Anatomey and physiology
Regulation of the cardiovascular system by examining changes in heart rate
Prepared for Dr. Isabelle Lys
Lecturer of SBI171 Anatomy &Physiology
Charles Darwin University
Summer Semester 2012-2013
Introduction
Every day the human body is involved in various tasks which can alter a person’s heart rate. Some internal and external factors that contribute to changes in HR are thermo-regulatory changes, diurnal changes and sudden postural changes, which are among others such as the Autonomic Nervous system, circulating chemicals, position, exercise, emotional state, gender, age and baroreceptor reflex (Waugh & Grant 2010).
During a recent research Armstrong, Kenny, Green and Seely (2011) discovered slight diurnal changes in heart rate in the healthy young adult participants. Twenty four adults were monitored over a period of 48 hours to assess their heart rates during morning, afternoon and evening. They recorded minimal increase during the evening hours of 0.5%.
In addition to diurnal changes, postural changes also have a large impact on heart rate as Koyama, Asahina, Honma, Arai and Hattori (2008) found in a research about the 'Altered Heart Rate Control in Response to Postural Change in Patients with Machado–Joseph Disease ' (a common type of autosomal dominant hereditary spinocerebellar degeneration), that there were changes in MJD patients as well as those not affected by MJD. Furthermore a study into how postural changes influence heart rate variability showed that there was a significant difference in HR in sudden postural changes such as sitting to standing and lying to standing (Chen et al. 2011).
Another point that will have an impact on HR, according to Robertson (2012), is thermo-regulatory changes. Waugh and Grant (2010) also support this stating that the heart rate will rise and fall with body temperature changes. Body temperature is regulated by the hypothalamus which is alerted to changes in temperature by
Prepared for Dr. Isabelle Lys
Lecturer of SBI171 Anatomy &Physiology
Charles Darwin University
Summer Semester 2012-2013
Introduction
Every day the human body is involved in various tasks which can alter a person’s heart rate. Some internal and external factors that contribute to changes in HR are thermo-regulatory changes, diurnal changes and sudden postural changes, which are among others such as the Autonomic Nervous system, circulating chemicals, position, exercise, emotional state, gender, age and baroreceptor reflex (Waugh & Grant 2010).
During a recent research Armstrong, Kenny, Green and Seely (2011) discovered slight diurnal changes in heart rate in the healthy young adult participants. Twenty four adults were monitored over a period of 48 hours to assess their heart rates during morning, afternoon and evening. They recorded minimal increase during the evening hours of 0.5%.
In addition to diurnal changes, postural changes also have a large impact on heart rate as Koyama, Asahina, Honma, Arai and Hattori (2008) found in a research about the 'Altered Heart Rate Control in Response to Postural Change in Patients with Machado–Joseph Disease ' (a common type of autosomal dominant hereditary spinocerebellar degeneration), that there were changes in MJD patients as well as those not affected by MJD. Furthermore a study into how postural changes influence heart rate variability showed that there was a significant difference in HR in sudden postural changes such as sitting to standing and lying to standing (Chen et al. 2011).
Another point that will have an impact on HR, according to Robertson (2012), is thermo-regulatory changes. Waugh and Grant (2010) also support this stating that the heart rate will rise and fall with body temperature changes. Body temperature is regulated by the hypothalamus which is alerted to changes in temperature by
References: Waugh, A & Grant, A, 2010, 'Ross and Wilson Anatomy and physiology in health and Illness 11th Edition ', Elsevier Limited, Sydney, Australia