A study population with impaired fasting glucose levels, impaired glucose tolerance levels and diabetes (with or without complications) along with healthy patients will be chosen as participants. Their vital signs and their ECG (electrocardiograph) will be recorded during their only visit. Data analysis will be performed using the vital signs parameters. The RR intervals from the ECG will be analyzed by 5 different techniques to determine the best technique that stratifies the subjects the most accurately.

The Autonomic Nervous System (ANS) is a fundamental part of the nervous system in the body. And yet, there is no technique to test or measure the health and functioning of a person's autonomic nervous system.This type of study will determine the most accurate methodology to test the autonomic nervous system through heart rate variability (HRV) monitoring and gain vital information to distinguish patient groups in the diabetic population.

There is no gold standard for measuring autonomic dysfunction. Currently the method of power spectral analysis is finding very wide usage. It Is known that power spectral analysis does not discriminate the two subsystems of the ANS well. There are other beat to beat methodologies that have not yet gained traction. The reason for conducting this trial is to take a group of subjects in various stages of impaired fasting glucose, impaired glucose tolerance and diabetes (with and without complications) and determine which methodology stratifies these subjects most accurately.

Our study aims to introduce a new measurement method named the 'Beat to Beat' (BB) method for gauging autonomic dysfunction in patients. The investigators hope to observe that the average beat to beat method (BB) score could help discriminating diabetic patients into the following five distinct groups from the pilot study:

1. Normal blood glucose level: - (A blood sugar level less than 140 mg/dL)
2. Impaired fasting glucose (IFG): - (A fasting blood sugar level from 100 to 125 mg/dL)
3. Impaired glucose tolerance (IGT): - (two-hour glucose levels of 140 to 199 mg per dL
4. Diabetes without complications: - (e.g., no neuropathy, no retinopathy or nephropathy)
5. Diabetes with complications: - (at least one complication among neuropathy, retinopathy, or nephropathy)

By showing that this measurement bears no relationship to the other four vital signs parameters (heart rate, blood oxygenation, blood pressure, body temperature), it will prove the necessity of this measurement in addition to the four vital signs for distinguishing patient groups among the diabetic population.

Inclusion Criteria:

• Can provide informed consent.
• Age between 18 and 85 years old
• Body Mass Index: 25 ≤ BMI ≤ 40
• Hemoglobin A1c level: 7.5 ≤ HbA1c ≤ 9.5
• Individuals with pre-diabetes and diabetes Type II for at least 1 year (diagnosed by ADA criteria) and up to 20 years
• Advanced diabetic complications including neuropathy, nephropathy, retinopathy and other related complications
• Stable dose of medications for the previous 3 months
• Stable diet and lifestyle for the previous 3 months
• Stable medical status (Ex: no myocardial infarction, stroke, major surgery,

Exclusion Criteria:

• Unable to provide informed consent
• Chronic disease (e.g. HIV, Cushing syndrome, CKD, acromegaly, active hyperthyroidism etc.)
• Cancer and anticancer treatment in the last 5 years
• Psychiatric disorders (that in the eyes of the investigator should exclude the participant)
• Any disorder, which in the investigator's opinion might jeopardize subject's safety or compliance with the protocol
• Organ (kidney, pancreas, liver) transplant recipients
• Pregnancy or lactation
• Positive drug screen (opiates, methadone, cocaine, amphetamines, cannabinoids, barbiturates, benzodiazepines, tricyclic antidepressants and alcohol)
• Alcoholics or Smokers
• Positive screen on HBsAg, anti-HCV or anti-HIV ½
• History of diabetic ketoacidosis or hyperosmolar coma
• Subjects with known coronary artery disease or coronary revascularisation
• Subjects with previous history of cerebrovascular accident
• Subjects with known proliferative retinopathy or previous laser treatment for diabetic retinopathy
• Subjects with life-threatening conditions including malignancy
• Subjects with known psychiatric conditions including depression
• Subjects with significant renal impairment (eGFR<60ml/min at baseline) or non-diabetic renal disease (e.g. biopsy-proven glomerulonephritis or obstructive uropathy)
• Subjects with major physical disability

Adults of either sex with various stages of impaired fasting glucose tolerance levels and diabetes (with or without complications) will be considered as study population.