©2019 by  Sun Scientific Corporation. & Taiwan Scientific  Corporation

Clinical Applications

Executive summary
  • Case #1: Tachycardia (Fast Heart Rate)

  • Case #2: Bradycardia (Slow Heart Rate)

  • Case #3: (a)Arrhythmia - Atrial Fibrillation (AF) (b) Ventricular Premature Contraction (VPC)

  • Case #4: Pulse Alternans

  • Case #5: Dialysis 

  • Case #6:  Cancer (Esophageal)

  • Case #7:  Depression / Anxiety

  • Case #8: Diabetes

  • Case #9: Deep Breathing / Relaxation Biofeedback

  • Case #10: Faint / Dizziness

  • Case #11: Rhinitis

  • Case #12: Obesity 

  • Case #13:  Orthostatic Hypotension

  • Case #14:  Prescription Drug Effects - Beta Blocker

  • Case #15 : Effect of Pregnancy 

Case #1: Tachycardia (Fast Heart Rate)

Clinical observation

This patient , having common cold, showed a heart rate of 120/min.  HRV (14 ms) was also too low (normal 49 ms for a female at 26 years-old).  Common causes for fast heart rate include fever, cold/flu, alcohol, anxiety/depression, lack of sleep, obesity, pregnancy, hyperthyroidism, coffee/tea, fatigue, pain, breathing difficulty, etc.

Take-home message 

  • Identify the root cause of fast HR

  • Monitor  HR by ANSWatch-Mini until it falls within the normal range during the treatment course

  • Talk to your doctor if the treatment does not work 

Case #2: Bradycardia (Slow Heart Rate)

Clinical observation

This 18-years-old, thin male patient  showed a heart rate of 43/min.  A slow heart rate could be a result of athletic training and is healthy.   In most other situations, slow HR  leads to poor circulation in the form of hypoxia.  Our body’s circulation system is responsible for transporting blood, oxygen, nutrients and wastes throughout the body. Our heart rate is controlled in combination by three factors: (1) the natural rhythm, generated by special heart muscles at the sinus node (natural pacemaker) , at about 120/min (2) the sympathetic tone (LF) which increases HR (3) the parasympathetic tone (HF) which decreases HR .   When a slow HR is observed, one must suspect the following: (1) an abnormally slow natural rhythm (generic defect; some athletes have such conditions as well)(2) a high parasympathetic tone (HF) than normal (3) a weak heart that can not pump at normal HR.  Other health conditions that may cause slow HR include electrical pathways obstruction, metabolic problems such as hypothyroidism, certain heart medications that can cause bradycardia as a side effect.  

Take-home message 

  • Identify the root cause of slow HR

  • In ANSWatch-Mini tests,  attention should be paid to values of HR, blood pressures (watch out hypotension), HF, LF/HF, and any irregular heartbeats (IRRHB).  

Case #3a: Arrhythmia - Atrial Fibrillation (AF)

Clinical observation

This 72-years-old, thin male patient  showed a heart rate of 240/min during an AF episode (first figure above).   Other cardiac arrhythmia modes were observed in the patient besides AF, such as pulse-alternans (strong-weak alternating heartbeats; the second figure), and skipped heartbeats (third figure).  Often AF episodes have no symptoms.  

Occasionally there may be heart palpitationsfaintinglightheadednessshortness of breath, or chest pain.   The disease is associated with an increased risk of heart failuredementia, and stroke. 

Take-home message 

  • Consult with your physicians ASAP if you see AF in your test results

  • Pay attention to other arrhythmia modes as marked by AI of ANSWatch-Mini (if any)

  • Monitor the type and associated frequency of all arrhythmia

  • Share your test results recorded in your smartphone or tablets with your doctor

Case #3b: Ventriculaaar premature Contraction (VPC)

Clinical observation

This 61-years-old, female patient  exhibited 50 irregular heartbeats (IRRHB) during the 5-min test by ANSWatch.  All 50 IRRHB are the same type of arrhythmia called Ventricular Premature Contraction (VPC; or PVC, same disease).   On the charts above (first and second), a VPC event is characterized by an early heartbeat followed by a delayed heartbeat.   Furthermore, the early contraction is always a weak one (smaller peak) due to incomplete blood filling.  On the other hand, the delayed contraction is always stronger (filling spill-over).  This special pulse pattern of <early-small-delay-large> is readily recognized.   VPC is the most common type of cardiac arrhythmia, existing in 6% or more of middle-aged adults (45-65 years).  While generally not harmful, VPC often turns into other modes of IRRHB (such as skipped heartbeat, pulse alternans, or life-threatening AF) if not treated.

Take-home message 

  • Consult with your physicians ASAP if you see more than 20 IRRHB  in your ANSWatch test results

  • Pay attention to arrhythmia modes as marked by AI of ANSWatch-Mini (if any)

  • Monitor the type and associated frequency of all arrhythmia.  An increasing trend of any type is a warning sign.

  • Share your test results recorded in your smartphone or tablets with your doctor

Case #4: Pulse Alternans 

Clinical observation

The above two patients (66-years-old, female patient; first figure;   40-years-old, male patient; second figure) exhibited a particular pulse pattern called Pulse Alternans.  Pulsus alternans is a physical finding with arterial pulse waveform showing alternating strong and weak beats.  It is almost always indicative of left ventricular systolic impairment, and carries a poor prognosis (when observed with high frequency at resting conditions). 

Take-home message 

  • Consult with your physicians immediately if you see pulse alternans in your ANSWatch test results

  • Pay attention to other arrhythmia modes as marked by AI of ANSWatch-Mini (if any)

  • Share your test results recorded in your smartphone or tablets with your doctor

Case #5: Dialysis 

Clinical observation

The above 65-years-old female patient has been undergoing dialysis for more than two years.  What does dialysis do? When your kidneys fail, dialysis keeps your body in balance by removing waste, salt and extra water to prevent them from building up in the body.  The procedure also keeps a safe level of certain chemicals in your blood, such as potassium, sodium and bicarbonate, helping to control blood pressure. 

A common undesirable effect of dialysis, often ignored, is a gradual loss of autonomic control.  As seen above, the ANS total activity index HRV was too low (14 ms; normal 20 ms for her age and sex), sympathetic nerve index LF too low (10 ms**2; normal 100 ms**2), parasympathetic nerve index  HF too low (10 ms**2; normal 100 ms**2).

Take-home message 

  • Monitor your ANS parameters (HRV, LF, LF%, HF, HF%, LF/HF) at least once a week

  • Talk to your doctors if any of these parameters is in a decreasing/increasing trend or out of normal range

Case #6: Cancer (Esophageal)  

Clinical observation

The above 73-years-old male patient had esophageal cancer and underwent chemotherapy.  Common to most cancer-surviving patients,  the side effects of chemotherapy can stay with the body for a long period of time.  Alkylating agents used in chemotherapy treatments are highly toxic to nerve endings and often cause  autonomic dysfunction.  As seen above, the ANS total activity index HRV was too low (12 ms; normal 18 ms for his age and sex), sympathetic nerve index LF too low (15 ms**2; normal 80 ms**2), parasympathetic nerve index  HF too low (7 ms**2; normal 80 ms**2). The patient had a high HR (91/min) and 31 events of IRRHB (mostly skipped heartbeats, see the chart)

Take-home message 

  • For cancer patients (either completed or under active treatment), monitor your ANS parameters (HRV, LF, LF%, HF, HF%, LF/HF) at least once a week

  • Talk to your doctors if any of these parameters is in a decreasing/increasing trend or out of normal range

Case #7: Depression / Anxiety  

Clinical observation

The 60-years-old male patient has been seeing his psychiatrist for depression, anxiety, and sleep disorder.  He has taken sleeping pills for years.  For this group of patients, the feelings of relaxation, easiness, happiness, and satisfaction are gradually lost and replaced by stress, hopelessness, and anger.   The autonomic nervous system is no longer in  Yin-Yang balance (Yin for the para-sympathetic branch, while Yang for the sympathetic branch).  Vegal (or parasympathetic) withdrawal syndrome takes place eventually.  As seen above, the ANS total activity index HRV was low (19 ms; normal 25 ms for his age and sex), sympathetic nerve index LF too low (81 ms**2; normal 156 ms**2), parasympathetic nerve index  HF way too low (41 ms**2; normal 156 ms**2). The patient had 2 events of IRRHB (all VPCs, see the second chart above)

Take-home message 

  • For depression, anxiety, or sleep disorder patients, monitor your ANS parameters (HRV, LF, LF%, HF, HF%, LF/HF) at least once a week

  • Learn to practice deep breathing

  • Learn to conduct relaxation biofeedback with ANSWatch-Mini (More...)

  • Talk to your psychiatrist if any of prescribed drugs causes a decrease in HRV or HF 

Case #8: Diabetes  

Clinical observation

The 60-years-old male patient above has been taking diabetes medicine for several years.  From the above two tests, his body weight was in good shape (BMI 25.8).  His blood pressures were normal (SYS 129 mmHg; DIA 75 mmHg).  His HR was always on the high side ( 94, 88 beat/min).  His extremely low ANS activity index HRV (8 ms; normal 25 ms; biological age 95 years-old) is due to both low sympathetic nerve index (LF: 9-12 ms**2; normal 156 ms**2) and low parasympathetic nerve index (HF: 14-18  ms**2; normal 156 ms**2).  Irregular heartbeats (IRRHB) were not detected.   

 Decades of clinical experience in diabetes has  taught us to watch not only the glucose level, but also cardiovascular parameters.   Neuropathy in extremity is also a warning sign for more severe diabetes-induced diseases.  One area that is clinically important but often overlooked is ANS.  In general, at the beginning of diabetes, HRV and HF start to decrease (earlier than glucose reading increase).  As the disease progresses, LF also decreases, which brings down HRV (total activity index of ANS) further.  When HRV is lowered to a single digit (less than 10 ms), neuropathy of ANS is suspected.  Diabetic patients tend to take several classes of prescription drugs to cope with blood glucose, cardiovascular, hormone, and mental diseases.  Many of these drugs can interfere with ANS branches.  Beta blockers are well known to interrupt sympathetic signals to the brain and result in a lower LF.  Vasodilators (another class of BP lower agents) tend to lower HF.  Insulin injection can alter HR and HRV (dose dependent).   Monitoring of cardiovascular and ANS parameters (as provided by home-testing ANWatch-Mini) is highly recommended.

Take-home message 

  • Monitor your cardiovascular parameters (blood pressures, heart rate, IRRHB) and ANS parameters (HRV, LF, LF%, HF, HF%, LF/HF) at least once a week

  • Monitor on daily basis if there is a recent change in prescription

  • Exercise is your best friend for health.  Watch all the physiological parameters cited above to improve together

  • Talk to your family doctor and cardiologist  if any of prescribed drugs causes a decrease in HRV, LF, or HF 

Case #9a: Deep Breathing

(Pea-to-peak interval vs. Time plot; Normal natural breathing)

(Pea-to-peak interval vs. Time plot; Inhale 3-sec, exhale 3-sec)

(Pea-to-peak interval vs. Time plot; Inhale 4-sec, exhale 4-sec)

(Pea-to-peak interval vs. Time plot; Inhale 5-sec, exhale 5-sec)

Clinical observation

The above 23-years-old, healthy male subject conducted a series of <Real-time test> (a test mode available on ANWatch-Full-Size and ANSWatch-Mini) to study the physiological effects induced by deep breathing.  There were four breathing conditions: (1) normal or natural breathing (about 14 cycles per min for an adult) (2) 3-sec inhale and 3-sec exhale (10 cycles per min; conducted using a stop watch on smart phone) (3) 4-sec inhale and 4-sec exhale (7.8 cycles per min) (4) 5-sec inhale and 5-sec exhale (6 cycles per min). 

From the first figure above,  as the breathing rate got slower and into the deep breathing area (5-sec, 5-sec), the following effects showed up: (1) HR decreased (2) HRV increased (3) LF/HF increased (4) LF increased (5) HF decreased.

From the 2nd through 4th figures above for the Peak-to-peak interval vs. Time plots,  the breathing patterns became more pronounced with noticeable inhale-exhale tops as the respiration cycle slowed.

It is important to note that in the 1996 HRV Standard (Circulation. 1996;93:1043-1065.© 1996 American Heart Association, Inc.), the frequency range for the sympathetic branch (LF; 0.04 to 0.15 Hz) and that of  the parasympathetic branch (LF: 0.15 to 0.40 Hz) are defined based upon a normal respiration cycle of a human subject under resting conditions (9-24 cycles per min).  Deep breathing involves a very slow cycle and thus is outside of the norm.  Our studies demonstrate that a significant portion of parasympathetic nerve signals (defined as HF in the 1996 Standard)  are shifted to the region of LF.  As a result, HF is under-reported, LF is over-reported, and LF/HF is over-reported.  

Therefore, when conducting deep breathing and examining test results, pay most attention to the HRV increase and HR decrease, two strong indications for body relaxation.  See the next clinical case for more discussion on deep breathing principle.

Case #9b: Relaxation Biofeedback

Clinical observation

The above 28-years-old, healthy female subject conducted a two-step <Real-time test>, natural breathing followed by free deep breathing (inhale-hold-exhale).  The test was conducted with the subject wearing ANSWatch-full-size and watching the computer screen for instant physiological response and mental feedback. 

From the first figure above,  ANSWatch reports the following parameters on a real-time basis: (1) pulse wave pattern (2) peak-to-peak interval (3) HRV (every 10-sec) (4) HR (every 10-sec). 

From the second figure which displays the entire 300-sec test, first of all, it is noted that while peak-to-peak intervals had minute variations during natural or chest breathing (step 1), a clear pattern of inhale-hold-exhale can be seen during deep or diaphragmatic breathing (step 2).  Deep breathing induced relaxation  caused the following effects: (1) HR decreased (2) HRV increased.  Values of LF, LF%, HF, HF%, and LF/HF were not correct as frequency shift occurred (as discussed in Case #9a). 

During deep breathing,  the respiration center in the brain sends strong vagus nerve signals (parasympathetic) to the heart, causing the heart rate, ventricle contraction, and the cardiac output to slow down.   This relaxation effect is most pronounced if the subject also keeps the thought to be minimal.  Any emotional  arousal (excitement, sorrow, anxiety, nervousness, etc.) may  bring about countering ANS actions.  

Some psychiatrists and psychologists have been promoting this technique.  They ask their patients to report to the clinic 30 minutes earlier before appointment.  Patients then practice deep breathing/relaxation biofeedback for 20 minutes (the time limit set by ANSWatch) in front of a desk computer while wearing ANSWatch.  When patients go home, they are instructed to practice the same technique with both eyes closed for 30 minutes, each time after taking the prescription.   Reports on follow-ups have been very positive.  One particular patient with major depression, panic attack, and sleep disorder has since improved so much that he now needs 3 pills a day, instead of 6. 

Take-home message for Case #9a and #9b

  • Deep breathing is an easy-to-follow technique that benefits patients greatly with mental disorder

  • Deep breathing is also useful for people coping with stress and sleep difficulty

  • Practice deep breathing before event to reduce performer's anxiety

  • Expect positive changes in your cardiovascular parameters (blood pressures, heart rate, IRRHB) and ANS parameters (HRV, LF, LF%, HF, HF%, LF/HF) 

  • Monitor on daily basis if there is a recent change in prescription  

Case #10: Fainting / Diziness  

Clinical observation

The 22-years-old female patient above has been complaining about dizziness and fainting.  Upon ANS examination by ANSWatch, a consistently low LF/HF (0.3 to 0.4; sympatho-parasympathetic balance index) is to be blamed.   The annoying  symptom often is genetic.  Certain prescription drugs, such as beta blockers, can also lower LF/HF (by blocking sympathetic signals).   When our body moves or change posture, ANS keeps our blood flow in a balanced state.  For instance, when you lie down on a bed for a while and suddenly stand up, the blood in the brain tends to flow down towards the lower body.  ANS detects this effect and counter it by constricting arteries (through activating sympathetic nerves or de-activating parasympathetic nerves).   Without ANS's compensation, the brain would become ischemia temporarily.  Dizziness or fainting can become a bigger issue if ischemia or hypoxia  lasts too long, resulting in falling or injury.  

Take-home message 

  • Avoid taking beta or alpha blockers (which are often prescribed for hypertension of fast HR)

  • Monitor your cardiovascular parameters (blood pressures, heart rate, IRRHB) and ANS parameters (HRV, LF, LF%, HF, HF%, LF/HF) at least once a week

  • Endurance exercise is best for people with a low LF/HF.  This type of exercise helps to activate and train the sympathetic branch

  • Also called aerobic exercise, endurance exercise includes activities that increase your breathing and heart rate such as walking, jogging, swimming, and biking.

  • Endurance activity keeps your heart, lungs and circulatory system healthy and improves your overall fitness.

  • Watch your LF and LF/HF to go up as you develop and execute your exercise routine

  • Talk to your family doctor and cardiologist  if any of prescribed drugs causes a decrease in HRV, LF, or  LF/HF

Case #11:  Rhinitis  

Clinical observation

The 53-years-old male patient above has been diagnosed with severe allergy and rhinitis.   Upon ANS examination by ANSWatch, low LF (sympathetic nerve index; 25 ms**2; normal 175 ms**2 for his age and sex) and  low LF/HF (sympatho-parasympathetic balance index; 0.3; normal 1.0) were discovered.     

Narrowing or partial blockage of the nasal airway is often observed for patients with general allergy and with rhinitis in particular.   With insufficient air or oxygen supply, ANS adjusts the body to operate at a low-activity state by toning down the sympathetic branch (LF).   While ANS's action is totally adequate, the patient may feel low-energy, tired, or loss of interest.  With compromised circulation, the immune system may go down as well.  Caution should be taken for these patients taking antihistamines.  Antihistamines tend to exhibit anticholinergic effects and may interfere with the parasympathetic branch (HF)

Take-home message 

  • Monitor your cardiovascular parameters (blood pressures, heart rate, IRRHB) and ANS parameters (HRV, LF, LF%, HF, HF%, LF/HF) at least once a week

  • Endurance exercise is best for people with allergy or rhinitis.  This type of exercise opens the nasal airway and strengthens your heart, lungs and circulatory system 

  • Watch your LF and LF/HF to go up as you develop and execute your exercise routine

  • Talk to your family doctor, internist, or cardiologist  if any of prescribed drugs causes a decrease in HRV, LF, HF, or  LF/HF

Case #12:  Obesity  

Clinical observation

The 44-years-old male patient above has been obese (BMI 34.5) for several years.  He considers himself healthy.   Upon ANS examination by ANSWatch, several warning signs  were found: (1) high HR (103 beat/min) (2)  way low (single digit) HRV (8 ms; normal 30 ms) (3) very low LF (20 ms**2; normal 185 ms**2)  and extremely low HF (less than 1 ms**2; normal 185 ms**2) (4) very high LF/HF  (24.0; normal 1.0).  See the first figure.

Further evidence of ANS modulation loss is shown on the third figure.  The peak-to-peak intervals vs. time plot is essentially a flat line.  In contrast, for a healthy subject wth active ANS, on the forth figure, the peak-to-peak intervals vary with time.

The patients's blood pressures (SYS 115 mmHg; DIA 69 mmHg) were normal, but that is a result of hypertension drugs.   Most hypertension medicines can interfere with ANS.  Beta or alpha blockers tend to reduce the sympathetic nerve signals (LF), while vasodilators (ACE inhibitors or calcium channel blockers) attenuate the parasympathetic nerve signals (HF).  The patient's low HRV, LF, and HF could be in part due to medicinal effects. 

In terms of overweight and obesity, commonly accepted BMI ranges are underweight: under 18.5 kg/m2; normal weight: 18.5 to 25; overweight: 25 to 30; obese: over 30.  As the body weight increases from a healthy level, additional energy is needed to support the body activity.   ANS adapts by reducing the parasympathetic tone (HF), which increases heart rate and cardiac output. This action also brings down HRV and HF, and raises LF/HF above 1.0.    Eventually, LF also goes down in order to keep LF/HF within a reasonable range.  Most obese patients are expected to exhibit some degree of dysautonomia or ANS imbalance.  

Take-home message 

  • Understand the weight issues from the ANS point of view

  • Loss of HF for a long term may induce sleep and mental problems.  Anxiety and depression are seen commonly among obese patients.

  • Overweight or obesity can affect your cardiovascular system. Monitor your cardiovascular parameters (blood pressures, heart rate, IRRHB) and ANS parameters (HRV, LF, LF%, HF, HF%, LF/HF) at least once a week

  • Watch your HRV and HF to go up, LF/HF to go down, and sleep problems to go away as you develop and execute your diet/weight loss plan

Case #13:  Orthostatic Hypotension  

Clinical observation

The 75-years-old male patient above has been diagnosed with orthostatic hypotension and Parkinson.  Orthostatic hypotension, also known as postural hypotension, occurs when a person's blood pressure falls when suddenly standing up from a lying or sitting position.  From the first figure, the test with a lying posture showed a blood pressure of 158/94 mmHg.  Immediate re-test with a sitting posture showed 108/70 mmHg.  

When a person abruptly stands up from lying or sitting, the blood in the brain has a tendency to flow downward (the gravity effect).  For healthy people, ANS, without brain thinking, immediately constricts blood vessels (by either withdrawing the parasympathetic tone, or activating the sympathetic tone) to prevent the blood from dropping.   People with postural hypotension often feel dizzy or even faint during an sudden postural change.  When the ANS feedback control is inadequate, all elements in the control loop must be suspected, including baroreceptors (the biosensors in the body that sense the blood pressure at various parts of body), neurotransmitters, the communication between the central nervous system (CNS) and ANS, and the health of major arteries.  Doctors may prescribe a medication to treat the orthostatic hypotension, such as fludrocortisone (Florinef®), midodrine(ProAmatine®), or erythropoietin (Epogen®, Procrit®).  These drugs work by increasing blood volume or by constricting (narrowing) blood vessels.

Take-home message 

  • Understand the linkage between orthostatic hypotension and ANS 

  • Avoid sudden postural change, especially when the body is tired, sleepy, sitting in a confined space for a long time (such as driving, movie watching, etc.), after a long flight, or traveling abroad

  • Many orthostatic hypotension cases are genetic.  Training of your ANS control is helpful.  Include both aerobic exercise and deep breathing/meditation (i.e. dynamic and static double yoga)  in your training program

  • Monitor your cardiovascular parameters (blood pressures, heart rate, IRRHB) and ANS parameters (HRV, LF, LF%, HF, HF%, LF/HF) on a daily basis

  • Talk to your doctor about your ANS test results in relation to prescription

Case #14:  Prescription Drug Effects - Beta blocker  

Clinical observation

The 56-years-old male patient above has been taking hypertension drug (beta blocker) for years.  Beta blockers, also known as beta-adrenergic blocking agents, are medications that reduce your blood pressure. Beta blockers work by blocking the signal of the hormone epinephrine, also known as adrenaline, the neurotransmitter used by the sympathetic branch (LF) in ANS. When you take beta blockers, your heart beats more slowly and with less force, thereby reducing blood pressure.  From the above figures, the ANSWatch test showed a blood pressure of 105/71 mmHg.  These values are a bit lower than normal, considering the patient's age of 56.  Ideal BP after medication adjustment should be about 130/80 mmHg.  His HR at 120 beat/min is still way high. The patient told us that his phdysician did not conduct an ANS test on him.   His high BMI (26, overweight) may have contributed to high BP (before medication) and HR.  Beta blockers are known to reduce LF and LF%.  From the  above figures, his LF was 2 ms**2 while a normal value of  160 ms**2 is expected for his age and sex .   LF% is 10% (normal 50%).  When our body adjusts physiology in response to a postural change,  it relies on ANS.    For this patient, the sympathetic modulation is almost lost.  His parasympathetic nerve index HF is also low (18 ms**2, normal 160 ms**2).  The test results are  consistent with his complaint of dizziness.  

Take-home message 

  • Understand the linkage between beta blockers and  ANS 

  • When possible, test your ANS before taking hypertension medicine

  • According to American medical Association AMA, patients with a systolic pressure higher than 150 mmHg needs medication. 

  • Weight reduction is helpful for fighting hypertension

  • Ideal blood pressure range is at 130-140 mmHg for people in the age of 50 or older.  No further benefit for controlling BP lower than 130 mmHg.

  • When ANS test shows a very low LF, LF%, and LF/HF, talk to your doctor to switch prescription

  • When you feel fainting or dizzy while taking hypertension medicine, talk to your doctor about drug class change (from beta blockers to vaso-dilators, such as calcium channel blockers)

  • Monitor your cardiovascular parameters (blood pressures, heart rate, IRRHB) and ANS parameters (HRV, LF, LF%, HF, HF%, LF/HF) on a weekly basis

Case #15:  Effect of Pregnency 

Clinical observation

The 34-years-old female patient above first came to the clinic and underwent ANSWatch test with 5-month pregnancy.  Since then, followup tests were conducted at 7-month and 8-month pregnancy, as well as 3-month and 4-month after giving birth.  The test results shown on first and second figures above clearly show the following pregnancy effects on physiology: (1) HR was faster during pregnancy than normal (88-103 with pregnancy vs. 81-86 after giving birth); HR  became very fast at late pregnancy (103 beat/min at 8-month) (2) HRV was lower during pregnancy than normal (24-36 ms with pregnancy vs. 44-47 ms after giving birth) (3) LF/HF was higher during pregnancy than normal (1.0 - 2.7 with pregnancy vs. 0.6-0.9 after giving birth) (4) the reduced HRV during pregnancy was primarily caused by reduction in HF (parasympathetic branch) (81-361 with pregnancy vs. 531-686 after giving birth).  

Take-home message 

  • Pregnancy is a significant challenge to physiology and homeostasis

  • ANS helps the body to output additional bio-energy by toning down the parasympathetic nerve HF, which results in a higher HR, a higher LF/HF, and  a  lower HRV

  • The new body state of sympathetic dominance often comes with insomnia, frequent urination, dry mouth, abdominal distension, and edema

  • Prescriptions given by your gynecologist may be interfering with ANS

  • Monitor your cardiovascular parameters (blood pressures, heart rate, IRRHB) and ANS parameters (HRV, LF, LF%, HF, HF%, LF/HF) on a weekly basis

  • When ANS test shows a very low HF, HF%, and a very high LF/HF, talk to your doctor to switch prescription

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