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Belisena Hall 1, Brooke Mitchell 1, Kate Derouchie 1 , Victoria Mitchell 2
1 Department of Psychology, Clarkson University, Potsdam, New York 13699
2 Department of Biology, Clarkson University, Potsdam, New York 13699
Abstract
During strenuous exercise, people often hold their breath. Many people believe when lifting heavy weights, holding your breath can provide momentum and trunk stabilization, however it can be very dangerous9. It limits the amount of oxygen entering the body, causing the body to be in a lower oxygen state. Additionally, blood pressure can rapidly increase. We anticipate that this oxygen-deprived state will lead to decreased exercise performance. We will examine the effects of restricted breathing during exercise to see if it affects performance. Subjects will perform jumping jacks while holding their breath and their performance will be compared to them performing the same activity while actively breathing. Blood pressure, heart rate, reaction times, and pulse oximetry before, and after the exercise will be measured and compared between each participant.
Introduction
There is always a high demand for oxygen in tissues. Its role is essential to keep muscles functioning. In fact, the cardiorespiratory systems ultimate purpose is to deliver oxygen to tissues while removing carbon dioxide that is produced. So how does the frequency of breathing during exercise affect the body? There are three terms that describe the level of tissue oxygenation. The first level is normal, which indicates that PO2 is greater than the critical amount of PO2, which would be 75-100 mm Hg, necessary to generate maximum levels of ATP. The second level is hypoxia which occurs when there is an insufficient level of oxygen, 60 mm Hg, causing mitochondria to produce ATP below the maximal rate. Lastly anoxia occurs when there is a total lack of oxygen in the tissue, which causes ATP production to cease7. During exercise the rate of cellular respiration increases to provide more ATP for the muscles to contract. Carbon dioxide is produced by cellular respiration and must be removed via internal respiration. Internal respiration occurs at the tissue level and exchanges oxygen and carbon dioxide based on partial pressures. This blood is brought to the lungs where it becomes oxygenated once again during external respiration. Changing the rate of respiration can increase or decrease the level of oxygen intake. During exercise, there is a higher demand for oxygen in order to replenish the working muscles. A common mistake people make while exercising is not breathing properly. They tend to hold their breath or decrease respiration rate, which results in hemodynamic effects1. Some other effects include an imbalance of nutrients, hormones, oxygen and carbon dioxide levels, pH, osmotic pressure and temperature. This is all ultimately caused by a change in the amount of blood flowing through the tissues. The effects resulting from a change in the blood flow from inadequate breathing during exercise can be analyzed by examining individuals’ hemodynamic parameters after performing a physical activity when they hold their breath versus not holding their breath. Prior research has shown that holding your breath with no exercise has little effect on heart rate, but both systolic and diastolic blood pressure increased and the oxygen saturation decreased2. Another study showed that exercising with restricted or obstructed breathing causes very rapid and shallow breaths, which was disadvantageous3.
The frequency of breathing is not the only thing that affects the body. The type of exercise someone performs can also be a contributing factor. Having someone perform an intense cardio exercise could have variable differences compared to lifting weights. Cells contain mitochondria which use oxygen to create ATP, which then fuels the muscle contractions. Slow twitch fibers can sustain energy for longer periods of time, but with less force, therefore would be used in activities such as cardio. Slow- twitch fibers are recruited first when the muscle contracts, but if they cannot generate enough force for the activity, fast-twitch fibers are recruited. Fast-twitch fibers have a high threshold and will be activated if the slow-twitch fibers cannot handle the threshold; so they would likely be activated during weight lifting. A study showed that increasing dynamic exercise loads raised participants blood pressure, however; by increasing the participants breathing frequency their blood pressure returned to normal4. During non-hypoxic conditions, one’s reaction should be relatively normal, .14 to .16 seconds, whereas under hypoxic conditions it is expected to increase, variably8. However, any form of exercise should considerably shorten the amount of time between someone inspiring and expiring5. Every exercise type requires different muscles, types of respiration, and different amounts of energy. In a study done by Bechbache and Colleagues5 , the breathing rates of three parameters hypoxia, anxiety and exercise alone were measured and it was found that those who were able to match their breathing rate to their exercise pattern were better able to control their inspiratory and exspiratory times, despite what parameter they were in. In contrast, those who had difficulty matching their breathing rate and exercise pattern had a range from low to high inspiratory and exspiratory times.
In order to measure the effects of restricted breathing on exercise performance, we will have our participants perform a specific exercise at two separate times. We will have each participant perform the same exercises in order to most accurately determine how breathing truly affects physical performance. Since we are analyzing restricted breathing, it will be most effective to have participants do exercises such as jumping jacks, high knees, or using a step to perform aerobic tasks. However, each participant will perform the specified activity twice, once after holding their breath for 30 seconds and then a second time while actively breathing. We hypothesize that after participants hold their breath for 30 seconds and then perform 45 seconds of jumping jacks that heart rate and reaction times will increase, and blood pressure, and pulse oximetry will decrease. When the participants breathe normally before doing jumping jacks for 45 seconds, we predict an increased heart rate, decreased blood pressure, and similar reaction times and pulse oximetry.
Methods
Study population
The population consisted of 19 healthy college-aged students of varying race, gender identity and physical ability. Each individual was asked to perform the same physical activity twice, once with restricted breathing and once while actively breathing. The restrictive breathing parameter was holding their breath for 30 seconds before exercise and the actively breathing parameter was not holding their breath before exercise.
In order to ensure accuracy, each participant had all four measures recorded before and after performing the 45 seconds of jumping jacks. Participants were connected to a pulse oximeter, pulse transducer, and automatic blood pressure cuff to measure oxygen saturation of the blood, heart rate, and blood pressure respectively. Reaction time to an auditory stimulus was measured with a push button switch and macro machine. Also, every participant performed the experiment in the same order to ensure greater accuracy.
Protocol
Please note that for every procedure in this experiment excluding blood pressure, the PowerLab system was utilized. Labchart software was also used to analyze the data. All graphs and tests run were done on the Prism system. Before and after exercising we controlled the individual’s breathing by having them take a eupnea breath rather than a hyperpnea breath to avoid an increased amount of oxygen within the individual’s blood.
Procedure 1 (Blood Pressure)
An automatic blood pressure cuff was used within this experiment. The cuff was a universal size and was meant for placement on the wrist. Once placed the participant was asked to keep their elbow on their thigh and tilted upwards to be more level with the heart. The automatic cuff calculated the blood pressure within about 30 seconds and then just to make sure it was accurate, a non-automatic appropriately sized cuff was used for comparison. Once checked off as accurate the blood pressure from the automatic cuff was recorded. This was done before and after the volunteer had completed each exercise. The blood pressure was taken approximately 90 seconds after the exercise was completed.
Procedure 2 (Push button/Macro)
The push button switch was connected to Input 2 while the finger pulse transducer was connected to Input 3 on the front of the panel on the PowerLab. The hardware must be connected before turning on and opening the settings file. The pulse transducer was secured and the volunteer was instructed to click the push button as soon as they were given an auditory cue. The auditory cue was from a macro that produced a tone regularly. The time lapse from when the stimulus appeared to when the subject pressed the push button was recorded as the subject’s reaction time. There was no pattern to when the auditory cue was being given so as to eliminate any confounds. This part of the experiment took place until there were five responses recorded from each individual. The responses were then averaged before the standard deviation was taken. The averages before and after for each individual were compared graphically and their statistical difference was analyzed using a t-test. This was done before and after the volunteer completed the exercise. The reaction time was measured right before exercise and approximately a minute and a half after the exercise.
Procedure 3 (Pulse Transducer/Heart rate)
The finger pulse transducer was connected to Input 2 on the PowerLab. The transducer is placed on the pad of the middle finger with Velcro to secure it tightly. If too loose, a reading will be difficult to record. The volunteer will be facing away from the monitor at all times and their hand will be relaxed without resting the pulse transducer on anything. The transducer will record for approximately 30 seconds to allow for a few full wave forms to be present. The cyclic measurements feature within LabChart was used to automatically calculate the heart rate. The pulse transducer was used right before the exercise as well as about 45 seconds after the exercise was completed.
Procedure 4 (Pulse Oximetry)
The oximeter was placed on the middle finger of one of the individual's hands. The laser should be on the pad of the finger, not the nail. The oximeter was then connected to the oximeter pod and then the PowerLab, Input 1. Our created settings file was then opened while the volunteer was facing away from the monitor with their hand flat and still. Their pulse oximetry was then recorded for one minute to allow for an evening out. This was measured right before and approximately 45 seconds after the volunteer completed the exercise.
Results
All 19 participants were subjected to the same exact parameters, including the order in which the experiment was done. The four parameters were measured on each participant before and after completing the exercises for each condition. We calculated the participants’ total change from their baseline for each parameter and condition.The graphs showing the comparisons for heart rate(a), blood pressure(b), and pulse oximetry(c) can be found in
Figure 1. The comparison graph for the reaction time parameter can be found in
Figure 2.