Exercise and Environments and body composition

2 ways to think about environment

altitude and temperature

Altitude means…

“thin air”: lower gas density, lower oxygen with each breath

Hyperventilation is…

immediate: high breath rate, high O2 delivery, high CO2 removal and acid-base balance changes

Hyperventilation can result in…

acute mountain sickness: headache and brain and lung swelling

Altitude body changes…

higher heart rate, higher O2 carrying capacity to create more RBCs and Hb per RBC

____% of energy is released as heat during exercise

80%

calorie definition

a unit of energy equivalent to the heat energy needed to raise the temperature of 1 gram of water by 1 °C

Exercise in the heat body effects sweat …

sweat evaporates off you and removes body heat, high humidity in the body and hyperthermia happens if sweat cant evaporate

Exercise in the heat body effects heart rate…

higher heart rate, more skin blood flow(higher peripheral vasodilation and heat dissipation), less muscle blood flow

Exercise in the heat body effects stroke volume…

lower stroke volume, high fluid loss, low blood volume, urine test used to determine these levels (fluid replenishment is vital)

Exercise in the cold effects on core temperature

Hypothermia lowers core body temperature, body shivers to move muscles to produce more heat

Exercise in the cold effects on peripheral vasoconstriction

low skin blood flow and heat dissipation, need to layer and hold sweat in to keep warmth and increase bodys metabolic rate, and increase blood flow to extremities

Types of body composition measurments…

1. BMI

2. hip to waist ratio

3. skinfold measurments

4. BIA (bioelectrical impedence analysis)

5. ultrasound

6. air displacement (bodpod)

7. hydrostatic underwater weighing

8. Dual Energy X ray absorbtiometry (DEXA/DXA)

BMI strengths

easy to calculate, strong correlation to health outcome

BMI weaknesses

not strongly coordinated to body fat, population specificity

hip to waist ratio strengths

easy to calculate, good for risk assessment

hip to waist weakness

doesnt give a lot of information

skinfold testing strengths

non invasive, fast, inexpensive

skinfold testing weaknesses

error is based on tester experience, not accurate for very obese people or very lean people, considers of surface fat not visceral fat

BIA strengths

relatively inexpensive, portable, home use,

BIA weaknesses

hydration effects results, prediction based on prediction, 8-12% margin of error for outliers

Ultrasound strengths

portable, relatively inexpensive, potentially very accurate

ultrasound weaknesses

accuracy depends on algorithm, potential user error, gel (messy)

Bod Pod strengths

very accurate, easy to use, non-invase

Bod pod weaknesses

claustrophobia, specialized equipment, requires privacy

underwater weighing strengths

very accurate, considered a long time standard

underwater weighing weaknesses

uncomfy, needs privacy, messy

DEXA/DXA strengths

precise, provides localized data, also scans bone density

DEXA/DXA weaknesses

expensive, uncommon, specialized equipment