SEHS Option A.2 - Environmental Factors and Physical Performance

Factors that affect the metabolic rate

Physical activity, food, age, gender, environment temperature

The three major sources of heat in the body are...

Cellular respiration, muscular activity, ingestion of food

Anabolism

Associated with growth, making and creating bonds

Catabolism

Release of energy, producing energy by breaking bonds

Explain the relationship between cellular metabolism and heat during rest and exercise

Humans need energy to produce heat in order to maintain the core temperature // humans need energy to perform mechanical work like exercise // the body uses oxygen and food to make energy // ATP can be converted into other forms of energy // during exercise, the net ATP production increases // about 60 to 70% of energy is turned into heat // as metabolism increases, more heat is produced // The heat production will be at a constant rate if at rest within a stable thermoneutral environment

The normal physiological range for core body temperature is...

37°C +/- .6°C

Thermoregulation

The ability of an organism to keep its body temperature within certain boundaries, despite differences in the surrounding temperature

Conduction

Involves skin contact with an object of a different temperature. And example is an ice pack.

Radiation

The transfer of heat from a hotter to cooler object via infrared waves

Convection

Moving heat from one place to another by the movement of water or air

Ways to gain heat

Basic metabolic processes, shivering, exercise, metabolic activity, radiation and conduction to the body

Ways to lose heat

If evaporation/sweating, convection, radiation and conduction from the body

Sweat: its formation the sweat response

This is the primary avenue for heat dissipation during exercise, about 80% of total heat loss during activity // when ambient temperature exceeds body temperature, sweat readily evaporates from the skin // sweating begins within several seconds of the start of exercise and will eventually reach equilibrium in direct relation to the exercise load // The amount of surface exposed to the environment, the temperature, and the humidity all affect the amount of sweat vaporized from the skin // sweat must evaporate to cool the body // as the core body temperature increases, sweat production increases

What are the physiological responses that occur during prolonged exercise in the heat

Cardiovascular drift (the heart rate drifting upwards because body fluids are lost, the stroke volume is lowered and the body needs to maintain the normal cardiac output), sweating, use of glycogen, vasodilation, reduced blood flow to muscles, death, increase in court temperature, reduced sweating response over time, less blood circulation

How to treat health risks from the heat

Cease exercise, go to cooler environment, get medical attention, rehydrate, monitor cord temperature, immersion in cold water or ice, remove heavy clothing, put feet up, ICE armpits and groin

How to prevent health risks from the heat

Careful planning, awareness of symptoms, being acclimatized, wearing an ice fest, exercising at lower temperatures, wearing proper clothing, avoiding direct sunlight, adopting the work out, running through showers, making sure you are hydrated

How to acclimatize to heat

Take 10 to 14 days training in similar environmental conditions, increase the intensity of training gradually

On the day of competition (in hot weather)...

Wear light colored clothing and a hat, adapt the warm-up, wear an ice vest, take an ice bath

Physiological adaptations that occur with heat acclimatization

Increased plasma volume, increased salt retention, reduced heart rate, more blood goes to skeletal muscles, muscles use less glycogen, start sweating earlier, decreased resting core temperature

Heat tolerance depends on...

Acclimatization, fitness, body mass, water, age

Outlined the mechanisms that the body uses to maintain core body temperature in cold environments

Shivering, nonshivering thermogenesis, peripheral vasoconstriction

Shivering

The metabolism is increased and skeletal muscles because they have been contracting and expanding quickly, this is triggered to maintain homeostasis in the body

Non-shivering thermogenesis

Increases the cellular metabolism rate and thereby increases heat production

Peripheral vasoconstriction

Shunting blood towards the core, rather than extremities

Heat cramps

Least severe, warning for more serious emergency, signals body is struggling. Caused by loss of salt and water from sweating

Heat exhaustion

When one has an elevated core body temperature, but is lower than 104°F or 40°C

Heatstroke

When high court temperature is over 40°C

Hyperthermia

When the core body temperature is too high, and the body produces more heat than I can dissipate

Surface area to volume ratio

A large surface area to volume ratio increases heat lost

Ideal surface area to body mass ratio's with environments

Being larger and rounder is beneficial in a cold climate, while being lean is better in a hot climate

Wind chill

A chill factor created by the increase of rate of heat loss via convection and conduction as caused by wind

Factors that affect windchill on a person

Age, health, wind speed, athletes bead, surface area to volume ratio, clothing

Dangers of wind chill

The temperature is only an estimate, you could be exposed to a lower core temperature, frostbite, hypothermia, death

Physiological responses to exercise in the cold

Vascular shunting, decrease in muscle function, less blood goes to the muscles, muscles become weaker, fatigue sooner and affect performance, body processes slow down, shivering responses greatened, we heart rate is lowered and the cardiac output is decreased

What are they health risks of exercising in the cold, including Coldwater

Frostbite, hypothermia, death

Discuss the precautions that should be taken when exercising in the cold

Clothing, rehydration