Metrics

Energy Balance

The Energy Balance metric reflects the balance between recovery and physiological stress, encompassing both physical and mental aspects. It is based on the relative difference in activity of the Parasympathetic Nervous System (PNS) and the Sympathetic Nervous System (SNS), which together form the Autonomic Nervous System (ANS).
The ANS is responsible for regulating many of the body’s involuntary functions, such as heart rate, blood pressure, and digestion. It also influences emotional self-control and executive functioning, and triggers the “fight-or-flight” response during stress. Because of this, the autonomic nervous system can be easily overloaded, resulting in a variety of symptoms, including anxiety, insomnia, and gastrointestinal problems. 
The Energy Balance represents the relative balance of the ANS and helps the user to better understand the current state of the body and determine the best course of action and activity towards reaching certain goals without working against yourself.
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How is it calculated?
The Energy Balance results from the calculation of the PNS and SNS indices. The starting point for the calculation of these two indices is the photoplethysmogram signal (PPG signal) acquired from the face. The PNS index is based on the following parameters (compared to their normal population values):
Mean RR interval;
Root mean square of successive RR interval differences (RMSSD);
Poincaré plot index SD1 in normalized units.
The SNS index, on the other hand, is calculated using the following parameters:
Mean HR interval;
Baevsky's stress index (SI);
Poincaré plot index SD2 in normalized units.
When is it available?
Users must complete at least two Health Checks within one week to obtain an initial reading. The first result will be available the day after the second Health Check.
How can it be used? 
Our overall wellbeing and feeling of mental resilience is generally regulated by our ANS. Many studies show a good correlation between an ANS balance shift towards SNS and cardiovascular diseases (CVD) and mental health issues.
Leveraging the Energy Balance metric holds significant therapeutic benefits, allowing for tailored wellbeing interventions aimed at restoring this balance. By doing so, a more personalized and effective feedback mechanism can be achieved. Furthermore, individuals facing elevated or chronic mental health challenges may encounter difficulties in reducing the SNS activity and require additional active training or support. Addressing these nuances can substantially enhance the overall efficiency of therapy.
When an energy imbalance is detected, this is the starting point of personalised feedback to take action. Detect underlying issues through a short questionnaire, connect with a therapist or other healthcare provider, recommend stress management modules and/or guide the user to relevant platform content/offerings. 
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Interpreting results
The Energy Balance is returned as an integer on a scale of -5 to 5 and can be requested as a Widget﻿ or via the Rest API﻿.
Output 
(no specified unit)
Definition
Example Color Indicator
Example User Text
(-5) and (-4)
Strong imbalance towards SNS activity.
Red
Your Energy Balance indicates a greater dominance of the sympathetic branch, which is associated with the "fight or flight" response. The body is experiencing deeper levels of stress or fatigue. To avoid over training or over stressing it is highly recommended to prioritize rest.
(-3)
Moderate imbalance towards SNS activity.
Yellow
Your Energy Balance indicates a greater dominance of the sympathetic branch, which is associated with the "fight or flight" response. Indicates greater than usual stress (from all sources). Energy levels may be elevated. For long term results, consider lighter exercise and/or reducing stressful activities.
(-2), (-1), 0, 1 and 2
Relatively balanced PNS and SNS.
Green
Your Energy Balance indicates the balance between recovery and physiological stress (both physical and mental). The body is typically the most flexible and capable when the Energy Balance is in equilibrum.
3
Moderate imbalance towards PNS activity.
Green
Your Energy Balance indicates a greater dominance of the parasympathetic branch, which is associated with the "rest and digest" response. Recovery activity is slightly elevated. Energy levels may be lower. This state is often correlated with overreaching in training or fighting off mild or early illness.
4 and 5
Strong relative PNS activity.
Yellow
Your Energy Balance indicates a greater dominance of the parasympathetic branch, which is associated with the "rest and digest" response. Indicates excessive recovery activity, often in response to cumulative stress or elevated immune system activity.

Output (no specified unit)	Definition	Example Color Indicator	Example User Text
(-5) and (-4)	Strong imbalance towards SNS activity.	Red	Your Energy Balance indicates a greater dominance of the sympathetic branch, which is associated with the "fight or flight" response. The body is experiencing deeper levels of stress or fatigue. To avoid over training or over stressing it is highly recommended to prioritize rest.
(-3)	Moderate imbalance towards SNS activity.	Yellow	Your Energy Balance indicates a greater dominance of the sympathetic branch, which is associated with the "fight or flight" response. Indicates greater than usual stress (from all sources). Energy levels may be elevated. For long term results, consider lighter exercise and/or reducing stressful activities.
(-2), (-1), 0, 1 and 2	Relatively balanced PNS and SNS.	Green	Your Energy Balance indicates the balance between recovery and physiological stress (both physical and mental). The body is typically the most flexible and capable when the Energy Balance is in equilibrum.
3	Moderate imbalance towards PNS activity.	Green	Your Energy Balance indicates a greater dominance of the parasympathetic branch, which is associated with the "rest and digest" response. Recovery activity is slightly elevated. Energy levels may be lower. This state is often correlated with overreaching in training or fighting off mild or early illness.
4 and 5	Strong relative PNS activity.	Yellow	Your Energy Balance indicates a greater dominance of the parasympathetic branch, which is associated with the "rest and digest" response. Indicates excessive recovery activity, often in response to cumulative stress or elevated immune system activity.

Mental Health Risk

Sleep Quality