Lab report and must have the sensors to check heart rate to do this lab.
Effect of Coughing on Heart Rate
Involuntary coughing is the result of irritation of special sensory nerves in the respiratory tract.
This helps to clear potentially damaging substances from the lungs (water, foreign bodies, dust,
infection, mucous, etc.). Coughing can be more deleterious than helpful, causing discomfort,
preventing sleep, or leading, in some cases, to dizziness or loss of consciousness (known as
The physiologic effects resulting from a cough are numerous. There is marked increase in
intrathoracic pressure just prior to expulsion of air. When blood pressure is normal, this leads to
a decrease in venous return to the right side of the heart and a decrease in cardiac output. On the
other hand, a cough-induced increase in intrathoracic pressure may provide a form of internal
cardiopulmonary resuscitation in a heart attack victim whose blood pressure is falling
dangerously low. In this case, coughing can be as effective as the external chest compressions of
CPR in raising blood pressure and providing better blood circulation to vital tissues.
Coughing, and the resulting wide fluctuations in intrathoracic pressure it produces, causes reflex
stimulation of the autonomic nervous system. The sympathetic nervous system is an activating
system, preparing the body for a flight or fight response by increasing heart rate and blood
pressure. The parasympathetic nervous system acts through the vagus nerve to slow the heart and
to lower blood pressure. Both the sympathetic and parasympathetic systems may be stimulated or
inhibited by physiologic stimuli or medications.
The following table shows potential heart rate response to stimulation or inhibition of the
sympathetic or parasympathetic nervous systems:
Branch of Autonomic
Heart Rate Response to
Sympathetic ? ?
Parasympathetic ? ?
In this experiment, you will observe the response of heart rate to coughing, and correlate this
response to activity in the autonomic nervous systems.
Important: Do not attempt this experiment if you suffer from asthma or any condition that may
be aggravated by repeated coughing
DATA ANALYSIS FOR LAB REPORT
1. In what direction did your heart rate change in this experiment? According to the table in the
Introduction, what are the possible explanations for this change?
2. There are medications that can selectively block the action of either sympathetic or
parasympathetic influences on the heart. How could such medications be used to determine
which of these systems is responsible for a change in heart rate such as was seen in this
3. Compare the response and recovery times recorded in Table 1. List possible survival
advantages of the differences you see.
4. The parasympathetic and sympathetic nerve supplies are severed during heart transplantation
and are not surgically repaired. Would a heart transplant recipients heart rate change with
coughing (or with a severe fright)?
5. You are in a remote location and a member of your party complains of chest pain and
dizziness. You find that his pulse is 35 bpm. You immediately call 911 and are told that it
will take 15 minutes for the helicopter to arrive. You know that CPR should not be performed
on conscious individuals. Drawing from the knowledge you have gained from this
experiment, what might be done to improve your patients pulse and blood pressure?
6. Perform the experiment with different coughing frequencies and intensities.