COVID-19 and health indicators: HRV and blood oxygen level

Heart rate variability (HRV for short) is a general indicator of your autonomic system’s state that reflects your heart. HRV measurement is a relatively objective metric of your physical and psycho-emotional condition, from which you can conclude the readiness of your body to be active.

Scientists at Stanford University have made an important discovery. They found that people with the COVID-19 viral infection had reduced heart rate variability. A single nasal or blood test for antibodies is unlikely to guarantee a timely diagnosis. But when you continuously wear an Apple Watch that monitors your health, it’s much better and safer.

What is heart rate variability?

HRV is the amount of time that the heart muscle contracts. Because the heartbeat is uneven, 60 beats per minute do not indicate a uniform every second contraction. Within a minute of measurement, the time distance between strokes can fluctuate, and this variability indicates your condition.

A series of cardio intervals (NN, i.e., Normal –to-Normal) is not a random set of numbers. It is a complex structure that reflects the regulatory effect on the sinus node of the heart of the autonomic nervous system and various humoral influences. That is why a complete analysis of the sinusoidal diagram on a heart rate variability monitor provides essential information about the state of the autonomic regulation of the cardiovascular system of the body.

Measurements of heart rate variability

Why do you need an analysis of HRV indicators?

– To determine the balance of the autonomic system and neurohumoral regulation;

– The ability to assess the severity of the body’s adaptability and response to external stimuli, such as stress;

– Analysis of individual areas of autonomic regulation of blood circulation;

Collection and analysis of the obtained data are useful for understanding and further developing forecasts based on the current functional state of the organism, severity, and adaptive response to external irritants. You can use your phone as a heart rate measuring device (HRM sensor). 

How to check HRV on iPhone?

For example, the phone uses its camera and a bright flash to illuminate the tissues on the fingertip and record the nature of blood flow. Apple Watch monitors the parameters of the pulse wave through a touch sensor. The heart contracts and the blood enter the artery and then distributes throughout the body, and the clock sensor on the wrist registers the time intervals and the force with which the blood flows. Welltory collects all data on blood pressure, heart rate variability, pulse, and blood oxygen saturation and analyzes them thanks to a sophisticated algorithm that works on the principle of self-learning and AI.

Oxygen level

The level of arterial blood oxygen directly affects the work of the heart and brain. Its status in a healthy person’s blood should be in the range of 95-99%. People with various lung diseases and cardiovascular insufficiency have a lower rate of these indicators, namely – 92-94%. Any respiratory failure reduces saturation, and therefore the level of oxygen in the blood for such people will not be a critical indicator and diagnostic criterion. Low levels of saturation in the average person can cause hospitalization.

Blood oxygen through the Covid-19

In a COVID-19 pandemic, the level of saturation may be an indicator of coronavirus infection. That is why most specialists recommend having a pulse oximeter for measuring oxygen levels diagnosis as a rational replacement for regular monitoring of complex equipment in the hospital. If there is a decrease in blood oxygen content to 92% and below – the specialist should provide emergency medical care. In such conditions, doctors conduct oxygen therapy and complete the diagnosis of the body.

In the circumstances, if you cannot check the oxygen in the blood, the doctor needs to ask you in all details about your condition and symptoms: obsessive dry cough, shortness of breath, difficulty breathing, and chest pain, how easily the temperature drops, and how you feel when pronounced lethargy.

The doctor will draw conclusions based on the conversation with you and advise whether to go to the clinic and do it yourself or call an ambulance. If you are 37.5 and generally feel normal, your task is to stay home, protect others from infection, if necessary, bring down the temperature, drink plenty of fluids and keep in touch with your doctor in the format you agree.

Blood oxygen control and measuring

The rate of reduction

The oxygen content can decrease for various reasons, and therefore the speed is different in each case. The decrease can occur for hours or days. Sometimes the drop in oxygen levels is 1-2% during the day. If thrombosis occurs in the pulmonary artery, the oxygen level may drop to critical in a matter of minutes. To control saturation, use pulse oximeters or special applications for smartphones.

Pulse oximetry is the most convenient method of monitoring patients in many settings, especially with limited funding. It allows a particular skill to assess several parameters of the patient’s condition, namely his pulse and blood saturation.

Pulse oximeter

To measure the blood’s oxygen level, you need to place a pulse oximeter on the end phalanx of the finger of the dominant hand. Most doctors place it on the index finger. Then press the button and wait a few seconds. Two numbers will appear on the screen – the top will show the percentage of oxygen in the blood, and the bottom – the heart rate. It is better to measure saturation sitting or lying down. The hand should lie relaxed, and the patient better place it evenly on a table or bed.

The pulse oximeter is not always accurate. In addition to the device’s technical problems, the cause of the error may be improper preparation of the person to measure oxygen in the blood. The pulse oximeter may show low saturation after exercise or strenuous work. The device will also show you a false result if the patient’s hand is cold and a narrowing of blood vessels. If the nails are damaged or covered with gel polish, it will affect the rate. You can also use the proper application. Just fill in the AppStore search line “blood oxygen monitor app,” and you will find what you need.