on exercise intensity

ICLICKER: Which statement regarding sweat and thermoregulation is correct?

Water evaporates from the surface of the skin, thereby cooling the body

As little as 2% dehydration can impair cognitive function and physical performance

ICLICKER: When athletes lose a high volume of water through sweat, what is the impact on the tonicity of blood and muscle cells?

Blood plasma is hypertonic compared to muscle cells, causing muscle cells to shrink

Hypovolemia

loss of blood volume

Impact of hypohydration on athletic performancee

blood flow to working muscles is reduced, ability to delivery oxygen and nutrients reduced

ability to clear CO2 and waste products reduced

Decrease in VO2 max

Hypovolemia and Hyperthermia

Hyperthermia

abnormally high body temperature

ICLICKER: What determines how much we sweat?

How hot it is, intensity of exercise, amount of hydration you have yourself, illness, humidity

Regular exercise trains the body’s thermoregulation system

Water vapor in the air impedes sweat from evaporating from skin

Degree of acclimation, exercise intensity, environmental temperature, clothing/equipment

If you are well trained, then you are more likely to sweat more because your body is used to it

ICLICKER: What is the most common cause of exercise-associated muscle cramping (EAMC)?

Dehydration

Electrolyte imbalance

None of the above

None of the above

these differ from heat cramps

cause is not fully understood, but most likely due to muscle fatigue/overload

Heat cramps

Total body cramping when exercising in the heat is associated with losses of fluid and sodium

Assessing hydration status

Tracking pre and post exercise weights is more accurate

1 L of water lost = ~1kg (2.2lbs)

Not recommended for people with disordered eating

Thirst is a better indicator of hydration status than urine color, immediate alert for water need

Hypothalamus monitors blood volume and sodium osmolarity

Urine color is affected by factors other than fluid intake, reflects longer-term fluid balance

Daily hydration assessment

every morning athletes assess their thirst, urine color, body weight compared to previous morning

Pre-gaming sodium before an event

multi-day loading leads to 95%+ of sodium being excreted

Goal prior to exercise is to be adequately hydrated and consume carbohydrate if appropriate

~5-10mL/Kg 2-4 hrs before

ICLICKER: According to the American College of Sports Medicine, what is the recommendation for fluid intake during exercise?

Develop and individualized hydration plan that factors in sweat rate

Replacing more than 70% of fluid losses can result in hyponatremia

Sweat rates vary widely (~0.5-2.0L/hr), so athletes should adjust intake based on their own sweat loss

Individualized plan for hydration

Availability/access

Sweat rate and composition of sweat

Duration of exercise

Exercise intensity

Clothing and environmental conditions

Potential risk of Hypponatremmia

Hyponatremia

abnormally low concentration of sodium in the blood

Consuming excess water can result in coma or death

high sweat rate combined with high water intake causes fluid shift from ECF to ICF

Brain cells swell leading to neurological symptoms, seizures, coma and even death

Studies show endurance athletes are more likely to be

overhydrated than to be dehydrated

Hydration replenishment after training

Restore lost body water to achieve euhydration

Replace sodium and other electrolytes lost

Incorporate carbohydrate and protein for recovery when appropriate

General guidelines: 1.5L/Kg of body weight loss

Sports drink tonicity

Hypertonic, ideal for replenishment after exercise, not recommended for consumption during exercise because higher tonicity can cause digestive issues

Isotonic, ideal for hydration during endurance exercise

Hypotonic, ideal for rapid hydration/rehydration, not ideal for providing energy during exercise or replenishing glycogen after

Caffeine induced diuresis is

small

females are more susceptible to effects

exercise negates any diuretic effect

Coconut water

studies show it is no more hydrating than water

potassium and sodium content make it an inferior choice to sports drinks

Sports drinks aren’t necessary for all workouts

water is sufficient for most workouts lasting <90 minutes

Micronutrients and health

needed in small amounts, essential nutrients, both play critical roles in the body

Vitamins

organic susceptible to heat, air and acid

Minerals

inorganic, resilient to heat, air and acid

ICLICKER: Vitamin toxicities are most likely to occur with

Fat soluble vitamins

Water soluble vitamins

found in the watery portions of foods, cannot be stored in the body, CB

Fat soluble vitamins

require fat to be absorbed, stored in the liver and fat tissue, ADEK

Functionality of vitamins

energy metabolism, red blood cell formation, antioxidants, growth and developments

How much do we need of vitamins

RDA or AI- may differ based on gender and age

Tolerable Upper Intake Level (UL)- only established for 8 vitamins

The average American diet and vitamins

energy intake and nutrient density play major roles in who falls short

Athletes who consume inadequate calories are at an increased risk for deficiencies

D and E come up short the most

ICLICKER: At what point will and individual exhibit medical symptoms of a deficiency

When there is a clinical deficiency with general symptoms like fatigue and gastrointestinal distress

Clinical deficiencies were common until the mid-1900s

Fortification and enrichment

Athletes may have mild or subclinical deficiencies that impair performance

Can’t I just get tested for a deficiency

Blood levels are not indicative of storage or functionality

Testing metabolites is possible for some vitamins

A dietary assessment to determine average daily intake is the most accurate method

Too much vitamins

toxicities take months or years to develop, non-specific medical signs and symptoms, toxicities in the US are rare, mega-dosing with vitamin supplements is most common cause of toxicity

ICLICKER: Which vitamins increase energy levels

Fat soluble

B

C

None of the above

None of the above

Because there is no calories in vitamins then there is technically no energy coming from them, if the body already has enough through a normal diet then the supplement will not impact energy levels if they take a supplement

Antioxidants and free radicals

Free radical= molecules with one or more unpaired electron

Reactive oxygen species (ROS)= subset of free radicals

When exercising we release free radicals

Balance between production of ROS and clearance is key

Antioxidant systems rely on vitamins to neutralize ROS

ICLICKER: Which is a potential result of athletes mega-dosing with antioxidant supplements?

Impaired adaptation to training

Training enhances body’s antioxidant defense systems

Antioxidants at high doses impair adaptations to training and may act as pro-oxidants

Macrominerals

Microminerals

How much is enough of minerals

RDA or AI, established for 15-21 minerals, amount varies greatly but all are important, UL established for 16 minerals

Do athletes need more minerals

Factors that could increase need, Decreased absorption from GI tract, Increased loss in sweat or urine, Increased utilization due to the stress of exercise, Increased need associated with large muscle gains and maintenance, Effect of exercise is small, a healthy diet should meet needs

Americans tend to be deficient in calcium and magnesium

ICLICKER: How does the body respond when stores of a particular mineral become too low

By increasing absorption of that mineral

Mineral absorption and excretion is well regulated

In general mineral absorption is low to moderate, excretion is low

Homeostasis is maintained by adjusting absorption and excretion

If storage is high, absorption decreases and excretion increases

If storage is low, absorption increases and excretion decreases

Certain minerals compete for absorption

Excessive intake of one mineral may result in the deficiency of another

Anti-nutrients

chemically active substances in plant foods reducing their availability

Bind to nutrients thereby preventing their digestion and utilization by the body

Phytic acid, oxalate, insoluble fiber

ICLICKER: How does insoluble fiber act as an anti-nutrient

Faster transit time of food in the digestive tract

Bone health and minerals

Peak bone mass- PBM greatest amount of bone an individual can attain

Reached in late teens to early 20s

Bone is dynamic tissue going through the processes of growth, modeling, and remodeling

two primary concerns for athletes- stress fractures, and osteopenia/osteoporosis

ICLICKER: What is the biggest determinant of an individual peak bone mass

Genetics 60%

body weight, type of sport/training, energy availability, protein intake, vitamin d intake, calcium intake, loss of sodium and calcium in sweat, and hormones are the rest of it

ICLICKER: What is a health or performance consequence of a clinical iron deficiency

Reduction in VO2 max and decrease in endurance capacity

Erythrocytes

red blood cells transport O2 and CO2

Hemoglobin and myoglobin are

critical for O2 transport and storage

Effects of subclinical iron deficiency

aren’t known

Clinical deficiency of iron

VO2 max decreases 10-50% and endurance capacity is reduced

Diets low in heme iron

increase risk of deficiency

Should athletes use mineral supplements

If you eat a balanced diet then no, unless you have dietary restrictions then talk to your doctor about supplementation

Steps in diet planning

assessment, goal setting, action plan, evaluation and reassessment

Dietary assessment

Age, height, weight, gender, body composition (if available), RMR

Food recall (3-7 days), avg: energy intake, macro and micronutrient intake, and fluid intake (brand, portion size)

Type of activity, duration, frequency, intensity, based on current training cycle

Food allergies/intolerances, dietary restrictions, food likes/dislikes, food access, culinary abilities, food budget, medications/supplements

Goal setting

At least one goal in each area: athletic performance, weight and body composition, health

Action plan (dietary prescription)

individualized meal plan with an appropriate amount of calories, carbs, protein and fat

Calculations based on biometrics and information obtained in the interview

Proper amount, timing and distribution across the day of protein, carbs and fat

Emphasis on nutrient-dense foods

Supplement recommendations if appropriate

Factors in food preferences, budget, dining habits, etc

Evaluation and reassessment

Are goals being met?

Are calorie and macronutrient goals still appropriate?

Consider training periodization

Nutrition periodization = the creation of a nutrition plan to support training that has been divided into distinct periods of time

just recommendations based on mesocycle

ICLICKER: How are athlete’s macronutrient needs most accurately determined?

Using grams per kilogram of body weight

ICLICKER: The number of calories needed to maintain energy balance after the macronutrient recommendation are met is known as

Discretionary calories

Caffeine

CNS stimulant, blocks adenosine which blocks what makes you sleepy, releases calcium into muscles, muscle strength more impacted, 2+ reps on average for bench press, sleep disruptions, higher HR, major complications at 1200mg, 400mg symptoms, marketed to youth, differing amounts of caffeine in different bevs

Cannabidiol (CBD)

hemp cannabis (not THC), indirect effects like helping with sleep and pain tolerance, in drops foods and ointment, relieve stress, legal, higher doses may contain THC which is illegal, don’t buy under the table, could show up on drug tests if it contains trace amounts of THC

Platelet rich plasma therapy

patients own blood, injected into injury site, 1-3 injections, meant to accelerate healing, experimental, expensive, can vary in efficiency, no big safety concerns, discomfort pain or bruising, gray area: not regulated by a committee

Tart cherries

organic, recovery through muscle soreness, sleep, inflammation, free radicals neutralized with antioxidants, endurance, long distance, polyphenols: help produce antioxidants, blocks inflammation pathways, have natural melatonin, tryptophan= building blocks of melatonin, blocks muscle adaptation if too much, great around big events, gummies powder juice, periodization week to 5 days before, not much research, no major safety issues, can have similar effect as NSAIDs, tummy problems

Beet root

root vegetable, antioxidants, folate, potassium, vitamin C, high vasodilation properties, cardiac endurance, increased muscle contraction, mitochondrial efficiency improved, 1.5-2.5 hrs before activity, good for endurance vs short distance, moderate athletes will have more impact than advanced athletes, some risk of nitrate problems

Beta alanine

Amino acid your body makes, meat, stored in muscles, delays muscle burn, mid distance, small performance benefit, temporary tingly feeling on skin, low risk of problems

Sodium bicarbonate

baking soda, hydrogels during activity carb mix, body already makes it as a buffer for H ions, no benefit for short seconds to 8 min, no evidence for endurance athletes, GI distress, possibly can gut train for it, safety? Salt goes over sodium UL and could lead to problems like seizures, bad/banned for horses

Coconut water

young green coconuts, potassium (most prevalent), sodium, calcium, replace electrolytes, hydrates same as water, does worse than other sports drinks, 2oz for fluid of 1lb of loss, rehydration, low in sugar, high potassium (bad for people with kidney problems), good for taste, lyte hydration, no sports benefits, child labor, deforestation, plastic problems

Blood doping

high blood cell count, endurance athletes, inject themselves with hormone, inject more O2 efficient blood, blood cells live longer an prevent apoptosis, transfusion but more population in injections, UNSAFE with infection or heart attack, banned by Olympic Committee, hard to detect in small amounts, used to help increase VO2 max, very effective for endurance athletes but it is unfair

Ketones

compound developed by liver with lack of carbs, back up fuel for muscles and brain, ketogenic diet breaks down fat, increased cognitive focus, performance (endurance), uses fat already in body, inconclusive findings, not ton of information on supplementation, dependent on individual

Gatorade

Sports drink, enhances hydration, maintains blood volume, energy because of carbs, improve endurance, mental focus, better for long endurance, glucose/sucrose mix, 60+min exercise, not legal concern, marketing for all activities not just endurance, some stomach problems

Creatine

naturally occurring in skeletal and cardiac muscle, meat and fish, high intensity exercise like powerlifting, loading and maintenance phases, stay hydrated, PCr stores phosphates for when ADP needs another to make ATP, generally safe, rare events linked to excessive consumption or dehydration, good for recovery and rigorous training

What are seven macrominerals

calcium, phosphorus, magnesium, sodium, potassium, chloride, sulfur