Heart Rate and Heart Rate Variability: Simplified

July 21, 2023

What is heart rate?

Heart rate is the number of times your heart beats per minute (beats/min or BPM). It provides valuable information about your overall health and fitness level.

Why is it important to track heart rate?

1. Identify health risks

Irregular heart rates could be warning signs of an underlying medical condition such as hypertension, arrhythmia, or heart disease. Regular tracking can help spot these conditions at an early stage and prevent serious health problems.

2. Stress management

During stress, heart rate tends to increase. By tracking heart rate at different hours of the day, you can identify times when you are feeling more stressed than usual, and take necessary steps to manage it.

3. Optimize exercise routines

Measuring heart rate while running or working out can give you a good idea of how hard you’re working yourself. If your heart rate is too high or low, it is a clear sign to adjust your intensity and optimize your performance.

How to measure heart rate on Eka?

Step 1: Allow camera access

Eka calculates your heart rate by detecting the blood flow in your finger when it is placed on the device’s back camera.

Step 2: Place your finger on the back camera

Press your finger gently against the back camera of your device until your screen becomes red.

If your device has multiple cameras, move your finger around each camera to find the correct back camera.

Step 3: Hold steady till measurement completes

Once your finger is detected, don’t move your hand or device till the measurement completes.

Step 4: Record your body state

Mention what you were doing while measuring your heart rate to better understand how healthy your heart rate is. In certain instances, heart rate can be impacted by the position of the body or the method of measurement.

Tips to get accurate heart rate readings

Eka uses photoplethysmography (PPG) principle to measure your heart rate and HRV. The device's camera measures the light absorbed by your finger and captures the changes in blood volume in your finger. This signal that is captured by the device helps to accurately determine your heart rate.

Accuracy of heart rate measurements can be affected by factors such as:

  • Pressure applied by finger
  • Movement
  • Temperature
  • Lighting

To get accurate readings, ensure you do the following:

  1. Apply gentle pressure with your finger. Pressing too hard could affect the blood flow.
  2. Make sure there’s no clothing or accessories obstructing the sensor on your device.
  3. If your device case is covering your camera region, remove it before taking the measurement.
  4. Check to see if your flash light is on to get adequate lighting and make the screen look bright red.
  5. Hold the phone with the same hand of the finger placed on the camera to avoid unnecessary movement.
  6. Do not talk or move your body while measuring.
  7. Rub your hands to make them warm.
  8. After placing your finger properly, if the screen is still not bright red, move to a well-light area.

After each time you measure your heart rate on Eka, you will see a score that indicates how good and dependable your reading was. You can trust this score to determine the accuracy of your reading.

What is heart rate variability (HRV)?

HRV is a way to measure how your heart beats, and it can tell you a lot about your body and overall health. Say you measure your heart rate, and you get a reading of 60 beats/min. Does this mean that your heart was beating once every second? Broadly YES. But at a more granular level, this is not entirely true.

Our heart rate does not beat at the same speed all the time. That would sound robotic like a metronome.

In humans, there is a slight variation in heart rate because the body is constantly adapting to changes - both internal and external. The variation in time between contractions or pumping of the heart for a given heart rate is called heart rate variability or HRV.

Heart Rate Variability or HRV

By tracking your HRV, you can gain insights into your body's stress levels, energy levels and overall health.

The autonomic nervous system (ANS) is a part of your body that helps you do things without thinking about it. It controls things like your heart beating, breathing, and digestion.

How Autonomic Nervous System (ANS) influences Heart Rate Variability (HRV)

ANS is responsible for managing how your body reacts to both internal and external factors. The ANS is made up of two main parts: sympathetic nervous system (SNS) and parasympathetic nervous system (PNS).

Sympathetic Nervous System (SNS)

The sympathetic nervous system is like your body's gas pedal. When you need to do something exciting or stressful, like running away from a scary dog or taking a test, it kicks in and helps you out. Your heart rate speeds up, your breathing gets faster, and your muscles get ready to act quickly. This is sometimes called the "fight or flight" response.

Parasympathetic Nervous System (PNS)

On the other hand, the parasympathetic nervous system is like your body's brake pedal. When you're feeling calm and relaxed, like when you're snuggled up in bed or reading a book, it helps slow everything down. Your heart rate slows down, your breathing gets slower and deeper, and your muscles relax. This is sometimes called the "rest and digest" response.

HRV is a way to measure the balance between your SNS and PNS that indicates overall body health.

💡 Important note: It's natural for your HRV to vary throughout the day and year as there are many factors that affect your ANS. Remember, your HRV is specific to you. So don’t worry if it’s different from others.

Factors that affect ANS which regulates heart rate variability

What is a normal heart rate variability?

There is no single "normal" HRV value that applies to everyone. What’s “normal” can vary person to person depending on factors such as their age, gender, physical fitness, and overall health.

In general, higher HRV is considered better as it suggests that the body can adapt to stress and environmental changes more easily.

Conversely, lower HRV is often linked to poorer health and increased chances of health risks.

According to studies, the normal HRV for an adult while resting lies anywhere between 20-200 milliseconds (ms). However, this can vary a lot depending on the person, and some people can still be healthy even if their HRV is outside this range.

The best way to determine your normal level is to track it over time. One HRV measurement may not be enough to tell what your normal HRV looks like or represent your overall health.

My HRV looks like a downward trend - what does it mean?

Declining heart rate variability (HRV) could indicate increased stress or other factors that affect the autonomic nervous system (ANS). That said, HRV changes can arise from various factors, so interpreting results requires considering the overall context.

Some common factors that influence HRV include:

  • Stress: Whether chronic or acute, stress can lower HRV by hindering the body's stress-response mechanisms.
  • Poor sleep: Inadequate or poor-quality sleep can affect HRV since sleep is a crucial recovery period for the body.
  • Sedentary lifestyle: Regular exercise improves HRV, so insufficient physical activity can negatively impact HRV.
  • Unhealthy diet: Consuming processed foods, high-sugar or high-fat diets can cause inflammation in the body, which can harm HRV.

My HRV looks like an upward trend - what does it mean?

If your heart rate variability (HRV) increases over time, it may mean that your body is becoming more resilient and better equipped to handle stress and other factors that affect your autonomic nervous system (ANS), which regulates HRV.

This could suggest that you are making positive changes in your lifestyle, such as exercising regularly, eating a healthy diet, and managing stress better.

Several factors can potentially boost HRV, including:

  • Exercise: Regular physical activity has been shown to enhance HRV by strengthening the cardiovascular system and promoting overall health.
  • Balanced diet: Consuming whole foods, fruits, vegetables, lean protein, and healthy fats may help reduce inflammation in the body and, therefore, enhance HRV.
  • Adequate sleep: Sufficient high-quality sleep is crucial for HRV, as it is a critical time for the body to rest and recover.
  • Stress reduction: Employing techniques such as meditation, deep breathing, or yoga can help lower stress levels and improve HRV.