Environmental Physiology - Final Exam Flashcards
What are the stages of sleep?
Transition phase, light sleep, start of slow wave, slow wave, rapid eye movement (REM)
Slow wave sleep
Very restful (deep), BP, breathing rate and metabolism slow down, dreamless sleep.
REM Sleep
5-30 minutes long, irregular heart rate and breathing rate, active dreaming and body movements.
Biorhythms
Can last a few minutes to a few months. Immune function can suffer. Diurnal pattern (25 hours)
Examples of biorhythms
Kidney fxn, HR, BP, VE, Tcore, O2 consumption, CATs, reaction times, hand-eye coordination.
Circadian Rhythm
External cues: zeitgebers or synchronizers - Sun.
Internal cues: Are regulated by suprachiasmatic nucleus - neuroendocrine and thermoregulatory rhythms are controlled by SCN.
Enhances biological fxn and helps adjust to natural changes in environment.
Normal nightly requirement of sleep
7-hours
Sleep Deprivation
Long term - more than 45 hours
Short term - less than 45 hours
Partial SDEP - less than 7-24 hours
Physiological Responses
Tcore, Tskin and catecholemines all affected, cognitive function decreases
Performance effects
Larks - morning workouts
Owls - afternoon workouts
Jet Lag
Results when circadian rhythms are thrown out of sync.
Circadian rhythms shift 1 hr/day
West coast - later 1 hr
East Coast - earlier 1 hr
It becomes increasingly difficult to adjust when an individual crosses over….
5+ time zones
Athletes require how man days to recover from international travel?
2-10 days
Recommendations for counteracting jet lag
Arrive to destination early (14 days minimum)
Exercise upon arrival
More alcohol
Alter diet
Sleep loss, health, and performance
Missing 4-hours reduces immune function by 28%
Motor vehicle fatalities are commonly caused by fatigue - 20% have fallen asleep at the wheel
18 million Americans suffer from sleep apnea
60 million Americans suffer from insomnia
Who responds to SDEP better?
Larks, anxious people and old people
Sleep and Physical Fitness
17-19 hours of SDEP = BAC of 0.05%
Physical performance impaired
Sleep and Weight Control
Increased ghrelin, decreased leptin, satiety is altered, hungrier with SDEP
SDEP compromises carbohydrate metabolism
Increased cortisol, decreased insuiln sensitivity (hyperglycemia), decreased growth hormone can lead to obesity and diabetes.
Increased insulin resistance, decreased glucose sensitivity.
Forced Expiratory Volume
Maximal air exhale in 1 second.
Forced Vital Capacity
Maximal inhale and max exhale
Forced midexpiratory flow
Middle of forced exhalation (FEV0.25 - 0.75)
Diffusing capacity of the lung
How well O2 and CO2 is exchanged
Primary Pollutants
Exert physiological influence directly from source of pollution
Secondary Pollutants
Formed by the interaction of primary pollutants with other compounds, UV light and each other.
Carbon Monoxide
Primary that comes from automotive exhaust and cigarette smoke.
Physiological Effects of Carbon Monoxide
Hemoglobin has a 230 times greater affinity for carbon monoxide. CO binds to iron rich compounds such as myoglobin in skeletal muscle and cytochrome in mitochondria, prevents O2 release.
Cytochromes within mitochondria negatively impact by blocking the production of ATP by interfering with the ETC an ox. phos.
2.5-3% needed for effect (normal blood levels =
Maximal Performance Effects of CO
Maximal O2 and exercise time decreases because of decreased O2 being released. Anaerobic not affected.
Submaximal Effects of CO
Aerobic performance depends on parts per million mg/L
NO2
Primary pollutant
Heavy motor traffic, aircraft engine combustion, firefighting and cigarette smoking
Physiological Effects of NO2
People with respiratory/pulmonary disorders are more susceptible
When inhaled in high concentrations, pulmonary dysfunctions can persist for 2.5-13.5 years
Cause breathlessnss and diminished exercise tolerance
Maximal Performance Effects of NO2
Inhalation leads to mild irritation of upper respiratory tract and impairment of mucocilliary activity in the bronchial tubes.
Submaximal Effects of NO2
Large quantities can lead to respiratory dysfunction
Small quantities = no effect
Pollutant standard for NO2 = 0.05ppm
Sulfur Dioxide (SO2)
Primary
Released from sulfur-containing fossil fuels
Physiological Effects of SO2
Induces bronchoconstriction and upper respiratory tract irritation.
Airway resistance increases at rest as the volume of inspired air increases
At res, VE increases SO2 delivery to bronchial tissue and decreases the % of air inhaled through the nose (nasal scrubbing bypassed and bronchoconstriction increases)
Nasal Scrubbing
Absorbs 99% of SO2 during quiet breathing
Allows increased volume of SO2 into the lungs, thus increasing bronhoconstriction.
Maximal Performance and SO2
No studies conducted
Submaximal Performance and SO2
Bronchoconstriction is further exacerbated by increased ventilation during exercise, which also inhibits exercise performance.
At 1.0-3.0 ppm SO2, performance begins to decrease
At 5.0 ppm SO2, mucus cannot be cleared effectively and expiratory flow is decreased
Asthma and SO2
Attacks may be triggered by 0.2-0.5 ppm SO2 (2ppm for bronchospasm in non-asthmatics)
May be further exacerbated by cold, dry air.
Fine Particulates
Primary.
Dust, dirt, drops of liquid, acidic aerosols, wood and tobacco smoke, pollen, bacteria, sulfuric acid
Physiological Effects of Fine Particulates
Older adults, pulmonary/CV disease (asthma), children and babies affected more.
Effects of Fine Particulates Depends ON
Particle size, total particle mass, chemical composition, deposition patterns, oral vs nasal breathing, and defense mechanisms of the lungs.
Effects of Large Paricles
Deposited in nasopharyngeal region and can cause inflammation, congestion and ulceration
Effects of Smaller Particles
Deposited in tracheobronchial region and can cause the stimulation of bronchospasms, bronchial congestion and bronchitis. Smallest particles can reach alveoli.
Other side effects - eye irritation, lung and throat irritation, trouble breathing, lung cancer, problems with babies at birth (low birth weight)
Defense Mechanisms
Mucuciliary transport and phagocytosis are two utilized to try and clear the lungs.
When particle pollution increases, stay indoors, choose easier outdoor activities, and avoid busy highways.
Aerosols
Secondary
Smoke, fog, mist
Physiological Effects of Aerosols
Ammonium sulfate and ammonium bisulfate can enter into blood without affecting pulmonary system or clinical systems of exercising normal and asthmatic people.
Sulfuric acid aerosols in high concentrations can cause death of cells in nasal passage, new cell replication of epithelial cells.
What is an aerosol?
Suspension of ultramicroscopic solid or liquid particles in air or other gas.
Not only affect pulmonary system, but also absorbed into blood stream, affecting other organs.
Ozone
Secondary
Filters out harmful UVR
Should not exceed 0.12ppm/hr or 0.20 ppm
Inhalation of O3 impairs pulmonary function and causes respiratory distress (inreased O3 = increased ventilation)
Exercise and Ozone
Cough, shortness of breath, throat tickle, raspy throat, nausea and headache
Endurance performance is diminished at 0.20-0.40ppm
VO2max decreases
Physical training does not alter response
Hot environment = BAD
Older individuals demonstrate blunted response
Ozone and inflammation
At rest, O3 exposure stimulates the production of neutrophils and chemical mediators within the nasal cavity and upper airways involved in inflammation
During exercise, inflammation within deep tissue of the lung
NSAIDS help reduce chemical mediators and (IL-6)
Ozone adaptation
Adapt similarly to SO2
Following successive exposures, pulmonary impairment is reduced and fewer clinical symptoms
Adaptation lost after 7 days
Bronchial Asthma
Narrowing of respiratory airways via contraction of smooth muscle lining the airway and increased mucus secretion
S/S - Shortness of breath, wheezing and coughing
Treatment of Bronchial Asthma
Short term - Beta-2 agonist
Induce bronchodilation, skeletal muscle contraction an GNG and glycogenolysis (increase blood glucose)
Onset occurs within 5-minutes, lasts 2-6 hours
Long-Acting Treatment of Bronchial Asthma
Albuterol, salmetrol are ineffective for treating immune response
Pill or inhalent every 12 hours
Fixed-dose combination (Advair)
Decreases use of short-acting beta-2 agonists, nocturnal asthma, improved EIB protection
Nasal Allergy
Histamine is release from airborne substance entering nose
S/S - Inflammation, swelling, increased fluid in nose, sinus headache, plugged ears, nasal drip and itchy eyes.
Treatment of Nasal Allergy
Prevent histamine from being released or binding to receptor
Administered orally, lipid-soluble (cross BBB) and cause sedation (non-sedating antihistamines do not cross BBB)
Head-down bed rest
Subjects remain confined to a bed for up to a year in either a horizontal or head-down tilt position (simulates time in space) before being accelerated in a centrifuge at forces near 3g (simulates travel into or back from space). This method of simulating microgravity has allowed detailed analysis of changes in immune function, hormonal changes, CV changes and stress placed on body.
Wheelchair confinement for paraplegics
Postural hypotension mimics long space flight times (21+ days). During postural or orthostatic hypotension, an individual remains in an upright position without bearing weight on the legs (or keeping knee locked) for extended periods. Venous return decreased. Lack of blood flow to brain can lead to cerebral ischemia, causing an individual to faint. Short-term upper body exercises, HR, BP and hormonal responses can be studied. Influences orthostatic stability upon return from a microgravity environment.`
Parabolic flights
Astronauts in training will board an aircraft that ascends rapidly at a 45 degree angle and then descends rapidly at a 45 degree angle. There will be a period of about 30 seconds during the apex of the flight where a near-zero-g effect may be experienced. 60 flights per day for a week.
