The physiological changes when exercising

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1. Include your data sheet

Answer: The below figure shows the data sheet for both subjects used in our experiment

Figure 1: Data sheet for subject 1

Figure 2: Data sheet for subject two

2. Whatis oxygen debt?How do sprinters pay back their oxygen debt?


When the sprinter undergoes short intense exercise, blood vessels dilate leading to the increase in the blood flow. As we all know blood plays an important role in transportation of oxygen and carbon dioxide throughout the body. Thus as the blood flow increases the rate at which muscles receives the oxygen also increases. When the sprinter undergoes the intense physical activity for a short time aerobic respiration takes place[1]. But as the strenuous activity increases aerobic respiration can't keep up with the oxygen demands and fails produceneeded ATP.Therefore as the strenuous physical activity increases anaerobic respiration generates energy for the muscles by converting pyruvic acid into lactic acid. Lactic acid generated in this process causes fatigue to the subject and also cramps. As the percentage of the lactic acid increases the pH level of the blood also increases and it becomes more acidic. Therefore to avoid those damages, lactic acid is converted into carbon dioxide and water. This process is called oxidation reaction which requires oxygen. Thus after the exercise sprinters inhale extra amount of oxygen for the oxidation reaction. The extra amount of oxygen required for the above oxidative process is called oxygen debt. Generally sprinters undergo deep inhaling process after long strenuous workouts which results in the restoration of the oxygen debt. This process continues until the lactic acid generated by the anaerobic system is converted to carbon dioxide and water. As the result generation of the additional carbon dioxide, the sprinter exhale extensively to reach the optimum levels. Thus due to continuous deep inhaling and exhaling the sprinter pay back for their oxygen debt. Excess Post exercise Oxygen Consumption (EPOC) is the recovery period where there is excessive amount of oxygen being inhaled[2].

3.Comparechanges in skin temperature before, during & after exercise. Explain the physiological basis of the observed changes.


Whenasubjectgoesthroughaprolongedexercisesthebodytemperatureincreases proportionallytotheamountofexercisesdone.Thechemicalreactionsofburningfuelssuchas fatsandcarbohydrates provides necessary energies for muscles which are used intensively during exercise. Exercising muscles play a huge role in production of excess heat leading to the rise in the body's core temperature and part of the body's heat is also generated by various metabolisms. The hypothalamus in the brain monitors the body's the core temperatures, therefore as the body temperature increases the hypothalamus takes necessary steps to reduce the body's temperature and as the body's temperature decreases hypothalamus takes necessary steps in increasing the body's temperature. One of the main process used for reduction of body temperature is generating sweat. Blood vessels near the surface of the skin dilate and various glands present in the skin secrete sweat as necessary precautionary steps in reduction of the temperature.

After comparing the above the theory with our data we can observe that, when resting the subjects body temperature is around 91.3 F. The subjects core body temperature increases during short burst of exercises, but the amount of the temperature increase depends on the amount strenuous activity. After exercises, the subjects relative body temperature has decreased 83.96. That is due to the heat dissipation process employed by hypothalamus, where it increases blood flow to the skin, stimulating glands in the secretion of sweat.

4. Using the data made available to you all on Blackboard,describe timing & type of physiological changes observedin:

(i)ECG &Heart Rate:


The process of blood travelling through the heart is achieved by the process contraction and relaxation of the heart. Heartbeat is caused by alternating contractions and relaxations of the heart muscles and the term heart rate gives the number of heart beats per minute (BPM). The normal heart rate of an adult is around 60-100 heart beats per minute. Heart rate of the subject varies from time to time depending on that particular activity and heart rate varies from subject to subject for the same activity. Generally the heart rate increases linearly with the amount of strenuous activity undergone by the subject, that is because as the activity of the muscles increases the amount of energy required by the muscles also increases. Therefore to meet the needs of the muscle the heart needs to pump more amount of blood which is accomplished by increasing the number of heart beats which increases the amount of stoke volume.

In this experiment we first calculated the heart rate of the subject while in a relaxed state i.e. the baseline state. Then the subject undergoes strenuous activity and the mean heart rate is calculated. The heart rate of the subjects has been recorded for a time interval of 3 minutes for baseline and 3 minutes for running. By analyzing the gathered data we can see that the heart rates of the collective subjects increases after running compared to that of while they are seating in a relaxed state. That is because subjects heart rates are increased to match the energy needs of their muscles. In principle subjects who exercise will have better heart function than subjects who don't i.e. athletic subjects have lower heart rate compared to that of the non athletic subjects. The heart of the athletic subjects pumps more blood for one contractions, therefore it pumps the required amount blood in a less number of beats while the same tasks may take up more beats for non athletic subjects. From the provided data sheets the heart rates of the majority of the subjects tend to follow the trend where the heart rate increases after exercises. But couple of subjects heart rate are lower after exercise. This may be due to the fact that these subjects may be athletic and their heart function may be better than others. But from the provided data we couldn't justify this conclusion. So the data of the that particular subjects have been excluded. The two subjects data that are excluded are: subject 2 from group 1 and subject 1 from group 5

(ii)Breathing Rate


Respiratory rate of a human body can be defined as the number of breaths taken per minute.

We can calculate the number of breaths per minute by calculating the number of times the chest expands and contracts. Experimentally, to calculate the respiratory rate the subjects are asked to breathe into the transducers. The breathing rate of the subjects has been recorded for a time interval of 3 minutes for baseline and 3 minutes for running. Thus in the process of requiring more amount of oxygen to be inhaled the respiratory rate increases. Respiratory rate also increases to exhale the amount of carbon dioxide generated by the muscles and tissues. For some cases the respiratory rate will be lower for subjects after exercising because of the athletic abilities of the subject. Other factors involving in the reduction of respiratory rate is high tidal volume or low blood pressure. Human body also tries to produce energy through the anaerobic respiration. In this system muscle generates the required energy without the increasing the intake of oxygen but this process leads to production of lactic acid which is harmful to the body and this process is mainly used when the body undergoes strenuous activities for longer period of time. Since the subject has undergone intense physical activity for a short period of time energy is generated by increasing the amount of oxygen intake by aerobic respiration.

From the given data, the mean of the baseline's breathing rate i.e. when the subject's breathing rate when is relaxed as much as possible calculated. When the subject undergoes through short intense exercises the mean the breathing rate are also calculated. By analyzing the data majority of the subjects respiration rate has increased as their strenuous activity increases. This leads to the fact that subjects breathe excess of oxygen to provide source of energy to their muscle. But for than couple of subjects the respiratory rate has lowered after exercises. As stated earlier this may be because of the athletic nature of the subject or they must be having higher tidal volume or their blood pressure was comparatively low. The data sheets used for observation provided no such information regarding those factors. Therefore we can't come to a specific conclusion to justify their decrease in the respiratory rates. Therefore the data of group 3, subject 1 from group 6 have been excluded.

(iv) Temperature:


The temperature of the skin of the subject depends on the time of the day and the activity of the subject. The temperature of the subjects has been recorded for a time interval of 3 minutes for baseline and 3 minutes for running. During exercises body temperature increases rapidly because of intense muscle activity. To reduce the high temperature rise the blood vessels are dilated in the skin which results in the secretion of sweat through skin pores. This mechanism is initiated by the hypothalamus and the process of regulation of the bodies temperature is called as thermoregulation. Hence when the body's core temperature increases during the exercise, hypothalamus plays a vital part in reduction of the temperature through evaporation i.e. secretion of sweat through sweat on skin which is evaporated and produced heat is cooled off.

From the given data the mean of the skin temperature of the subject in a relaxed state is calculated. After subject undergoing a vigorous exercises the recorded change in the temperature are noted and its respective means are calculated. After comparing the means of the different subject we can see that majority of the subjects skin temperature decreases after strenuous exercises. This is because as the amount of activity increases muscles produce even more heat which results in the increase in the temperature of blood. This increase in the temperature of the blood produces increased sweat and ultimately evaporates on the skin and the produced heat during the activity is cooled off. The skin temperature after exercises seems to increase for couple of subjects and this may be because of various factors such of time of exercise, the intensity of the exercise. Since a subjects skin temperature may vary depending on these factors. Since we are not provided with any information regarding these above factors we are excluding the data of subject 1 from group 6 and subject 2 from group 10.


[1]Sharon A. Plowman; Denise L. Smith (1 June 2007). Exercise Physiology for Health, Fitness, and Performance. Lippincott Williams & Wilkins. p.61.ISBN978-0-7817-8406-1. Retrieved 13 October 2011.

[2] Schmidt, Wilfred Daniel (1992). The effects of aerobic and anaerobic exercise on resting metabolic rate, thermic effect of a meal, and excess postexercise oxygen consumption. Ph.D. dissertation, Purdue University, United States -- Indiana. Retrieved March 30, 2011, from Dissertations & Theses: Full Text.(Publication No. AAT 9301378).