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Cardiovascular

Heart Rate

What is it? Heart rate refers to the frequency of heart contractions in one minute, or the number of beats of the heart per minute (bpm). The heart pumps blood containing oxygen and nutrients to the body and removes waste products by transporting them to the liver, kidneys, or intestines.

How do I interpret this value? Heart rate varies from person to person and can change over time. A slow or fast heart rate can cause symptoms such as dizziness or tiredness. Abnormal values may be indicative of underlying health problems such as arrhythmia or heart disease. Maintaining a healthy lifestyle and seeking medical attention when necessary can help improve the heart rate.

Unit of Measurement: bpm

General Range

RangeCondition
> 100 (Tachycardia) or < 60 (Bradycardia)Cautious
81-100Poor
60-80Excellent

Male Range

AgeValueCondition
18-25>82Poor
74-81Below Average
70-73Average
66-69Above Average
62-65Good
56-61Excellent
26-35>82Poor
75-81Below Average
71-74Average
66-70Above Average
62-65Good
55-61Excellent
36-45>83Poor
76-82Below Average
71-75Average
67-70Above Average
63-66Good
57-62Excellent
46-55>84Poor
77-83Below Average
72-76Average
68-71Above Average
64-67Good
58-63Excellent
56-65>82Poor
76-81Below Average
72-75Average
68-71Above Average
62-67Good
57-61Excellent
>65>80Poor
74-79Below Average
70-73Average
66-69Above Average
62-65Good
56-61Excellent

Female Range

AgeValueCondition
18-25>85Poor
79-84Below Average
74-78Average
70-73Above Average
66-69Good
61-65Excellent
26-35>83Poor
77-82Below Average
73-76Average
69-72Above Average
65-68Good
60-64Excellent
36-45>85Poor
79-84Below Average
74-78Average
70-73Above Average
65-69Good
60-64Excellent
46-55>84Poor
78-83Below Average
74-77Average
70-73Above Average
66-69Good
61-65Excellent
56-65>84Poor
78-83Below Average
74-77Average
69-73Above Average
65-68Good
60-64Excellent
>65>85Poor
77-84Below Average
73-76Average
69-72Above Average
65-68Good
60-64Excellent

The normal resting heart rates ranges from 60-80 bpm.

References:

  1. WebMD
  2. Mayoclinic
  3. MedicineNet

Heart Rate Variability

What is it? Heart Rate Variability (HRV) is a measure of the variation in time between successive heartbeats. It is considered an important indicator of the autonomic nervous system function, particularly the balance between the sympathetic (stress response) and parasympathetic (relaxation response) branches.

HRV is often analyzed using different time-domain and frequency-domain measures. Vitals provides three HRV metrics: SDNN, Mean IBI and RMSSD.

References:

  1. WebMD
  2. Cleveland Clinic

HRV-Mean IBI (Interbeat Interval)

HRV-IBI is the most basic measure of HRV, representing the time interval between successive heartbeats. The IBI is still measured in milliseconds (ms) and represents the variations in time between consecutive heartbeats.

Unit of Measurement: ms

ValueCondition
<600At risk
600-605Poor
705-857Good
857-1200Excellent

HRV-SDNN (Standard Deviation of NN Intervals)

HRV-SDNN is a measure of the overall variability in heart rate. It is calculated as the standard deviation of all normal-to-normal (NN) intervals, which are the time intervals between successive normal heartbeats. A higher SDNN value indicates greater variability in heart rate, which is generally associated with better cardiovascular health and autonomic function.

Unit of Measurement: ms

ValueCondition
<10.8At risk
10.8-16.4Poor
16.4-35.0Cautious
35.0-51.5Good
>51.5Excellent

Heart rate variability SDNN above 35 ms are healthy.

HRV-RMSSD (Root Mean Square of Successive Differences)

HRV-RMSSD is another time-domain measure of HRV that specifically reflects the short-term variability in heart rate and is considered a good indicator of parasympathetic activity. It is calculated as the square root of the mean of the squared differences between successive NN intervals. Higher RMSSD values indicate greater short-term variability and are generally associated with better cardiovascular health and stress resilience.

Unit of Measurement: ms

Blood Pressure

What is it? Blood pressure is the force exerted by blood against the walls of the arteries as the heart pumps it through the body. It is an important indicator of cardiovascular health.

How do I interpret this value? A blood pressure reading outside the normal range indicates a higher risk of health problems. High blood pressure (hypertension) can lead to serious health conditions such as heart disease and stroke, while low blood pressure (hypotension) can cause dizziness and fainting. Lifestyle factors such as diet, exercise, and stress management can help improve blood pressure.

How is it measured? Blood pressure is measured by a machine learning model that analyses features of the rPPG signal, such as Pulse Transit Time, which is the time it takes for the blood pressure pulse wave to travel between two arterial sites.

References:

  1. Europepmc
  2. Cleveland Clinic

Systolic Blood Pressure

Systolic blood pressure is the pressure in the brachial arteries when the heart is actively contracting and pumping blood. A low SBP value can lead to symptoms such as dizziness and fainting and may be a sign of heart problems or dehydration. A high SBP value is often associated with hypertension, which increases the risk of heart attack, stroke, and kidney disease.

Unit of Measurement: mmHg

ValueCondition
<90Cautious
90-120Excellent
120-130Good
130-140Cautious
>140At risk

The ideal systolic blood pressure is between 90-120mmHg.

Diastolic Blood Pressure

Diastolic blood pressure refers to the pressure in the brachial arteries when the heart is at rest between beats. A low DBP value can indicate insufficient blood flow and oxygen supply to the heart, brain, and other organs, while a high DBP value may suggest increased resistance in the blood vessels, leading to hypertension or other cardiovascular problems.

Unit of Measurement: mmHg

ValueCondition
<60Cautious
60-70Excellent
70-80Good
80-90Cautious
>90At risk

The ideal diastolic blood pressure is between 60-80 mmHg.

Cardiac Workload

What is it? Cardiac workload is a measure of how hard the heart is working to pump blood through the body. It is an important indicator of cardiovascular health.

How do I interpret this value? Cardiac workload can vary depending on individual factors such as age, fitness level, and overall health. Generally, a high cardiac workload at rest may indicate poor cardiovascular health. Athletes or people who exercise regularly tend to have lower values, while those who don't exercise may have higher values. Maintaining a healthy lifestyle through regular exercise, healthy diet, and stress management can help improve cardiac workload.

How is it measured? Cardiac workload is measured by calculating the product of heart rate and systolic blood pressure, which gives an estimate of the amount of work the heart is doing per minute.

References:

  1. Cleveland Clinic
  2. PubMed
  3. ScienceDirect
  4. Hypertension

Pulse Respiratory Quotient (PRQ)

What is it? Pulse Respiratory Quotient (PRQ) is a measure of how well the cardiovascular and respiratory systems are working together and can indicate overall cardiovascular and respiratory health. PRQ can vary depending on the type of exercise being performed. For example, during aerobic exercise, PRQ tends to increase as the body produces more carbon dioxide, whereas during anaerobic exercise, PRQ tends to decrease as the body produces more lactic acid.

How do I interpret this value? PRQ values can be affected by factors such as exercise, stress, and respiratory issues. A low or high PRQ may indicate underlying health problems. For example, a high PRQ may indicate respiratory distress or hyperventilation, while a low PRQ may indicate poor cardiovascular health.

How is it measured? PRQ is measured by dividing the pulse rate by the respiratory rate.

References:

  1. PubMed
  2. Frontiers

Cardiovascular Disease

Cardiovascular disease (CVD) refers to a group of conditions that affect the heart and blood vessels, including the arteries, veins, and capillaries. CVD can lead to serious health problems such as heart attacks, strokes, heart failure, and peripheral artery disease.

Unit of Measurement: %

Risk Category10-Year Risk of CVD Events
Low Risk<5%
Borderline Risk5% to <7.5%
Intermediate Risk7.5% to <20%
High Risk≥20%

References:

  1. https://www.acc.org/

Framingham General Cardiovascular Risk Score (FGCRS)

FGCRS is a multivariable risk function that predicts the risk of developing all CVD and its constituents, including coronary heart disease (heart attack), stroke etc.

Inputs to the function:

  • Age
  • Total-C
  • HDL-C
  • Systolic Blood Pressure
  • Blood Pressure Treatment times
  • Smoking
  • Diabetes
  • Incident CVD events

References:

  1. https://www.ahajournals.org/

Framingham Coronary Heart Disease Risk Score (FCHDRS)

FCHDRS is a simple coronary disease prediction algorithm using categorical variables, which allows physicians to predict multivariate CHD risk in patients without overt CHD. The accuracy of this categorical approach was found to be comparable to CHD prediction when the continuous variables themselves were used.

Inputs to the function:

  • Age
  • Total Cholestrol
  • HDL Cholestrol
  • Systolic Blood Pressure
  • Treated for blood pressure (Yes/No)
  • Smoker (Yes/No)

Reference:

  1. https://www.mdcalc.com/

Framingham Stroke Risk Score (FSRS)

The revised (new) version of the Framingham Stroke Risk Profile (FSRP) which predicts the risk of all-stroke and ischemic stroke in 10 years.

Inputs to the function:

  • Age
  • Systolic Blood Pressure
  • Glucose level
  • Smoker (Yes/No)
  • Prevalent Cardiovascular Disease (Yes/No)
  • Atrial Fibrillation (Yes/No)
  • Left Ventricular Hypertrophy (Yes/No)
  • Diabetes Mellitus (Yes/No)
  • Hypertension Medications (Yes/No)

References:

  1. https://onlinelibrary.wiley.com/

Framingham Heart Failure

Framingham Heart Failure is the probability of developing heart failure within the next 4 years based on the presence of the relevant risk factors specified above. Using the risk factors that make up the multivariate risk formulation derived from ordinary office procedures, the probability of developing heart failure can be estimated and compared with the average risk for persons of the same age and sex.

Using this risk profile, 60% of events in men and 73% in women occurred in subjects in the top quintile of multivariate risk. The risk profile may also identify candidates who are at high risk for heart failure because of multiple, marginal risk factor abnormalities that might otherwise be overlooked.

Inputs to the function:

  • Age
  • Left Ventricular Hypertrophy (Yes/No)
  • Cardiomegaly (Yes/No)
  • Heart Rate
  • Systolic Blood Pressure
  • Vital Capacity
  • Diabetes Mellitus (Yes/No)
  • Evidence of Myocardial Infarction
  • Valvular Disease or Hypertension

References:

  1. https://jamanetwork.com/