Heart disease has been the leading cause of death in people 65 and older for the past 2 decades 37 of all deaths have to do with heart disease The top ve deaths are attributable to deterioration of in the cardiovascular and respiratory systems Top ve in order of most frequent to less frequent Heart disease cancer stroke COPD and pneumonia In the young only physically demanding activities show how a sedentary and t person are different Both young people can work simple life tasks the same way It is not until old age that you can tell the t and sedentary apart by how they perform everyday tasks Aging Effects on The Cardiovascular System The main functions of this system Transporting all substances essential for cellular metabolism Deliver oxygen and nutrients get rid of waste Protect against blood loss via blood clotting Protect body from foreign pathogens Cooling the body like a cooling system does with a car Heart Structure and Control When resting the cardiovascular system stays within the same parameters However in older adults cardiovascular response to exercise is reduced Differences between the young and old are see in cardiovascular performance but usually there is lack of acknowledgement interactions between age disease and activity In older adults there is increased thickening of the walls of the walls of blood vessels tunica intima and left ventricle increased stiffness in the aorta and arterial tree and increase in size of the left atrial chamber of the heart There are some studies that show a smaller number of cells in the heart but they become larger which affects the contractility of the heart Thickening of the vessel walls can be a strong predictor of stroke and cardiovascular disease The left ventricle pushes blood to all over your body except the lungs and increases in wall thickness by 30 between the ages of 25 and 80 Could happen since there is an increase in systolic pressure over the years Resting levels are not affected by wall thickening of the ventricle Increase in systolic pressure is also a result of the aorta and arterial tree becoming stiffer and less compliant In sedentary people between the ages of 25 and 75 there was a 40 50 decrease in carotid artery compliance Small vessels like the arterioles become less responsive to hormonal cues for dilation and so remain constricted All of these things lead to hypertension Regardless of these changes in the body a non diseased person has adequate heart function for light work and rest Yet atherosclerosis does all of the above and makes the cardiovascular system work under high amounts of stress in even the lightest of work Communication between the cardiovascular system and the nervous system happens through the PNS and SNS of the ANS PNS will release Ach into the pacemaker of the heart to slow it down Norepinephrine is released by the SNS to make HR go up and the heart to contract harder SNS also makes the adrenal medulla to release norepinephrine and epinephrine Note In older people it is only during sub maximal exercise that there are higher levels of NE than in younger people On the other hand in older people levels of EPI are higher under all conditions The older heart does not respond to hormones as well as the young heart so at older ages the maximum heart rates are not the same These are one of the rst changes seen while aging in people that are cardiovascular disease free Total peripheral resistance Ease at which blood can ow from arterioles into capillaries Enlarging the radius means a decrease in resistance There is a 1 increase in TPR each year in healthy people Controlled by receptors Alpha receptors are found in the smooth muscle of the walls of the arterial tree and a few in the heart Controlled by the contraction of smooth muscles Beta receptors are found in all the same areas causes the smooth muscles to relax and dilate With age the smooth muscle becomes less sensitive since there is a decrease in beta receptors thus the body leans towards being vasoconstricted more frequently AKA more frequently there is high TPR Postural Hypotension Age related change in the neural control of the arterial tree Result of loss of response to homeostatic re exes When older people stand up too fast the barore exors that assure blood gets to vital organs and the brain by increasing heart rate do not respond as well Thus not enough blood is bumped up and there are symptoms such as dizziness and confusion 20 30 of the young old and 30 50 of those older than 75 Heart Function The heart is a huge player when it comes to quality of life Heart Rate Maximum heart rate during exercise decreases by 5 10 beats per decade and no amount of training can slow this down As explained previously by the lack of beta receptors Estimated maximal heart rate of older people is used frequently since most of the time older people aren t in conditions to exercise to that point You can estimate it by the equation 220 age But for healthy adults over 40 the equations is 208 0 7 x age since the rst equation usually underestimates it for them SV is the amount of blood in mL that is pumped from the heart with each beat If more blood is returned to the heart from the peripheral circulation then it will react by stretching and contracting more vigorously Responds to increase in work demands One study showed that the SV decreased with age but the subjects weren t screened for disease so ignore that Stroke Volume Cardiac Output Q is the total amount of blood ejected from each ventricle of the heart in one minute expressed in L per minute In exercise it represents the ability of the cardiovascular system to deliver oxygen and nutrient s to the exercising muscles Relative to body size divide Q by body size to get the cardiac index Maximum cardiac output total amount of blood that can be ejected fro one contraction x the maximum heart rate 25 decrease of this output is seen in older adults Using the O2 that is Circulated The arteriovenous O2 Difference O2 diffuses out of the capillaries through the membrane and into active tissue O2 is taken in and CO2 is exerted when food is being metabolized into energy Blood that goes into the veins has less oxygen but still has oxygen The difference between the amount of O2 in the capillary beds and the veins in the arteriovenous O2 difference IT indicates how much O2 is being taken up At rest the difference is 5mL There is a decrease in this difference at rest as you age At 65 it is 20 30 lower than a 25yo