Environmental Considerations for Exercise Prescription

Question 1

As we go higher in altitude, performance will…

Answer 1

decrease (in relation to aerobic performance)

Question 2

How much Physical performance decreases with increasing altitude >3,937 ft (1,200 m) depends on…

Answer 2

1) How they become acclimatized to the environment, 2) How much time they are at elevation, 3) Greater physical activity, 4) The higher the altitude, 5) The larger the individual (muscle mass increases)

Question 3

A progressive decrease in atmospheric pressure associated with ascent to higher altitudes reduces the…

Answer 3

partial pressure of oxygen in the inspired air, resulting in decreased arterial oxygen levels; (Low altitude <3,937 ft (1,200 m), Moderate altitude 3,937 and 7,874 ft (1,200–2,400 m), High altitude between 7,874 and 13,123 ft (2,400–4,000 m), Very high altitude >13,123 ft (4,000 m))

Question 4

Altitude Acclimatization Prevention and Treatment

Answer 4

The best countermeasure to all altitude sickness; Takes 7-14 days, Minimizing sustained exercise/physical activity, Adequate hydration and food intake will reduce susceptibility to altitude sickness; Descend when possible! (only cure)

Question 5

Primary Acclimatization

Answer 5

Increased Red blood cell production which helps in delivery, also water retention

Question 6

Before Acclimatization occurs…

Answer 6

Altitude sickness is a problem

Question 7

As elevation increases,

Answer 7

Time to perform physical task increases

Question 8

Exercise in High Altitude Environments Medical considerations

Answer 8

Altitude Illnesses (Rapid ascent to high and very high altitude increases individual susceptibility to altitude illness)

Question 9

The primary altitude illnesses are…

Answer 9

Acute mountain sickness (AMS), High altitude cerebral edema (HACE), High altitude pulmonary edema (HAPE)

Question 10

Acute Mountain Sickness (AMS)

Answer 10

Initial and most common illness; Symptoms include headache, nausea, fatigue, decreased appetite, and poor sleep and, in severe cases, poor balance and mild swelling in the hands, feet, or face; Develops within the first 24 h of altitude exposure; Its incidence and severity increases in direct proportion to ascent rate and altitude;
If ascent is stopped and physical exertion is limited, recovery from AMS occurs over 24–48 h after symptoms have peaked.

Question 11

Chronic Acute Mountain Sickness (AMS)

Answer 11

Can turn into High altitude cerebral edema (HACE) (less common), High altitude pulmonary edema (HAPE) (more common)

Question 12

High Altitude Cerebral Edema (HACE)

Answer 12

Potentially fatal, although not common, illness that occurs in <2% of individuals ascending >12,000 ft (3,658 m); An exacerbation of unresolved, severe AMS; Most often occurs in individuals who have AMS symptoms and continue to ascend.

Question 13

High Altitude Pulmonary Edema (HAPE)

Answer 13

Potentially fatal, although not common, illness that occurs in <10% of individuals ascending >12,000 ft (3,658 m); Individuals making repeated ascents and descents >12,000 ft (3,658 m) and who exercise strenuously early in the exposure have an increased susceptibility to HAPE.

Question 14

Rapid Ascent

Answer 14

Using any HR-based exercise prescription (relative intensity rather than absolute intensity) at altitude as at sea level provides a similar training stimulus as long as the weekly number and durations of the training sessions are also maintained.

Question 15

During the first few days at high altitudes, individuals should…

Answer 15

Minimize their exercise/PA to reduce susceptibility to altitude illness; After this period, individuals whose Ex Rx specifies a THR should maintain the same exercise HR at higher altitudes. The personalized number of weekly training sessions and the duration of each session at altitude can remain similar to those used at sea level for a given individual.

Question 16

For the same perceived effort, jogging or running pace will be…

Answer 16

reduced at altitude relative to sea level, independent of altitude acclimatization status.

Question 17

Absolute Intensity

Answer 17

Setting a pace for the individual (METS, MPH, etc)

Question 18

Many factors determine cold temperature effects on physiological strain including:

Answer 18

Environment, Clothing, Body composition, Health status, Nutrition, Age, Exercise intensity (In most cases, exercise in the cold does not increase cold injury risk)

Question 19

Relative Intensity

Answer 19

Such as HR based exercise prescription (possibly RPE), so individual can self monitor at changing altitudes.

Question 20

Does altitude effect anaerobic exercise?

Answer 20

No it does not effect strength or power but aerobic is used for recovery); May still need to be adjusted because of this

Question 21

Exercise in Cold Environments (sub-freezing or close to freezing)

Answer 21

Inability to maintain thermal balance/ cord body temperature (i.e., immersion, rain, low ambient temperature with wind) will increase exercise-related cold stress (Hypothermia, frostbite, Diminished exercise capability / performance)

Question 22

Exercise-related cold stress may increase the risk of…

Answer 22

Morbidity and mortality in at-risk populations (CVD and asthmatic conditions)

Question 23

Risk Factors for Hypothermia:

Answer 23

Immersion, Rain, Wet clothing, Low body fat, Older age (i.e., ≥60 yr), Hypoglycemia.

Question 24

Frostbite

Answer 24

Occurs when tissue temperatures fall lower than 0° C (32° F). (Air temperature, Wind speed, and Wetness); Be sure to account for man-made wind (e.g., running, skiing; Most common in exposed skin (i.e., nose, ears, cheeks, and exposed wrists) but also occurs in the hands and feet; Contact frostbite may occur by touching cold objects with bare skin, particularly highly conductive metal or stone that causes rapid heat loss. (Offset w clothing)

Question 25

Negative effect health conditions on exercise in Cold environments

Answer 25

Low body fat, Older age, Low body sugar (hypoglycemia)

Question 26

Non- Freezing Cold Injuries (NCFI’s) (More Common)

Answer 26

Typically occur when tissues are exposed to cold-wet temperatures between 0-15 °C (32-60 °F) for prolonged periods of time; These injuries may occur due to actual immersion or by the creation of a damp environment inside boots or gloves, as often seen during heavy sweating; The most common NFCIs are trenchfoot and chilblains.

Question 27

Trenchfoot and Chilblains.

Answer 27

The initial skin color is red but soon becomes pale and cyanotic if the injury is more severe.

Question 28

Clothing Considerations for Exercise in Cold Environments

Answer 28

Adjust clothing insulation to minimize sweating, Use clothing vents to reduce sweat accumulation, Do not wear an outer layer unless rainy or very windy, Reduce clothing insulation as exercise intensity increases, Do not impose a single clothing standard on an entire group of exercisers, Wear appropriate footwear to minimize the risks of slipping and falling in snowy or icy conditions.

Question 29

Shoveling snow

Answer 29

↑ HR to 97% HRmax and systolic BP to 200 mm Hg. (Walking in snow that is either packed or soft significantly increases energy requirements and myocardial (Individuals with atherosclerotic CVD)

Question 30

Swimming in water <25° C (77° F) may be a threat to individuals with…

Answer 30

CVD

Question 31

When the amount of metabolic heat exceeds heat loss,

Answer 31

Hyperthermia (i.e., elevated internal body temperature) may develop; Sweat that drips from the body or clothing provides no cooling benefit.

Question 32

Sweat losses vary widely when exercising in Hot environments depending on…

Answer 32

Gender, Hydration status, Amount and intensity of PA, Clothing, Protective equipment and environmental conditions.

Question 33

Heat acclimatization (1-2 weeks)

Answer 33

Results in higher and more sustained sweating rates; Aerobic exercise training has a minimal effect on sweat rate responses

Question 34

Heat acclimatization vs Cold

Answer 34

Cold: clothing and expectations need to be modified, Heat: Physiological changes take time to occur

Question 35

During exercise-induced heat stress, Dehydration increases…

Answer 35

Physiologic strain
Core temperature, HR, and RPE
Cardiac Drift

Question 36

Dehydration will exacerbate core temperature elevations

Increases of…

Answer 36

0.1 °C to 0.2 °C (0.2 °F to 0.4 °F) with each 1% of dehydration.

Question 37

Dehydration of ≥2% loss in body mass negatively impacts…

Answer 37

Endurance exercise performance, while strength and power are negatively affected to a smaller degree.

Question 38

Special Considerations for

Heat acclimatization adaptations

Answer 38

Decreased rectal temperature, HR, and RPE; Increased exercise tolerance time, Increased sweating rate, A reduction in sweat salt.

Question 39

Acclimatization results in the following:

Answer 39

Improved heat transfer from the body’s core to the external environment, Improved cardiovascular function, More effective sweating, Improved exercise performance and heat tolerance.

Question 40

Seasonal acclimatization will occur gradually during…

Answer 40

late spring and early summer months with sedentary exposure to the heat. However, this process can be facilitated with a structured program of moderate exercise in the heat across 10–14 d to stimulate adaptations to warmer ambient temperatures

Question 41

Counteracting dehydration

Answer 41

Fluid replacement (males sweat more than females)

Question 42

Fluid Replacement Guide

Answer 42

Measuring body weight before and after exercise

Question 43

Active individuals should drink…

Answer 43

0.5 L (1 pint) of fluid for each pound of body weight lost; A paler urine color indicates adequate hydration; a darker yellow/brown color, the greater the degree of dehydration

Question 44

Sweating more and sweating sooner=

Answer 44

Acclimatization which is good!

Question 45

Fluid Replacement Recommendations Before Exercise

Answer 45

Drink 5-7mLkg at least 4 hours before exercise (12-17oz for 154lb individual); If urine is not produced or is very dark drink another 3-5mLkg 2h before exercise (Sodium containing beverages or salted snacks will help retain fluid)

Question 46

Fluid Replacement Recommendations During Exercise

Answer 46

Monitor individual body weight changes to estimate sweat loss; Composition of fluid should include 20-30mEqL of sodium, 2-5mEqL of potassium, and 5-10% carbs; Prevents a >2% loss in body weight (Amount and rate of fluid replacement depends on individual sweating rate, environment, and exercise duration)

Question 47

Fluid Replacement Recommendations After Exercise

Answer 47

Consumption of normal meals and beverages will restore euhydration, If rapid recovery is needed drink 1.5L*kg of body weight lost (Goal is to fully replace fluid and electrolyte deficits; Consuming sodium will help recovery by stimulating thirst and fluid retention)

Question 48

Typical Cause of Hyponatremia

Answer 48

Overdrinking Hypotonic Fluid; Altered normal blood sodium concentration (typically <135 mEq · L−1)

Question 49

Hyponatremia is most common in…

Answer 49

Long duration physical activities; Fluid replacement by hypotonic fluid (water) alone in excess of sweat losses (typified by body mass gains).

Question 50

Prevention of Hyponatremia

Answer 50

Over-drinking leads to an excess of sweat rate; Consume salt-containing fluids or foods

Question 51

Exertional Heat Illnesses – Heat Cramps Multifactorial Cause

Answer 51

May be more related to muscle fatigue and neuronal excitability compared to hydration status or electrolyte concentrations; Water loss, and significant sweat sodium may be a contributing factors

Question 52

Exertional Heat Illnesses – Heat Syncope

Answer 52

Temporary circulatory failure caused by the pooling of blood in the peripheral veins, particularly of the lower extremities; Occurs more often among physically unfit, sedentary, and nonacclimatized individuals; Caused by standing erect for a long period or sudden cessation of strenuous exercise

Question 53

Heat Syncope Symptoms and Recovery

Answer 53

Light headedness to loss of consciousness; Recovery is rapid once individuals sit or lay supine

Question 54

Exertional Heat Illnesses – Heat Exhaustion

Answer 54

Occurs during exercise/PA in the heat; Body cannot sustain necessary cardiac output needed to support skin blood flow for thermoregulation and blood flow for metabolic requirements of exercise; Fatigue and progressive weakness without severe hyperthermia; Oral fluids are preferred for rehydration in individuals who are conscious (Intravenous fluid)

Question 55

Intravenous fluid administration facilitates…

Answer 55

Recovery in those unable to ingest oral fluids or who have severe dehydration.

Question 56

Exertional Heat Illnesses – Exertional Heatstroke

Answer 56

Caused by hyperthermia
Elevated body temperature (>40 °C or 104 °F); Profound central nervous system dysfunction, Multiple organ system failure that can result in delirium, convulsions, or coma.

Question 57

Greatest Risk for Heatstroke

Answer 57

Very high intensity exercise of short duration OR Prolonged exercise when the ambient wet-bulb globe temperature (WBGT) exceeds 28 °C (82 °F). (It is a life-threatening medical emergency)

Question 58

Exercise Prescription in Hot Enviroments

Answer 58

Individuals whose Ex Rx specifies a target heart rate (THR) will achieve this THR at a lower absolute workload when exercising in a warm/hot versus a cooler environment; As heat acclimatization develops, a progressively higher exercise intensity will be required to elicit the THR; The first exercise session in the heat may last as little as 5–10 min for safety reasons but can be increased gradually; Allow at least 3 h, and preferably 6 h, of recovery and rehydration time between exercise sessions

Question 59

Rhabdomyolysis

Answer 59

a syndrome characterized by muscle necrosis and the release of intracellular muscle constituents into the circulation.

Question 60

Rhabdomyolysis is

caused by a number of items…

Answer 60

Genetic defects, trauma, muscle hypoxia…HYPERTHERMIA, EXERCISE

Question 61

Rhabdomyolysis is characterized clinically by…

Answer 61

Myalgias, red to brown urine due to myoglobinuria, and elevated serum muscle enzymes (including creatine kinase) . The degree of muscle pain and other symptoms varies widely
Muscle pain, when present, is typically most prominent in proximal muscle groups
Also present  fever, tachycardia, nausea and vomiting, and abdominal pain

Question 62

Rhabdomyolysis CK Rise

Answer 62

2 – 12 hours following exercise…peak within 24 – 72 hours

Continued muscle injury or the development of a compartment syndrome may be present.

Question 63

Common Complication of Rhabdomyolysis

Answer 63

Acute kidney injury (AKI, acute renal failure)

Question 64

The reported frequency of AKI ranges from…

Answer 64

15 to over 50 percent

↑ Risk: Dehydration, sepsis, and acidosis (Compartment Syndrome, Muscle wasting)