K409 Exam 3 Study Guide
K409 Exam 3 Study Guide SPH-K 409
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This 21 page Study Guide was uploaded by Zoe Goldhirsh on Sunday April 17, 2016. The Study Guide belongs to SPH-K 409 at Indiana University taught by Robert Chapman in Spring 2016. Since its upload, it has received 19 views. For similar materials see Exercise Physiology in Nursing and Health Sciences at Indiana University.
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Date Created: 04/17/16
Zoe Goldhirsh K409 Exam 3 Study Guide Cardiovascular/Cardiopulmonary Adaptations to Training: Overload Principle: In order for adaptations to occur to allow the body to best be able to handle specific stimuli is to overload the system. Overload can be controlled by manipulating combination s of training; frequency, intensity, mode, duration, density and recovery. -Providing a greater stress or load on the body than normally accustomed to in order to increase fitness Specificity Principle: what you do in the gym should be relevant and appropriate to your desired outcome. Training must go from general at the beginning to specific as the program progresses. -Specificity applies to energy system being used, muscle groups being used and mode of exercise. Individual Differences Principle: Not everyone can respond to the same programs, you always have to tweak for individual differences. The training response to exercise can be influence by a variety of factors including but not limited to: state of training (how fit), quality of training (what you’ve been doing), quality of recovery and genetics. Reversibility Principle: The beneficial effects of exercise training are transient and reversible. After an extended time of absence from training (about 7 days), for every additional day off, it is generally accepted that it takes two days to recapture the same fitness (after 7 days off, an additional 3 days off from training required 6 days of training to get back to the same fitness level) Vascular (and muscle metabolic) adaptations with training: 1. Mitochondria have a greatly increased capacity to generate ATP by oxidatively 2. Increase in size and number of mitochondria 3. Increase in myoglobin content 4. Increase in muscles ability to mobilize oxidize fat as a fuel 5. Increases glycogen storage within muscle and liver 6. Increased capillarization of muscle *Adaptations in muscle and vascular systems with aerobic training primarily affect oxygen extraction (decreased venous oxygen content, expanding/increasing a-VO2 difference) Cardiac adaptations with Training: Heart Size: -Weight (mass) of the heart increases (left ventricular wall thickens/hypertrophy) -Volume of the heart increases (left ventricular end0diastolic volume increases) *Of these two adaptations, volume/diameter of the heart increasing has a great influence on cardiac function because the more you can fill the heart the better it can function/perform Stroke Volume: -Increases significantly during rest and exercise with training Heart Rate: -Heart rate at rest is reduced -Heart rate at any submaximal workload is reduced -Heart rate during recovery is reduced (recovers to a lower heart rate faster with training) -Maximal heart rate may be reduced slightly *Heart rate can show variability in response to exercise based on the individual and based on hydration, heat, training state/ overtraining Cardiac Output/Blood Flow: -Increases in maximal cardiac output with training (due to increase in SV) -Higher max velocityHigher max Cardiac output -Cardiac output at any submaximal workload will usually remain the same after training -May decrease slightly because of improved economy, increased a-vo2 difference, re- direction of blood flow to muscle -Blood flow is distributed to the most active fiber with training (muscles being used) Vascular/Blood Pressure: -Resting BP decreases (about 6-7 mmHg) in hypertensive and borderline hypertensive individuals after chronic training -At VO2max, SBP is usually slightly increased and DBP is usually slightly decreased A-vO2 difference: -After chronic training, a-vO2 will typically expand -Increase in exercise intensity = Decrease in mixed venous content Blood Volume Adaptations with Training: -Total body blood volume increases with training -Results primarily from increases in plasma volume -Increase in ADH, increase in plasma proteins -Plasma increases because you make more proteins/electrolytes and the high osmolarity will draw in more water to dilute them (increase in plasma) -Increases in red cell volume are SMALL -Even though there is an increase in RBC it is much smaller than the increase in plasma therefore the hematocrit level decreases with endurance training Pseudoanemia: a reduction in Hb and Hct levels because of training not actually real anemia *An increase in plasma volume/blood volume also causes an increase in SV (and thus VO2max): this helps maximize/protect cardiac function Respiratory Adaptations with Training: -State lung volumes remain essentially unchanged after training -TLC: ***remains unchanged -VC- may increase only slightly -RV- may increase only slightly -Total volume of blood the lungs can hold (max pulmonary blood volume) remains unchanged after training -Because SV and Q increases and pulmonary blood volume stays the same, the transit time of a RBV through the lung is reduced Ventilation: (after training) -At rest is usually unchanged -During submaximal exercise is slightly reduced (usually due to slightly lower fb) -During maximal exercise is substantially increased (due to increase in both TV and fb) *The more fit you are the less you breath ONLY during submaximal exercise Global changes with training that affect performance: -Increase in VO2max -Typical improvement of 15-20% from normal untrained to trained -Ultimately, genetically limited (in terms of range and probability) -Increase in lactate threshold -Can improve from around 60% of VO2max (untrained) to as high as 90% of Vo2max (after training) -Improvement in economy Factors that affect the response to aerobic training: -(Follows the individual differences principle) -Level of conditioning/VO2max before training -Higher the training level/VO2maxx the smaller the improvements with training -Genetics/Heredity -Studies with twin pairs and siblings indicate that heredity account for ~25-50% of the variance in VO2max Body Composition: *Just measuring weight is a poor indicator of overall health and fitness *Overweight does not necessarily equal overfat (height-weight tables are largely ineffective at predicting healthy weight status) Composition of the Human Body: -Two compartment model: dividing all body tissue into fat mass and fat free mass -Fat mass: 1. Essential fat (not possible to live without) 2. Sex specific fat 3. Storage Fat -Fat free mass: includes all other tissues like bone, muscle, water and “other” *The only completely accurate ways to measure body composition is after death (“sacrifice the animal”) and separate out fat and fat free tissues (usually done via blender and electrical separation) Hydrostatic Weighing/ Underwater weighing/ Densitometry/ Archimedes Principle: -Uses a measure of body density, to estimate the percentage of fat mass and fat free mass -Dbody=Mbody/Vbody (D=M/V) -Obtaining Volume of body is more difficult than mass of body -Most common technique is water displacement or air displacement -(Measure the volume of the water that spills over the sides once placed in water) -Problems: messy, difficult to deal with the water, hard to execute, accuracy in measuring volume -Archimedes principle: Weight underwater= Dry weight – weight of water displaced -We can measure for dry weight and underwater weight easily and then can solve for water displaced to use for V -Siri Equation: %Fat= (495/Dbody) – 450 *Potential source of error is that siri only tested it on 6 human cadavers *Assume you account for air that could booey you up (RV, bubbles on hair will make you lighter underwater, less dense) Assumptions: -Density of each type of tissue of the fat free mass is constant -The proportion of each tissue type in the fat free mass is constant across individuals -RV is accurately estimated ** If you overestimate an individuals RV, density would be higher and percent fat would be lower than what it really is Less Dense More fat The Bod Pod: same concept of measurement as water displacement expect using air displacement instead -Less mess, a lot more expensive Skinfolds: assumes that measurements of subcutaneous fat thickness will allow an estimate of total body fat stores *Skinfolds measurements are plugged into a prediction equation *Always done on the right side of the body *Equations are population specific, meaning that percent fat will be fairly accurately predicted for subjects similar in age, sex, and state of training, fatness and race. *Common areas are: triceps, subscapula, suprailliac crest, abdominal, and upper thigh Bioelectrical impedance analysis (BIA): Based on the principle that electric flow through a tissue is dependent on the water and ionic content of that tissue. Since fat tissue is essentially anhydrous, it will have high impedance to electrical current flow *Fat is not a good electrical conductor *Fat free mass is food conductor of electricity What is measured: resistance to flow of electrical current Factors that lead to error in measure: hydration status Dual X-ray absorptiometry (DXA scan) Advantages: can differentiate between subcutaneous fat and visceral fat (can tell you actual % between 2 components) *People with higher % of the fat mass as visceral fat are at greater risk for certain clinical disorders (heart attacks, type 2 diabetes) OBESITY: *The strongest correlating factor (after genetics) appears to be physical activity level, particularly before the end of puberty *Fat accumulation can occur by increasing the SIZE of the adipose cell (fat hypertrophy) and by new fat cell formation (fat hyperplasia) *The higher number of fat cells you have the more obese you are ***It appears that cell number is FIXED at the end of puberty/beginning of adulthood. Weigh gain in adults is a result of an increase in fat cell size*** -Fat content per cell was 35% greater in obese individuals than non- obese -Total number of fat cells was over 3X greater in these obese subjects Spot reduction: -Negative caloric balance created through regular exercise can contribute to a reduction in overall body fat – not selectively from exercised areas, but from total body reserves and usually from the areas of greatest fat concentration Effect of dieting on resting metabolic rate: -When you restrict your calories you can lose weight but you lose less than what you expect because when you restrict your calories your resting metabolic rate goes down so you don’t burn as many calories Clinical Definitions: -Height/Weight Tables: people are considered obese when they weigh more than twenty percent of their desirable weight as listed in the tables -Body Mass Index: although different BMI standards have been published for increased risk of disease for men (>27.8 kg/m2) and women (27.3 kg/m2), a combined categorization has been derived from the epidemiological literature: Acceptable range: 20-25 Mildly overweight: 25.1-27 Moderatly overweight/obese: 27.1-30 Markedly overweight/obese: 30.1-40 Morbidly obese: >40 The World Health Organization: <18.5= underweight 18.5-25= normal 25-30 = overweight >30= obese Percent Body fat: Minimal fat: men= 5% Women= 8% Below Average: men= 5-15% Women= 14-23% Above average: men=16-25% Women= 24%-32% At risk: men= >25% Women= >32% Genetics vs. Environment *Weight status is more related to genetics than it is to behavior -Familial weight differences: are not significantly different between siblings or twins who live together or are separated early in life. In fact, adopted children exhibit better correlations with their biological parent than with their adoptive parents -The probabilities of lean/obese parents having lean/obese children: Parent Lean Child Obese Child Lean X Lean 90% 10% Lean X Obese 60% 40% Obese X Obese 20% 80% Bouchard conducted studies of 12 pairs of identical twins and had them overeat for 100 days and compared their weight change and visceral fat gain *Findings are that there is a genetic component to weight or fat gain which can be modified by the environment. Combining the results of genetic studies in overweigh and obesity, the contribution is estimated to be: -25% genetic -30% cultural (environment) -45% unknown Theories of weight gain/loss: **Set Point Theory: after puberty, the body’s genes code for a specific number of fat cells in the body Liposuction - # of fat cells return to pre-liposuction over time, even if calories are restricted Caloric Balance Theory: calories in = calories expended to maintain weight. Weight will adjust based on the balance of calories in/ calories expended *Problems with this theory: High Fat Nutrient Intake: In this theory, both the quality of the nutrient intake as well as the way food is consumed contribute to overweight obesity STUDY DONE: *Osci and colleagues randomized rats into four groups. The control group at regular nutritionally balanced rat chow, the Hi-fat group at high-fat rat chow, the hi-sugar group at high sugar rat chow and the fourth group at high fat and sugar. *The control and the high fat/sugar group at more calories than the hi-fat or hi-sugar group. *The control group exhibited the lowest percent fat *All three of the Hi groups exhibited a high percent body fat *The nutrient quality of the food appears to have an influence on weight or fat gain *This means that the caloric balance theory is not always true, you still have to eat well (to some extent, you are what you eat) *Similar patterns can be found in humans. Both obese men and women eat a higher percent of fat than lean men and women (but it’s the opposite for carbohydrates) *Eating patterns may also contribute to overweight and obesity. *In a weight cycling study, Brownell and colleagues exposed rats to a period of overeating followed by a period of dieting, followed by another period of overeating and another period of dieting. They measured how many days it took to gain or lose 130 grams. *Results show it took almost 50 days to gain the 130 grams during the first weight gain cycle. The rats then lost weight before overeating again. For the second weight gain cycle it only took about 10 days. *Then it took about 20 days to lose the 130 grams gained from overeating *The rats overate again, for the second weight loss cycle, it took over 40 days lose the 130 grams CONCLUSIONS: twice as long to lose weight, one-third the time to regain the weight and redistribution to Upper Body Fat Deposits Thermoregulation: *Body temperature is a balance between heat gain and heat loss Heat gain is due: 1. Gain heat from the environment 2. Gain heat from your metabolism (exothermic-produce heat) Energetically, heat loss is due toe four factors: 1. Conduction: heat transfer due to physical contact 2. Convection: heat transfer due to the movement of fluid passed your body 3. Radiation: electromagnetic property of heat transfer 4. Evaporation: heat loss due to changing water to gas (YOU CANNOT GAIN HEAT THROUGH EVAPORATION ONLY LOSE) Mechanism of Heat % of total heat loss at% of total heat loss Loss REST during EXERCISE Convection & 15% 30% Conduction Radiation 70% 10% Evaporation 15% 60% If the air temperature is greater than body temperature, which mechanism becomes unable to “dump” heat form the body – and in fat gains heat from the environment? Convection If the humidity of the air is very high, which mechanism will have a decreased capacity to “dump” heat from the body? Evaporation: less able to evaporate when the humidity is high Which mechanisms of heat loss are GREATLY affected by exercise in water compared to air? Convection and evaporation Which mechanism of heat loss is greatly affected by the wind velocity? Wind velocity an accelerate evaporation **Note that except for exercise in EXTREME environmental conditions, heat loss is affected primarily by the gradient between skin temperature and the environment** What is the ideal environmental condition for endurance exercise? About 50 degrees (spring or fall) What is the ideal environmental condition for a sprint/ power exercise event? About 70-80 degrees you can get more power from warmer muscles Three standard measures of body temperature Core body temperature: typically measured as rectal temperature. Can also be measured as esophageal temperature or tympanic membrane temperature Ingestible wireless thermistor capsules- newest technology Skin body temperature: usually will be a weighted sum of the sites that are measured by thermistors. Not all skin sites will have the same temperature. Control of body temperature: *Thermoreceptors send information to the hypothalamus in the brain. The hypothalamus acts as the body’s thermostat- which has a standard set point *They hypothalamus activates mechanisms that regulate thermoregulatory mechanisms. Physiological thermoregulatory mechanisms: 1. Sweating 2. Vasodilate/ constrict blood to and from extremities (to core) 3. Shiver (when cold, involuntary muscle contractions to create heat and warm body) 4. Non-shivering thermogenesis: regulates hormones to regulate temperature (thyroid hormone) **However, a key thermoregulatory mechanism of the body is behavioral adjustments** Negative physiological effects of exercise in the heat: 1. Redirect blood flow to the skin, away from the muscles 2. Increased plasma volume loss due to sweating 3. Increase in core body temperature, effects certain enzyme function 4. Increased glycogen use rate: so you run out of energy faster 5. Increased heart rate at any workload **Both cooling strategies (sweating and vasodilation) have negative consequences for endurance exercise performance** For each case of cardiovascular response (rectal temp, stroke volume, heart rate, cardiac output) in heat they have to stop exercising sooner. *In heat stroke volume is lower, rectal temp is higher, cardiac output increased but ends earlier, heart rate increased and stop sooner Heat acclimatization: gradual improvement in the body’s ability to eliminate excess body heat during exercise Positive adaptations with heat acclimatization (training in heat) 1. Plasma volume expands (more water is stored) this is the quickest and strongest response (hemoglobin goes down because plasma goes up) 2. Sweating starts earlier in exercise 3. The combination of #1 and #2 means less blood flow is directed away from the muscle to the skin for cooling – more O2 is delivered to the muscle 4. Sweat is more dilute- preserving more of the body’s mineral stores 5. Muscle glycogen use rate declines by 50-60% 6. Body temperature is reduced during exercise (the rise in temp is a lessened) 7. HR at any workload is reduced Heat acclimatization is good: How to do this? -Heat acclimatization only occurs with exercise: simply sitting/living in a hot environment will not work -Exercise, even in a cold environment, promotes a heat acclimatization effect -However, the rate and completeness of heat acclimatization is dependent upon 3 things: 1. Temperature: the hotter the weather the faster you acclimatize 2. Exercise intensity: the more load the faster you see changes 3. Exercise duration: the longer you exercise the quicker you acclimate. Acclimatization: specifics -80% of the acclimatization response is complete in 5-6 days (Cardiovascular adaptations complete within 3-5 days, changes in sweating mechanisms take longer) -Acclimatization response is temperature and humidity specific -Acclimatization is typically complete by 10 days -Approximately 2-3 hours per day of heat and exercise exposure are ideal -Women and men acclimatize at the SAME RATE, however, women depend more on circulatory adaptations (women send more blood to skin instead of sweating), while men depend more on sweating -Training volume and intensity will likely need to be cut back during the acclimatization n period Hydration: sports drinks *Hydration is without a doubt the single most important factor for exercise in the heat *Decline in running velocity with dehydration of about 2% of body weight (3% effect on performance!!) *The easiest way to judge hydration state is to use the “pee test”- the color of urine indicates hydration level A key physiological factor when selecting a fluid or designing a sports drink is: Gastric emptying rate: maximal amount of fluid that can be emptied from the stomach each hour during vigorous exercises (about 800 ml) Maximal body fluid loss each hour during vigorous exercise in the heat (about 2000 ml) *Water empties from the stomach faster *Cold fluids empty faster than hot fluids Gastric emptying rate is slowing when the fluid ingested contains additional substances besides water (10% glucose solution cuts the rate of gastric emptying by 50%) *Glucose polymers (where glucose is linked together to form longer chains) minimize the slowing effect of sugars on gastric emptying *The optimal concentration for sports drinks is about 7-8% (max carbs with minimal emptying effects) Effects of pre-exercise carbohydrate feeding (sport drink) on blood glucose levels during exercise *Exercise itself causes glucose to enter through channels to the muscle *Study gave sugar feeding 45 minutes before exercise -Blood glucose rises but had a big crash at time of exercise and couldn’t exercise as long -High levels of insulin to open channels and exercise opens the channels too so this causes crash once you start exercising because the insulin response goes away *The best time to drink a sports drink is 10 minutes before exercising or one hour before exercising so you don’t have an insulin spike and it wont conflict with exercise Lead sports scientist for Gatorade did a study on pre-exercise ingestion of differing amounts of carbohydrate on subsequent metabolism and cycling performance -65% of vo2max for 40 minute all out time trial -All 3 of the sugar drinks went down and crashed during the steady states, but during the all out time trial with an increase in intensity, blood sugar levels will increase Exercise in the cold: -Because exercise is thermogenic, temperature regulation is less of a concern (this is being able to dump heat is not usually a problem in a cold environment) Health hazards/physiological problems due to exercise in the cold: -Wind chill: increases convective heat loss -Exercise in cold water: because water has a higher specific heat than air, heat loss in water is over 20 times more rapid than heat loss in air of the same temperature. The body will have a negative heat balance (lose heat) being motionless in water colder than 90 degrees F. Ideal temp for swim competitions is because 75-82 deg F -Muscle “warm up”: decreased power, decreased efficiency, increase risk of “pulling” in power events in cold weather -Bronchospasm: Inspiring cold (and dry) air causes some individuals to bronchoconstrict or bronchospasm, which triggers an asthmatic response. Danger of actually “freezing” or damaging lung tissue during exercise in the cold is extremely minimal. (*People with asthma have more issues in cold dry air) Ergogenic aids: an ergogenic aid is any substance, intervention or phenomenon, which enhances performance *Can be pharmacological, nutritional, mechanical, psychological or procedural Performance “optimizing”: seen as legal and ethical and as smart preparation and part of best practices i.e. taking sports drink during a marathon or properly hydrating before an exercise bout is certainly viewed as being appropriate Performance “enhancers”: have the connotation as being illegal and unethical and the enhancement is often viewed as being unnatural Bicarbonate Loading: (competition day ergogenic) What is it? Baking soda How does it work? Increases bodies ability to buffer acid *Beta alanine causes an increase in carnosine (acts like lactic acid buffer) *Only side effect of beta alanine can cause parasthesia (tingling in fingers and extremities) What athletic events is it primarily used for? Swimmers and track and field (all out events that last 1-4 minutes) What energy system does it affect? Glycolytic energy system How do you use it? Dissolve a certain amount in water and drink it How much can it improve performance? 5 second for every 60 seconds of effort (improve 1 second-HUGE) What are the consequences? Osmotic diarrhea (time out when to take it) Legal/ethical? It is not a drug, it is “food” (but some people say its unnatural) Steroids: *Cholesterol= steroid *Allergy medicine= steroid (present in foods and drugs) How does it work? Increases body production of testosterone (anabolic steroid) Helps speed up recovery from high intensity workouts so they could train more What athletic event? More muscle=more power How do you use it? Use in training regularly and have to build up How much can it improve performance? Dependent on dosage (high dose can improve a lot but causes most consequences) What are the consequences? Liver dysfunction, increases cholesterol, heart issues, increase risk of cancer, testosterone levels change (in women causes masculinity, acne psychological effects) *Unethical and illegal Testosterone: works the same way as steroids (has similar effects as anabolic steroids) - You can inject testosterone or use it in a foam or gel - New data shows that testosterone increases muscle mass through activation of mTOR HGH (Human growth hormone): hormone made by pituitary gland to stimulate growth pre puberty -People use it because it speeds up recovery and it’s a potent fat burner -A lot of sprinters use it -Consequences? Acromegaly: facial features increase with an increase in HGH because the hormone remains active in these places causes jaw, ear, nose to grow -Can’t tell the difference between natural and injected so you can’t test for abuse Blood Doping: What is it? Autologous: using your own blood Homologous: using someone else’s blood How does it work? Infuse red blood cells into body to try and increase the O2 carrying capacity and resist fatigue What athletic event? Endurance events (4 minutes and longer) How do you use it? 2 units of blood to get 1 L to increase amount of blood in body about 15-20% Use it the night before or the day of competition How much can it improve performance? Extreme potential in enhancing performance, can improve VO2max by 5% and improves your endurance What are the consequences? Autologous: training will be poor after you take out your blood and before re-injecting it Homologous: could catch disease through other people’s blood *Increase risk of heart attack and stroke because when you blood dope you increase blood viscosity) EPO (erythropoietin): -Hormone made by kidney that tells your bones to increase RBC production -USES Oxidative energy system -Has to be used regularly in training to have an effect Ice Vests: -Minimize core temperature from rising as much -Invented for rowers and Nascar drivers wear them to keep them cool -Use it right before or during competition -What are the consequences? Adds weight Nutritional Ergogenic: *Carbs are extremely important in exercise, when you run out you “hit the wall” -Carbohydrates are the primary fuel source for exercise -Fats can only be used to supplement carbohydrate usage as a fuel (fats burn in a carbohydrate flame) -The body’s glycogen stores are limited, mainly because of weight, about 200g in muscle/ 90 g in liver -Glycogen stores change with training: untrained individuals have enough stored glycogen to last for about 60 min of moderate exercise, trained individuals have enough for about 2-3 hours of moderate exercise. (Typical person uses 75g of glycogen per hour of exercise) -The rate at which glycogen stores are used during exercise is dependent on exercise intensity, physical condition/training state, environmental conditions and pre-exercise diet -Rate of glycogen use is highest at the beginning of exercise Carbohydrate loading: **Carb loading for short duration events is not going to significantly improve performance **For carb loading to work your event should be longer than 90 minutes -Should take place 3-7 days prior to competition -How? Old method (Astrand) and new method (Sherman) Old Method (Astrand): -7 days prior to event: Very long continuous exercise bout to deplete glycogen stores -Next 3-4 days: High protein/low carbohydrate diet. Training is somewhat impaired. You increase a hormone called glycogen synthase, which tells you to store glycogen in muscle and liver -3 days prior to even: Very high % and volume carbohydrate diet New method (Sherman): -7 days prior to event: Possible longer exercise bout -High protein diet is not necessary -3-5 days prior: high % and volume carbohydrate diet (goal of 10g/kg bodyweight/day) Consequences of carbohydrate loading: -Because glycogen is “wet” the extra water weight may make the athlete feel a little heavy on the race day. Some athletes experience diarrhea and or insomnia due to high carb diets Importance of daily high carb diet: Recommendation of 5-7g/kg body wt/day to maintain training Post-exercise “window” for CHO reloading: Rate of glycogen re- synthesis/storage highest within 30 minutes of completion of exercise (lasting longer than 60 min) -Approximately 2 hours after exercise, muscle glycogen synthesis rate is back to normal -Body will naturally store more glycogen than normal 30-60 minutes after exercise so it is really important to get carbs in body after workout within 30 minutes (easiest way would be to drink the carbs) Chocolate milk: post-exercise glycogen storage rate is higher when carbs and proteins are ingested in a 4-1 ration because we are looking for a specifc hormonal response, ideal post workout meal or beverage has this ratio of 4:1 which chocolate milk has) Caffeine: well-known central nervous system stimulant, which can be performance enhancing -From a metabolic standpoint, caffeine also causes the body to release fats into the bloodstream where it can be used as fuel -This allows the athlete to “spare” glycogen use and rely more on fats (glycogen stores last longer and the athlete doesn’t bonk) -The caffeine equivalent of 2-3 cups of coffee approximately 30- 90 minutes prior to the event -The body will preferentially use whatever fuel has been recently ingested as a fuel in the largest quantities. Therefore, athletes who carbohydrate load will NOT preferentially use fats over carbs after caffeine ingestion -This is useful for lesser trained individuals who do not carb load before a prolonged exercise bout -Consequences? “Jitters” *More difficult to exercise on Atkins diet because Atkins diet is a 40% carbs 30% proteins 30% fat diet and athletes generally require a 70% carb diet so therefore exercise tolerance will be limited with less intake of carbs because glycogen will be depleted. Altitude -Hypobaria: where atmospheric pressure is lower than where it’s at sea level (760 mmHg) -Exists at altitude -Hyperbaria: higher atmospheric pressure than normal/sea level -Exists diving (below seal level) -Hypoxia: oxygen content in the blood (or air) is lower than normal (can happen at altitude) -Hyperoxia: higher than normal O2 content in the blood *The higher the altitude the lower the pressure Physiological Variable Response with ACUTE Response with altitude exposure CHRONIC altitude exposure Ventilation Increase Stay increased Blood pH Increase slightly Normalize back to sea level values (7.4) Plasma Volume Decreases Stays decreased (less than acute) Erythropoietin levels Increases usually Back to sea level about 50-400% peaks baseline at 48-72 hours Hemoglobin mass Nothing Increase (typical response after 4 weeks is 5%) Arterial oxygen Decreases slightly Still decreased content Q at rest and submax Same or slightly Same or slightly increased increased Q at max exercise Reduced slightly Reduced slightly SV Decreases because of Same or slightly decrease in plasma reduced volume HR at rest and submax Increase Back to sea level values HR at max exercise Same or slightly Same or slightly decrease decrease Lactate levels (at Increase Decrease (Lactate max) paradox: defies logic of lactate assumption) Muscle fiber size Same Decrease (this is good thing because you decrease diffusion distance) VO2max Decreased Improve but still less than sea level Performance at altitude: ACUTE: -Linear decrease in performance the higher the altitude -For aerobic/endurance events -Although VO2max is a physiological measure and NOT a performance measure, there is a strong correlation between VO2max and aerobic exercise performance (it is decreased at altitude) -Individuals with a high VO2max will have a greater reduction in VO2max at altitude -Highly trained endurance athletes are more susceptible to altitude mediated declines in Vo2max and performance compared to untrained -Special exception for high velocity aerobic events: cycling and speed skating for example because of the decreased air resistance at altitude these athletes will see an improvement in performance -For anaerobic events unless it has to due with fast velocities than typically there is no change in performance at latitude -If the event does involve fast velocities then performance will be improved at altitude For athletes involved in events that include a skill component, the reduced drag at altitude can significantly affect motor skills and task completion Examples: -Ski jumping -Figure skating: the reduced drag at altitude causes a slight over rotation during the spinning jumps Performance at altitude: CHRONIC: -With altitude acclimatization, VO2max and performance at altitude will improve, but will not reach pre-altitude seal level values -A full response typically takes about 2 weeks and doesn’t improve with added time Altitude training for sea level performance: -Some people believe that training at latitude will improve performance at sea level -Increases in the volume of red blood cells do lead to performance improvements -Due to some combination of living at altitude (acclimatization response) and training at altitude (hypoxic training) leads to help performance -Performance can decline after hypoxic training -Most studies show no improvement in performance with living and training at altitude -Recent studies have proposed that athlete should live at altitude to gain increased in the oxygen carrying capacity but should train at low altitude to minimize the negative effects of training hypoxic (“Live high- train low”) Stimulated altitude environments: -Normobaric Hypoxia (normal barometric pressure and hypoxic inspirate) -High-low training is thought to optimize altitude training and minimize the number of people who don’t improve with altitude training -Shows improvement in race time Clinical problems with altitude exposure -Acute mountain sickness: nausea, vomiting, lethargy, headache, insomnia because you are altitudes above 9,000ft it happens because individuals with a low ventilator response to hypoxia build up CO2 in the arteries and tissues -High altitude pulmonary edema (HAPE): at thigh altitudes, the pulmonary arteries respond by constricting. This greatly increases arterial pressure. As a result, fluid can leak out of the pulmonary arteries, into the alveolar space (can be life threatening) -High altitude cerebral edema (HACE): fluid accumulation in the cranial cavity. Occurs at extreme altitudes above 14,000ft
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