Exercise Physiology PDF

Exercise physiology  Study the physiology of body systems during stress ( exercise )  1, the energetics of exercise. 2, the role of physiological systems during exercise. 3, factors contributing to fitness and performance. 4, the influence of exercise in health and disease.. principle H...

Exercise physiology  Study the physiology of body systems during stress ( exercise )  1, the energetics of exercise. 2, the role of physiological systems during exercise. 3, factors contributing to fitness and performance. 4, the influence of exercise in health and disease.. principle Hemostasis : defined as the tendency of the body to maintain a stable internal environment for cells by narrowly regulating critical variables such as pH or acid base balance, oxygen tension, blood glucose concentration, body temperature,  any disruption to optimal homeostatic conditions will elicit multiple regulatory responses by the body In an attempt to bring disrupted variables back to normal levels.. example , when you ascend the high altitude, due to the low oxygen pressure in the inspired air, oxygen levels in your blood drop below desired levels. As a result, the nervous, endocrine, cardiovascular and respiratory systems, makes adjustments in an attempt to compensate for this disruption in homeostasis  engaging in physical exercise is a very powerful disruptor of normal resting homeostasis. The more intense the exercise bout, the greater the disruption in homeostasis. The muscles and blood can become more acidic. Blood oxygen and glucose levels must be regulated to prevent them from falling below normal levels. Body temperature increases activating thermal regulators processes.  adjustments the body must make in response to the stress imposed by a single bout of exercise. many of the systems and tissues that must respond and adjust to exercise. The brain, the lungs the respiratory system, heart and blood vessels, the cardio vascular system, muscles, kidney, liver etc., are most respond.  the major components of the cardio vascular system. In order to ensure that the proper amounts of oxygen and nutrients are being delivered to the working muscles. The heart must pump more forcefully the blood vessels to the muscles must dilate to increase local blood flow. The nervous and endocrine systems are the major regulators involved, responsible for the increase in both heart rate and thereby increasing cardiac output and the pumping capacity of the heart. circulating hormones and local factors cause the blood vessels in the muscles to dilate. The nervous system also redirects or shuns blood away from less critical tissues such as the stomach, to the working muscles.  these cardiovascular adjustments ensure that the muscles are receiving adequate blood flow to support their energetic needs. The overload principle , defined here, provides the underlying validation for all training adaptations associated with both endurance and strength training. As stated, if you habitually overload a system it will respond and adapt.  Basically, when you engage in physical activity, the stress imposed by a single bout of exercise elicits an immediate or an acute response by the body, as already discussed with homeostatic disruption. However, if you exercise three to five times a week for several months, the body will make long-term or chronic adaptations to the repeated stress of regular exercise. An example of the overload principle is shown here. In response to weeks and months of endurance training, a classic chronic adaptation is an increase in mitochondrial number, and oxidative capacity in skeletal muscle. The primary signal shown here, are activated acutely during exercise. After weeks of being repeatedly activated, chronic adaptations are made in the pathway responsible for mitochondrial biogenesis, thereby increasing their numbers. This is just one example of the many long term training adaptations elicited from the overload principle. Specificity principle It states that only the system or body part repeatedly stressed will adapt to chronic overload. An example of the specificity principle is given here. When you do bench presses for weeks and months, only the chest muscles recruited will show improvements in strength. Other muscle groups not involved will show no training adaptations. cardiovascular system is only marginally recruited during strength training, it will show little to no long term adaptations. Thus the overload principle will only apply to the system or body part used while exercising. The principle of reversibility whereas overloading will result in training adaptations, inactivity, or detraining, will result in a return to baseline, or pre-training levels. This relates to the use it or lose it expression, which is commonly stated. when the chronic stimulus for regular training has been removed, any adaptations made during training will eventually return to baseline or pre-training levels.  Such a response is typical when someone will stop training due to illness or injury. Shown here is a classic example of the reversibility principle. Previously, sedentary individuals were endurance trained for eight weeks. The standard markers for endurance training were measured. These include markers of mitochondrial oxidative capacity mentioned previously and maximal oxygen uptake or VOT max. As can be seen, as per the overload principle, eight weeks of endurance training result in an increases in all of these variables.  When individuals stopped all training for a period of six weeks, notice mitochondrial oxidative capacity rapidly return to pre-training values, while maximal oxygen uptake had a more gradual decline. The principle of individuality relates to the genetic or hereditary component of training adaptations. It states that while the physiological responses to a particular stimulus ar largely predictable, the precise responses and adaptations will vary among individuals.  if we were to initiate an endurance training program on two individuals, who are the same age, sex, and fitness level, we can predict the directions of training adaptations, but the magnitude will likely differ.  Based upon genetic characteristics, one individual maybe more responsive to the training stimulus than the other and demonstrate larger increase in such variables as mitochondrial oxidative capacity and maximal oxygen uptake. Identical twins, who have similar genetic material, their response to a training program would be more uniform than two unrelated individuals. In summary, the body's responses to a single bout of exercise are governed by the principle of homeostasis.  Training adaptations, both for health and performance, are influenced by the principles : the overload, specificity, reversibility, individuality. the energetics of exercise the amount of energy expended during a single bout of exercise. useful for various reasons, including :- determine the energy cost for a wide range of physical activities caloric expenditure for weight control, type of fuel or substrate being used by the muscles during exercise. calorimetry which is a technique used to measure an individual's energy expenditure and metabolic rate during exercise as the measurement of heat production, usually measured in units of calories.  all metabolic processes eventually result in heat production, such as a skeletal muscle during a contraction,  estimate an individual's metabolic rate by measuring the rate of heat production. The actual measurement of heat production by the body is termed "Direct Calorimetry",  the most common method for estimating one's metabolic rate, specifically, by the measurement of oxygen consumption. Indirect calorimetry  The rate of oxygen consumption is indicated by V̇O2, the V indicates the volume of oxygen and the dot over the V implies a rate, milliliters of oxygen consumed for a minute.  the individual must complete a graded exercise test to exhaustion. This is generally done on a treadmill or bicycle ergometer. This test begins at a very easy workload. Afterwards, the intensity is gradually increased every two to three minutes until the individual fatigues and can go no further. Oxygen consumption is measured at the end of each stage and plotted against workload. VO2max oxygen consumption does not significantly increase despite the increased workload, indicating the individual has reached his or her maximum rate of oxygen consumption or V̇O2 max.  regular endurance training is an increase in one's V̇O2 max. The reason for this increase relates to improvements in oxygen delivery, thus cardiovascular adaptations, as well as improvements in muscle mitochondrial oxygen utilization.  a second feature of indirect calorimetry is that it allows us to measure the amount or volume of carbon dioxide produced by the body. to calculate the respiratory exchange ratio  This ratio is simply the volume of carbon dioxide produced divided by the volume of oxygen consumed. This ratio is very useful as it provides valuable information on the type of fuel or substrate being used by the muscles during exercise. For example, if you are burning pure fat your respiratory exchange ratio will be 0.70. If you are burning pure carbohydrate your respiratory exchange ratio will be 1.0.  Endurance training will result in an increase in maximal oxygen consumption.  Respiratory exchange ratio can provide an indication of the type of fuel used by the muscles during exercise 0.7 fat 1.0 carb Vo2 max factor Heredity , genetic 20 % vo2 max , 50% maximum haert rat, 70% physical activity Age Childern same until age 12y Sex Differnce 15-20% body composition , HB concentration Body size Training status Type of exercise , tredmill, bicycle Type of muscle fiber used during exercise Slow oxidative fiber -- highest oxygen consumption Altitude Low o2 pressure in atmosphere --- low arterial blood pressure -- low oxygen consumption Temperature High temp ---- high o2 consumption  measuring the amount of energy expended during a single bout of exercise. This is useful for various reasons, including 1. determine the energy cost for a wide range of physical activities, 2-caloric expenditure for weight control, and 2. type of fuel or substrate being used by the muscles during exercise.