Environmental Factors and Other Issues with Exercise

Question 1

Core body temperature

Answer 1

Core body temperature ranges between 97°F and 100° F

Core body temperatures are generally lowest during sleep and highest during exercise or with exposure to hot environments

Question 2

The ___ in the brain is the coordinating center for temperature regulation and acts much like an internal thermostat

Answer 2

preoptic/anterior hypothalamus (POAH)

Question 3

preoptic/anterior hypothalamus (POAH)

Answer 3

initiates responses to reduce increases in core body temperature

When it perceives heat, it strives to increase heat loss through peripheral vasodilation of blood vessels, which redistributes blood carrying heat toward the periphery

When it perceives cold, it strives to decrease heat loss through peripheral vasoconstriction of blood vessels, which redistributes blood toward the core

Question 4

Core temperature tolerance ranges.

Answer 4

limits of survival: 73.5-80.5 F

cold exposure: 80.5-97 F

normal range: 97-100 F

heat exposure: 100-105.8 F

heat stroke: 105.8-111 F

limits of survival: 111-115

Question 5

Factors Affecting Heat Gain

Answer 5

Resting metabolism (RMR)

Muscle activity

Hormones and nervous activity

Thermic effect of food

Non-exercise thermogenesis (NEAT) anything not sleeping, sports or exercise related

Warm environments

Question 6

The body’s thermoregulatory mechanisms that primarily protect against overheating at rest and during exercise:

Answer 6

conduction
evaporation
convection
radiation

All but evaporation are considered “dry Heat exchange”

resistance to dry heat exchange is called “insulation”

Question 7

conduction

Answer 7

The exchange or transfer of heat from warmer objects to cooler objects via direct molecular contact

Its contribution to heat dissipation during land-based exercise is very small

Its contribution to heat removal when the body is immersed in water is significant

Question 8

conduction depends on the following variables:

Answer 8

The thermal gradient (i.e., the temperature difference between the two surfaces)

The thermal properties of the two surfaces, objects, or mediums in contact

Question 9

evaporation

Answer 9

transfer of heat when a liquid changes physical states by becoming gas, a process that requires energy to vaporize the liquid

ex) sweat evaporating off skin

As the vapor (gas) leaves the skin surface, so will the heat.
> Sweat must evaporate in order for heat to leave the body

Question 10

The effectiveness of sweat evaporation from the skin depends on:

Answer 10

> Temperature gradient - when it is hot out, gradient is small so efficiency is reduced, and you need to sweat to thermoregulate

> Relative humidity of the surrounding air

> The amount of skin surface area exposed to the environment to facilitate sweat removal from the body

> Convective air currents that lift the vapor into the surrounding air

Not all sweat is lost to the environment

> Sweat that drips off the body does not contribute to cooling but does contribute to fluid losses and dehydration

Question 11

high humidity =

Answer 11

air cannot readily accept more water vapor

Question 12

convection

Answer 12

Its contribution to heat removal when the body is immersed in water is significant

Convection contributes more significantly to heat loss during land-based exercises performed on breezy or windy days

Question 13

Heat removal dependent on the movement between the 2 surfaces and the thermal gradient:

Answer 13

Greater movement and larger thermal gradients exchange heat more rapidly

Ex: air current from a fan will remove more warm air from the skin surface

Treading water lightly facilitates rapid heat loss given the thermal properties of water, while active swimming generates adequate metabolic heat to offset this convective heat loss

Question 14

radiation

Answer 14

involves the passage of electromagnetic heat waves moving along a temperature gradient from a warm or hot object into a cooler object

Ex. the sun’s rays warming the Earth at sunrise, or heat coming off tar streets in summer

Question 15

The human body constantly radiates heat through skin into the surrounding cooler environment and any objects surrounding the body, while simultaneously ____

Answer 15

receiving heat from warmer objects surrounding it

Question 16

Sweat and energy expenditure

Answer 16

A calorie: a unit of energy…

the energy needed to raise the temperature of 1 kilogram of water through 1 °C is equal to one thousand small calories and often used to measure the energy value of foods

For each liter of sweat lost, the body removes approximately 580 kcal (kilocalorie) (2,428 kJ) of heat

Question 17

Excretion

Answer 17

involves the loss of heat via any materials excreted from the body

• gaseous (air exhalation)
• liquid (urine)
• solid (feces)

accounts for significant fluid removal from the body considering daily urine output, fluid volume contained in feces, and the estimated additional 300 mL of fluid lost through the mucous membranes of the respiratory passages

Women lose heat quicker than men in cold temperatures

Question 18

Evaporation depends on the availability of fluid within the body, so ____

Answer 18

fluid lost to excretion may influence sweat rates

Question 19

Factors That Influence Thermoregulation

Answer 19

Gender
Age
Body size and composition
Conditioning level
Hydration status
Clothing
Environmental factors

Question 20

Gender =

Answer 20

> females less lean mass, less body water, have larger surface area/body mass ratios (more fat mass, less lean ms mass) favoring dry heat exchange vs sweating, and lose heat quicker than men in cold temps

> women have more % body fat, and can tolerate mild cold exposure better than men

Question 21

Age =

Answer 21

> children sweat at lower rates because of smaller quantities of body water

Question 22

Older adults are also more susceptible to the hot and cold stress =

Answer 22

> Dehydration (bc of a diminished sense of thirst)

> Loss of subcutaneous fat tissue to insulate

> Loss of muscle tissue to generate heat

> Potential cognitive losses associated with aging

> Changes within the skin layer

> Reduced thermoregulatory efficiency

> Medication usage that can affect hydration status

Question 23

Body size and composition

Answer 23

> Muscle tissue capable of generating heat

> Both muscle mass and body fat offer insulation

> Larger surface areas dissipate heat quicker

> Less muscle generates less heat

Question 24

Conditioning level

Answer 24

With increased fitness: Increased blood volume, improved circulation of blood to skin/periphery during exercise, increased sweat rates, reduced core temperature threshold to initiate sweating

Question 25

Thermoregulation in Hot Environments

Answer 25

Warmer skin surface temperatures are detected by the peripheral receptors that stimulate both the POAH and cerebral cortex

Question 26

Increases in blood temperature are identified by central receptors that activate sympathetic nervous system (SNS) responses from the POAH

Answer 26

The POAH stimulates an SNS response to the smooth muscles that encircle the surface arterioles to vasodilate and bring more blood (which is carrying heat) to the skin’s surface The POAH stimulates an SNS response to initiate sweat production

Question 27

During exercise in warmer environments, two competing cardiovascular demands exist:

Answer 27

Need for oxygen/nutrient delivery to the exercising muscles Need for peripheral blood flow to the skin to remove heat

Question 28

The increased demand for cardiac output is met by:

Answer 28

increasing heart rate and heart contractility to ensure appropriate circulation to these two regions redistributing blood away from nonessential organs and systems SNS initiates vasoconstriction in nonessential organs and vasodilation of vessels in the exercising muscles and near the skin surface

Question 29

Eventually, the demands of exercise and thermoregulation will exceed the cardiovascular system’s ability to meet these demands- and blood delivery goes to exercising muscles…...

Answer 29

The body becomes unable to regulate against a rising core temperature When core temperatures rise to 104°F and 105.8°F (40°C and 41°C), it usually signals the brain to begin to cease exercise Increases in core temperature elevate circulating levels of epinephrine, which enhances glycogen utilization, contributing to lactate build up, exhaustion and fatigue

Question 30

Circulatory blood flow to muscle tissue takes precedence over temperature regulation

Answer 30

making the environment a key influence on the likelihood of developing heat-related illnesses The body’s ability to remove heat is not influenced by air temperature alone humidity, air currents, and thermal radiation all contribute to heat stress and heat removal from the body

Question 31

Exertional Heat Stroke

Answer 31

can affect athletes during high-intensity/long-duration exercise and results in activity withdrawal/collapse during or following activity exercise-associated muscle cramping, heat exhaustion, or Exertional Heatstroke (EHS) Although some are more prone to heat illness, EHS can affect all athletes, even in relatively cool environments

Question 32

The National Athletic Trainer’s Association (NATA) released a statement:

Answer 32

NATA diagnoses EHS as a core temp. greater than 104°F to 105°F accompanied by central nervous system dysfunction (e.g., disorientation, confusion, dizziness, loss of consciousness, collapse) Treatment must reduce the core temperature to no less than 102°F as soon as possible to limit risk of morbidity and mortality Treatment should advocate cold-water immersion

Question 33

Adaptations to Heat Stress

Answer 33

The process of acclimation to hot environments normally occurs within 9 to 14 days, although well-conditioned individuals usually require less time to acclimate To optimize one’s ability to acclimate to hot environments, individuals should reduce their normal training volume and intensity initially, training at intensities below 70% V̇O2max for durations lasting between 20 and 60 minutes

Question 34

With appropriate exposure to hot environments, the cardiovascular system will undergo several important adaptations:

Answer 34

> A progressive expansion of blood volume, increasing over the first 10 days > More effective cardiac output and blood distribution to the skin > Improved cutaneous blood flow within the peripheral regions

Question 35

With appropriate exposure to hot environments, the thermoregulatory system will undergo several important adaptations:

Answer 35

> Increased sweat rates to remove more heat > Decreased sweat thresholds (i.e., the temperature at which sweating initiates) > More effective distribution of sweat over the surface of the skin > Decreased electrolyte concentrations in sweat, given improved efficiency in reabsorbing these electrolytes from sweat

Question 36

Dehydration

Answer 36

The sensation of thirst in adults younger than 50 years is generally initiated at about 1% dehydration or loss of body weight At 2% dehydration, performance is compromised Performance diminishes and symptoms become more severe with increased levels of dehydration until around 8% loss of body weight when the risk for development of severe heat illnesses (exertional heat stroke) becomes significant

Question 37

Hydration During Exercise General guidelines:

Answer 37

Consume 7–10 ounces every 10 to 20 minutes Ideal fluid temperatures exist between 50°F– 59°F Sport drinks should not contain carbohydrate concentrations greater than 8%

Question 38

Post-Exercise Rehydration

Answer 38

This includes consuming water to restore hydration, carbohydrates to replenish glycogen stores, and electrolytes to speed rehydration 12 hours to recover—usual meals, snacks, and plain water General guidelines: > Drink up to 1.5 L of fluid for each kilogram of body weight lost

Question 39

Electrolyte imbalance

Answer 39

sodium concentration in serum (liquid part of blood without the clotting agents) is lower than normal (less than 135 milliEquivalents/L)

Question 40

Hyponatremia

Answer 40

Can occur as a result of excess body water diluting serum sodium (i.e., over hydration), although the condition can be caused by excessive loss of sodium because of vomiting, diarrhea, or even sweating result of a combination of losing excess sodium and overhydrating, and may sometimes occur during exercise when one rehydrates with water but fails to replace lost electrolytes

Question 41

Fundamentals of Exercise Physiology and Nutrition

Answer 41

It’s important to consume the right foods and drinks in the right combinations and quantities

Question 42

Strategic ingestion can positively impact performance:

Answer 42

Specific timing of nutrient and fluid intake Composition of both nutrients and fluids Quantities ingested

Question 43

The Role of Macronutrients in Exercise Performance

Answer 43

Fat = Energy source during exercise at lower intensities Carbohydrates = Quick energy source, especially when exercising at higher intensities Protein = Helps build and repair muscle An ideal eating plan will contain the right mix of foods and drinks to ensure adequate carbohydrates, protein, fat, and micronutrients to support the specific exercise demands on the body

Question 44

Fat loading

Answer 44

Goal is to slow glycogen depletion May be ill-advised for some athletes, as it may lead to general feelings of fullness, lethargy, and fatigue Studies show no consistent benefits Long-term exposure to high-fat and low carbohydrate diets may help the body adapt and increase fat utilization

Question 45

Carbohydrates

Answer 45

benefit exercise as fuel for muscle activity Availability is important for endurance performance, especially during high-intensity exercise or when individuals are glycogen depleted Serious endurance athletes may need to practice carbohydrate loading

Question 46

Protein

Answer 46

plays an important role in both endurance and muscle-strengthening exercise Both modes of exercise stimulate muscle protein synthesis, which is further enhanced with consumption of protein around the time of exercise helps to preserve lean muscle mass and assure that weight lost comes from fat rather than lean tissue

Question 47

Sports nutrition strategies should address three exercise stages:

Answer 47

- Pre-exercise - Exercise - Post-exercise

Question 48

Pre-Exercise Fueling

Answer 48

Typically describes the 4 hours before exercise Carbohydrates - Pre-exercise meal: aim to consume 2 to 4 g/kg of body weight (0.91–1.8 g/lb) - Pre-exercise snack: aim to consume 1 to 1.5 g/kg of body weight. Carbohydrate loading for events lasting longer than 90 minutes may be beneficial Protein - (endurance athletes) Recommended intakes between 1.2 to 1.7 g/kg of body weight

Question 49

Fueling During Exercise

Answer 49

0-60 minutes: replace water only, as electrolyte losses via sweat and muscle glycogen depletion are minimal, unless exercising in extreme environments or participating in vigorous exercise 60-90 minutes: replace water and electrolytes lost via sweat, giving consideration to carbohydrate refueling 90-120+ minutes: replace water and electrolytes lost via sweat, plus carbohydrates depleted from storage

Question 50

Post-Exercise Refueling

Answer 50

The average client does not need any aggressive post-exercise replenishment Clients following vigorous training regimens benefit from strategic refueling Best post-workout meals include mostly carbohydrates accompanied by some protein Consumption of protein immediately post-exercise helps in the repair and synthesis of muscle proteins Refueling should begin within 30 minutes of a workout High-carbohydrates meals within 2 hours

Question 51

Athletes and Eating Disorders

Answer 51

A number of athletes take healthful habits to an extreme, and their behaviors become pathologic and detrimental to their overall health and well- being Eating disorder—a severe alteration in eating patterns linked to psychological or emotional changes

Question 52

Anorexia Nervosa Formal Diagnosis:

Answer 52

Restriction of food leading to significant low body wt for age, sex, developmental trajectory and physical health Intense fear of gaining weight or becoming fat, or persistent behavior that interferes with weight gain, even if already at low body wt Disturbance in the way the body is perceived or experienced, body image, undue influence of body wt or shape on self evaluation, or lack of recognition of seriousness of the current low body wt

Question 53

Anorexia Nervosa Many causes:

Answer 53

Genetic predisposition Personality traits of perfectionism and compulsiveness Family history of depression and obesity Peer, cultural, familial ideals of beauty Issues of control

Question 54

Bulimia Nervosa Formal Diagnosis:

Answer 54

Recurrent episodes of uncontrolled binge eating Recurrent inappropriate compensatory behavior Self-induced vomiting, laxative misuse, diuretics, or enemas, fasting and/or excessive exercise Binge eating and compensatory behavior >1/week for 3 months More difficult to identify > Often normal weight or sometimes overweight

Question 55

Female athlete triad

Answer 55

(Relative Energy Deficiency Syndrome) > Amenorrhea (at least 3 months without menstrual cycle) > Osteoporosis > Disordered eating

Question 56

Female Athlete Triad (Relative Energy Deficiency Syndrome)

Answer 56

Caloric deficit and decreased energy availability = Body attempts to restore energy balance by using less energy for growth, reproduction, and various other important bodily functions Somewhere around 25% of elite female athletes in endurance sports, ballet, and weight-class sports suffer from disordered eating and some variation of the female athlete triad

Question 57

National Eating Disorders Association offers the following tips:

Answer 57

Take warning signs seriously De-emphasize weight Don’t assume that reducing body fat or weight will improve performance Help other exercise professionals recognize the signs of eating disorders and be prepared to address them Provide accurate information about weight, weight loss, body composition, nutrition, and sports performance Have a broad network of referrals (such as physicians and registered dietitians) that may also be able to help educate your clients when appropriate

Question 58

Preventing Eating Disorders in High-risk Populations:

Answer 58

Emphasize the health risks of low weight, especially for female athletes with menstrual irregularities (in which case, referral to a physician, preferably one who specializes in eating disorders, is warranted) Avoid making any derogatory comments about weight or body composition Do not curtail athletic performance and gym privileges to an athlete or client who is found to have eating problems unless medically necessary Strive to promote a positive self-image and self-esteem in clients and athletes

Question 59

1. Hyponatremia is: A. Higher than normal blood sodium concentration. B. Lower than normal blood potassium concentration. C. Lower than normal uric acid level. D. Lower than normal blood sodium concentration.

Answer 59

D. Lower than normal blood sodium concentration.

Question 60

2. Your 18-year-old female client comes to you with a calcaneal stress fracture. She states that she started a running program to lose weight (although when you assess her BMI she underweight).  She is concerned that she cannot run now and doesn’t want to gain weight. Your response to her is:  A. To have her reduce her caloric intake by 300 calories a day in order to not gain any weight while she is recovering B. To deemphasize weight, while accurately going over her body composition and nutrition recommendations, particularly to help promote tissue healing C. To provide her with other forms of cardiovascular exercise while she cannot run in order to continue losing weight D. To curtail her exercise activity as you think she may be suffering from bulimia nervosa

Answer 60

B. To deemphasize weight, while accurately going over her body composition and nutrition recommendations, particularly to help promote tissue healing

Question 61

3. Which of these options describes the transfer of heat via electromagnetic waves traveling from a higher temperature object to a lower temperature object along a temperature difference? A. Conduction B. Convection C. Radiation D. Absorption

Answer 61

C. Radiation

Question 62

4. Why are older adults more susceptible than younger adults to both hot and cold stresses?  A. They are more prone to dehydration due to a diminished sense of thirst. B. They have a greater proportion of muscle tissue. C. They have increased thermoregulatory efficiency. D. They have increased subcutaneous fat.

Answer 62

A. They are more prone to dehydration due to a diminished sense of thirst.

Question 63

5. Which among the following is predominantly the most crucial element of a nutritional plan before exercising? A. Protein B. Amino acids and other fluids C. Carbohydrates D. Creatine

Answer 63

C. Carbohydrates

Question 64

6. Within how many minutes after completing exercise should adults consume a food rich in carbohydrates for the best recovery?

Answer 64

B. 30

Question 65

7. Which of the following is the transfer of heat when a liquid changes physical states by becoming a gas? A. Conduction B. Convection C. Radiation D. Evaporation

Answer 65

D. Evaporation

Question 66

8. On a hot and humid day, while your client engages in a moderate workout and experiences low sweating with fatigue, you conclude: A. Her exercise intensity might be lower than claimed due to minimal sweating. B. Insufficient pre-workout rest might be a contributing factor. C. There's a possibility of hyponatremia being a concern. D. Her core temperature has increased, causing elevated levels of circulating epinephrine and enhanced glycogen utilization, contributing to lactate build up , exhaustion and fatigue

Answer 66

D. Her core temperature has increased, causing elevated levels of circulating epinephrine and enhanced glycogen utilization, contributing to lactate build up , exhaustion and fatigue