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Heart Rate
Variability (HRV),
Heartbeats, and
Autonomic Nervous
System (ANS)
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ANSWatch customers
(professionals and
individuals) for
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in-depth discussions at  
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Do you have     
- are you monitoring   
- are you taking
prescription drugs?
- are you aware of drug
side effects on ANS?
- self-improvement tips
Read more......
Feeling dizzy      
or even fainted?
- are you low in blood
pressure or heart rate?
- are you taking
prescription drugs?
- You may experience
Baroreflex failure
Read more......
Irregular heartbeats?
- often noticing abnormal
heartbeats (missing,
uneven, or super-fast)?
- Yo might have cardiac
- Most sudden death
events are preceded by
irregular heartbeats
Read more......
Mitral Valve Prolapse?
- Mitral valve is the
bicuspid valve between left
atrium and ventricle
- If mitral valve is not
closed properly (called
mitral valve prolapse
MVP), the blood may
backflow during pumping
- there is a strong
connection between panic
attackes and MVP
- How to detect it?
Read more......
Am I having   
- autonomic nervous
system works to fine tune
body conditions depending
on physiological needs
- ANS consists of two
branches: sympathetic and
- do you have balanced
- what are the symptoms of
Read more......
Hypertension and its Impact on Health
Glimpse of Facts on Hypertension

  • Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic
    arterial blood pressure is elevated. It is the opposite of hypotension.
  • Hypertension is classified as either primary (essential) hypertension or secondary hypertension;
    About 90–95% of cases are categorized as "primary hypertension," which means high blood
    pressure with no obvious medical cause. The remaining 5–10% of cases (Secondary
    hypertension) are caused by other conditions that affect the kidneys, arteries, heart or
    endocrine system.
  • Persistent hypertension is one of the risk factors for stroke, myocardial infarction, heart failure
    and arterial aneurysm, and is a leading cause of chronic kidney failure
  • Moderate elevation of arterial blood pressure leads to shortened life expectancy.
  • Dietary and lifestyle changes can improve blood pressure control and decrease the risk of
    associated health complications, although drug treatment may prove necessary in patients for
    whom lifestyle changes prove ineffective or insufficient
Do I have Hypertension?
  • Normal ranges of blood pressures are listed in Table 1
  • Hypertension has several sub-classifications including, hypertension stage I, hypertension stage
    II, and isolated systolic hypertension. Isolated systolic hypertension refers to elevated systolic
    pressure with normal diastolic pressure and is common in the elderly.
  • Individuals older than 50 years are classified as having hypertension if their blood pressure is
    consistently at least 140 mmHg systolic or 90 mmHg diastolic.
  • Patients with blood pressures higher than 130/80 mmHg with concomitant presence of diabetes
    mellitus or kidney disease require further treatment
Table 1: Classification of Hypertension
Causes of Essential Hypertension

  • Essential hypertension is the most prevalent hypertension type, affecting 90–95% of
    hypertensive patients.
smoking, stress, visceral obesity, potassium deficiency (hypokalemia), obesity, salt (sodium)
sensitivity, alcohol intake, and vitamin D deficiency that increase the risk of developing hypertension.
  • Risk also increases with aging, some inherited genetic mutations, and having a family history of
  • An elevated level of renin, a hormone secreted by the kidney, is another risk factor, as is
    sympathetic nervous system overactivity. Insulin resistance, which is a component of syndrome
    X (or the metabolic syndrome), is also thought to contribute to hypertension.
Causes of Secondary Hypertension

  • Secondary hypertension by definition results from an identifiable cause.
  • This type is important to recognize since it's treated differently to essential hypertension, by
    treating the underlying cause of the elevated blood pressure.
  • well-recognized secondary causes such as Cushing's syndrome, which is a condition where the
    adrenal glands overproduce the hormone cortisol.
  • Hypertension is also caused by other conditions that cause hormone changes, such as
    hyperthyroidism, hypothyroidism, and certain tumors of the adrenal medulla (e.g.,
  • Other common causes of secondary hypertension include kidney disease, obesity/metabolic
    disorder, pre-eclampsia during pregnancy, the congenital defect known as coarctation of the
    aorta, and certain prescription and illegal drugs.
Mechanisms of Essential Hypertension

Some mechanisms on the physiological levels have been  proposed
  • It is known is that cardiac output is raised early in the disease course, with total peripheral
    resistance (TPR) normal
  • It is also known that over time cardiac output drops to normal levels but TPR is increased.
  • Mechanism I: inability of the kidneys to excrete sodium, resulting in natriuretic factors such as
    Atrial Natriuretic Factor being secreted to promote salt excretion with the side effect of raising
    total peripheral resistance.
  • Mechanism II: aqn overactive Renin-angiotensin system leads to vasoconstriction and
    retention of sodium and water. The increase in blood volume plus vasoconstriction leads to
  • Mechanism III: an overactive sympathetic nervous system, leading to increased stress

  • The first line of treatment for hypertension are the same as the recommended preventative
    lifestyle changes, including dietary changes, physical exercise, and weight loss
  • Several classes of medications, collectively referred to as antihypertensive drugs, are currently
    available for treating hypertension.
  • Reduction of the blood pressure by 5 mmHg can decrease the risk of stroke by 34%, of
    ischaemic heart disease by 21%, and reduce the likelihood of dementia, heart failure, and
    mortality from cardiovascular disease.
  • The aim of treatment should be to reduce blood pressure to <140/90 mmHg for most
    individuals, and lower for individuals with diabetes or kidney disease (some medical
    professionals recommend keeping levels below 120/80 mmHg).
  • The first line antihypertensive supported by the best evidence is a low dose thiazide-based
  • Often multiple medications in combined are needed to achieve the goal blood pressure.
    Commonly used prescription drugs include: ACE inhibitors, alpha blockers, angiotensin II
    receptor antagonists , beta blockers , calcium channel blockers, diuretics (e.g.
    hydrochlorothiazide), direct renin inhibitors.
Hypertension, ANS and HRV

  • Sympathetic nervous system (SPN) over-activity is one of the identified causes in both
    essential and secondary hypertension
  • It has been documented that some hypertension medications can affect ANS and HRV
  • Beta blockers are used to treat hypertension by attenuating the activity of sympathetic nervous
    system (SPN)
  • Before beta blockers are prescribed, it is recommended that HRV tests are conducted to
    confirm overactivity of SPN (i.e. sympathetic-parasympethetic balance ratio LF/HF being at
    least 2.0 or higher; LF/HF of 1.0 being at balance)
  • In our clinical experience, many patients taking hypertension prescriptions exhibited LF/HF
    values way too low.  Some are as low as 0.1 indicating almost total loss of SPN modulation.
  • These patients often complained about being tired, exhausted, lightheaded, dizzy, short of
    breath, or ringing in ears.  Postural hypotension (not hypertension) is suspected in these
  • For experienced HRV professionals, we suggest that you not only look at LF/HF, but also LF
    and HF in absolute units during patient examination stage.  LF, representing the activity index
    of SPN, should be about 400 (unit: ms**2) for healthy young patients, 200  for people in 30-50,
    100 for 50-60, and 60-100 for older than 60 years-old.  If LF values are higher than these
    normal ranges, prescription drugs for suppression of SPN activity are appropriate
  • Some hypertension patients showed reduced LF and HF compared to normal values.  For such
    patients, even though LF/HF is greater than 1.0, beta blockers might not be the right choice.  
    These patients tend to have a lower HRV overall (the total ANS activity).
  • If you are a hypertension patient and you find your LF and LF/HF parameters too low, we
    suggest that you talk to your doctor to modify the prescription ASAP.