aspects that make journals good
- published by professional organization
- open source=less good (lower standards)
- impact factor (based on how many articles, quality, citations, etc.)
why are long term events particularly challenging for the GI tract?
@ elite level, they have to deal with a large calorie input/hour with little to no GI blood flow
prevalence of GI symptoms in runners
30-90%
upper GI tract
mouth–>pharynx–>esophogus–>stomach–>duodenum–>jejunum–>ileum
lower GI tract
cecum–>ascending colon–>transverse colon–>descending colon–>sigmoid colon–>rectum–>anal canal–>anus
small intenstine length + function
7m long
water, bile, enzymes added to chyme
nutrient absorption
liver’s GI role
- process nutrients absorbed from SI
- produce bile
- detoxifiction
Pancreas GI role
- secretes digestive enzymes into duodenum that break down CHO, protein, and fat
- secretes insulin to bloodsteam
gallbladder
stores and concentrates bile
releases bile for fat digestion
large intestine GI role
absorbing water
nutrients have been absorbed at this point
continence
=waste is held in rectum through sphincters and pelvic floor muscles
why does exercise cause GI distress?
possibly:
aggressive diaphragm movement
abdominal contractions
intenstinal jarring (especially running, rectum is straight)
and blood being redirected to working muscle
splachnic hypoperfusion
motility
reduced blood flow due to vasoconstriction
motility of esophagus and reduced pyloric sphinctor tone
-reduced gastric emptying
-possibly increased intestinal permeability w/exercise
different symptoms in runners and cyclists
runners: lower due to pounding
cyclists: upper dues to pressure on abdomen and horizontal esophagus
why is delayed gastric emptying an issue?
- can lead to bacterial overgrowth
- can increase fluid in the intestine
- potential for toxins to cause symptoms
what is recommended CHO for minimal GI symptoms?
glucose/fructose mix or maltodextrin/fructose mix
reduce fiber
nutrition for GI issues in athletes
avoid trigger foods
stay hydrated
avoid fiber before events
morning food recommendations
low GI if there’s time for digestion
high GI just before racing
NSAIDs and GI issues
3-5x increased risk GI symptoms
- advil increases risk of intestinal bleeding
- if they cause issues, they shouldn’t be taken
1. reflux, upper GI bleeding in esophagus (common)
2. stomach and duodenum symptoms of gastritis, bleeding, perforation
3. permeability of intestine increased rarely
upper GI issues
heartburn acid reflux nausea vomiting bloating epigastric pain
gastroesophageal reflux likely mechanisms
- decreases in esophageal peristaltic activity
- dec. lower sphinctor tone
- inc. transient lower sphincter relaxation
GERD causes
smoking, obesity, pregnancy, overeating, exercise
what can GERD symptoms mimic?
asthma
stitch
likely spasm of diaphragm or gas trapped in colon
avoid solid food before exercise
runners diarrhea
more prevalent in competition-ie anxiety may be a factor
cause may be ischemia, increased motility, etc.
-reduce fiber and anti-diarrheals may be used occasionally (competition)
rectal bleeding
athletes may find blood in stool after events
mx unclear
recurrent bleeding=risk for anemia
traveler’s diarrhea causes
- bacteria=most common-salmonella, E Coli
- virus-norovirus, rotavirus
- parasites-giargia, cyclospora
imodium
anti-diarrheal med
slows gut motility (peristalsis) and reduces frequency of stools
only good for certain circumstances (eg when you don’t have access to a toilet)
protozoal diarrhea
5-10%
from unclean drinking water or person-to-person contact
-initially watery, then foul-smelling and fatty (steatorrhea)
-gradual onset, “relatively tolerable”
-malaise
cramps, bloating, flatulence, nausea, weight loss common
vomiting possible
protozoal diarrhea treatment
hydration and rest antiprotozoal medication (prescription)
bacterial diarrhea
sudden onset, uncomfortable
-boil, peel, cook, or forget
prevention of traveler’s diarrhea
- boil water for 3 min or use 2 drops bleach or 5 drops iodine
- ice is not safe
- alcohol does not sterilize water or ice
- look for carbonation to for reassurance of proper processing
- salads are unwise choices
- avoid condiments and steam tables
viral gastroenteritis
- stomach and intestines become inflammed–>pain, nausea, diarrhea, vomiting
- sometimes body aches, headaches, and fever, which are only usually w/viral infections
- treatment=oral rehydration and quarentine, hand washing, disinfecting w/chlorine
evaporation
- evaporation (from water to gas) requires heat-cooling effect
- more evaporation when low humidity
- garments play a role
radiation
transmission of heat energy from a surface
conduction
transfer of thermal energy from one region to another along a temperature gradient
- mesh promotes cooling
- cotton kills
convection
two types
- forced convection through blood flow (fluid is moving anyway)
- free convection through the flow of air around the body (heat causes fluid motion)
mild hypothermia
cold extremities shivering tachycardia tachypnoea urinary urgency mild incoordination
moderate hypothermia
apathy, poor judgement, slurred speech, amnesia
reduced shivering
dehydration
incoordination and clumsiness
severe hypothermia
inappropriate behavior loss of shivering arrhythmias pulmonary oedema hypotension, bradycardia reduced LOC, muscle rigidity
on-site management of hypothermic condition
- recognition!!! (monitor Tc if possible)
- remove from cold, wind, and wet
- insulation to prevent further loss
- nutritional an fluid support
- passive or active rewarming possible
- transport to medical facility if moderate to severe
passive rewarming
remove from cold environment + wet clothing
- replace with dry blankets/clothing
- in a pinch, plastic bag + insulation when no dry clothing is available
- space blankets not super useful cause they’re good for radiant, not convective heat loss
active rewarming
warm packs on key areas
- groin, axillae, torso
- heat torso to reduce afterdrop
superficial frostbite
affecting subcutaneous tissue
deep frostbite
affecting bone joint and tissue
frostnip
transient numbness with no residual damage
frostbite blisters
clear are better and can be drained
cloudy or bloody are worse and usually are not
-blisters contain harmful thromboxanes and prostaglandins
frostbite care
ibu
rewarming bath
aloe vera, dry, bulky dressings
eventual surgical management
why are elite XC skiers, swimmers, etc more susceptible to asthma?
high ventilatory rate
+long term training (inc. w/ inc. years of training and dec. after over time after retirement)
cold acclimatization
is possible
ideal protocol not studied
some evidence of 4-7 1 hr, 5C cold-air exposures over 14 days having an effect
why is exercise complicated in the heat?
- blood is transported to the periphery for cooling
- relative and actual central fluid deficit
- ->smaller SV and larger HR for given intensity
- also, splanchnic vasoconstriction to compensate for peripheral steal leads to GI and kidney adverse effects
heat exhaustion sx
- pale, cool, moist skin
- sweating profusely
- mm cramping, pain
- faint or dizzy
- headache, nausea
heat stroke sx
- abnormal mental status!
- flushed and hot dry skin
- BP may be elevated initially then reduced
- hyperventilation
heat illness risk factors
age above 65 alcohol, dehydration overweight poor fitness/sedentary poor acclimatization recent fever sunburn or other dry conditions
what medications would increase heat illness risk?
those that reduce sweating alter skin blood flow increase heat prod (metabolism) reduce cardiac contractility
wet bulb globe temp
index of heat stress that takes humidity into account
exertional heat stroke
mental status changes + Tc >40
-metabolic heat production contributes=difference b/t exertional and classic heat stroke
heat stroke causes of death
improperly measuring core temp delayed treatment -reduce temp below 40 w/in 30 min -use towels if ice bath unavailable rapid return to play w/out full determination and elimination of cause
hyponatremia
serum or plasma sodium below normal reference range (less than 135mmol/L)
hyponatremia sx
early: bloating, puffiness, nausea, vomiting, headache
later: altered mental status, obtundation, coma, seizeres, respiratory distress from pulmonary edema
body weight gain in most cases
how does hyponatremia happen?
excessive consumption of fluids in excess of total loses
- eg insensible losses from transcutaneous, respiratory, and GI losses
- and sweat and renal fluid losses
hyponatremia risk factors
excessive drinking weight gain during exercise low body weight -event inexperience -NSAIDs -high availability of fluids -events >4 hours
hyponatremia treatment
recognition
ABC’s
IV access
100mL of 3% NaCl solution and EMS transfer immediately
heat illness prevention
ample fluids, sal-containing solutions and salty foods
drink to thirst
replace fluids w/1liter per 2 pounds lost
acclimatization to heat
is possible
greater affect in untrained individuals
90min duration in 40 C for 5 days
-60 relative humidity
how does heat acclimatization occur?
- improved cutaneous blood flow (from core to periphery)
- lower sweating threshold and increased sweat output
- decreased Na in sweat
- lower skin, core temp, and HR for given intensity
- less CHO metabolism
what has the opposite effect to heat acclimatization?
age
case: fatigue, poor appetite, hypertension, tachycardia, poor sleep
possible causes: anxiety, anemia, general caloric deficit, exercise induced bronchoconstriction
overtraining
mono or other virus
test for: iron (blood) thyroid hormones, asthma, white blood cells, glucose, look at training volume + nutrition
overreaching
accumulation of training stress that leads to short term performance decrements with or without related psychological and physiological signs and symptoms of maladaption
overtraining
accumulation of training resulting in long term decrement in performance capacity with or without related physiological and psychological signs and symptoms of maladaption in which restoration may take weeks to months
overtraining prevalence
60% of elite runners
also happens in packs sometimes
-like teams with terrible coaches
overtraining vs overreaching
spectrum
overreaching has rapid recovery w/rest
-w/in days but at least by 2-3 weeks
spectrum of overreaching
functional-recovery in days weeks (training camp for eg)
non-functional-recovery in wks to months-stagnation or dec. in performance capacity
overtraining: months to…, performance decreases
how is overtraining diagnosed?
by excluding all other possible causes
- rule out all other phenomena + profile of mood states
- also performance testing if there’s baseline data (time trial to exhaustion)
- hormones not super good-variable by lots of other things
name 10 other things overtraining symptoms could be due to
anxiety mono insufficient sleep dehydration exercise-induced asthma iron deficiency eating disorders hypothyroidism upper respiratory infection
general and physical overtraining symptoms
workouts more difficult
- early fatigue
- faster HR w/less effort
- dec. strength
- dec. coordination
- persistent fatigue
- ongoing mm soreness
- loss of appetite
- inc. aches and pains
- inc. in overuse injuries
- frequent colds or infections
what is the subjective psychological evaluation?
- fatigue ratings
- mood states (dec. pos. and inc neg. feelings)
- mm fatigue ratings and inc. recovery time
- perceived exertion during constant exercise load (inc.)
cardiovascular factors in OTS
resting moring HR not super useful: sometimes higher, sometimes lower
-HR variability may be useful down the road
weight and nutrition in OTS
individual variation, inc. or dec. more than normal
OTS risk factors
general health general nutrition mood state personality (type A) stressors intensity of training volume of training social, economic, and psychological stressors environmental conditions infections travel
OTS treatment
rest
proper early diagnosis
6-12 wks
possibly address other stress with counseling
*collaboration with athlete, coach, and team or patient’s physician