Understanding Health Data

Moodji summarizes your daily status based on your health data. You can also visualize your health data trends through Data Trends. But before diving in, it's helpful to understand what each data point means.

Heart Rate Variability (HRV)

HRV measures the variation in time intervals between consecutive heartbeats. It's an indicator of autonomic nervous system function, reflecting overall health and the body’s ability to adapt to stress. HRV can monitor personal health, guide lifestyle choices, and is used in sports performance and clinical settings.

High HRV indicates a well-functioning autonomic nervous system, meaning your body can effectively respond to stress and environmental changes with strong adaptability. People with higher HRV typically experience lower stress levels and greater well-being.

Low HRV usually indicates that the sympathetic nervous system is dominant, related to the "fight or flight" response. This may result from chronic stress, sleep deprivation, or health issues. Low HRV suggests the body struggles to adapt to stress and environmental changes and is associated with higher inflammation levels and various chronic diseases.

Respiratory Rate (RP)

Respiratory rate is the number of breaths taken per minute. It's an essential indicator of respiratory efficiency and overall respiratory health. A normal respiratory rate indicates healthy lung function, capable of providing adequate oxygen to the body and expelling carbon dioxide. Monitoring respiratory rate is crucial for identifying potential health issues and optimizing lifestyle choices.

A high respiratory rate (rapid breathing) may indicate underlying health issues, such as respiratory diseases, metabolic imbalances, or nervous system problems. A low respiratory rate (slow breathing) may result from suppressed respiratory drive, possibly due to certain medications or health conditions.

The normal respiratory rate for adults typically ranges from 12 to 20 breaths per minute. The recommended range may vary depending on age, health status, and other factors.

Blood Oxygen Saturation (SpO2)

Blood oxygen saturation measures the percentage of oxygen in the blood. It assesses respiratory health and oxygen supply, making it a vital health indicator.

High SpO2 indicates sufficient oxygen in the blood, typically suggesting good respiratory function. Low SpO2 may signal inadequate oxygen supply, potentially leading to fatigue, shortness of breath, or even organ damage.

A healthy blood oxygen saturation range is 95% to 100%.

Sleep Duration

Most adults need 7-9 hours of sleep each night, with an average of about 8 hours and 10 minutes.

It is recommended that deep sleep and REM sleep combined should total 3-4 hours.

Deep Sleep (Deep)

Deep sleep is the third and fourth stages of non-rapid eye movement (NREM) sleep, also known as slow-wave sleep or delta sleep. In this stage, the body is fully relaxed, heart rate and breathing slow down, muscles are completely relaxed, and brain wave activity significantly slows, predominantly showing delta waves. It’s difficult to be awakened, and if woken up, one may feel groggy and disoriented.

Deep sleep is crucial for physical recovery and repair. During this stage, the body undergoes tissue repair, bone and muscle growth, and immune system strengthening. It also helps consolidate memory and learning.

Adults typically need 1-2 hours of deep sleep, accounting for 13-23% of total sleep time.

Rapid Eye Movement Sleep (REM)

During the REM stage, the eyes move rapidly, brain wave activity approaches waking levels, breathing becomes quick and irregular, heart rate and blood pressure rise, and most muscles are temporarily paralyzed to prevent physical movement during dreams. Most dreaming occurs in this stage.

REM sleep is vital for cognitive functions like memory consolidation and emotional regulation.

Adults need around 2 hours of REM sleep, making up 20-25% of total sleep time.

Core Sleep (Core)

Core sleep is the first and second stages of non-rapid eye movement sleep (NREM), also known as light sleep. It refers to the stages of sleep that are neither REM nor Deep.

In this stage, muscle activity decreases, and body temperature drops, occupying most of a person's sleep time. Brain waves essential for cognition are generated during this stage.

Awake Time (Awake)

Throughout the night, there may be several brief periods of wakefulness, which is usually normal. In general, the duration of awake periods should be minimized to ensure high-quality sleep.

Sleep Heart Rate (SHR)

Sleep heart rate (SHR) refers to the number of heartbeats per minute during sleep. Lower numbers typically indicate a healthy, strong heart and good cardiovascular condition. If your sleep heart rate is trending downward, it indicates that you are becoming healthier. You can nurture your heart by gradually engaging in physical activities, managing your weight, and reducing daily stress.

Wrist Temperature

Wrist temperature is the fluctuation in body temperature data measured by the Apple Watch during sleep. It provides continuous monitoring of body temperature changes, helping to understand the body's health status and trends.

Temperature fluctuations may be related to menstrual cycles or changes in lifestyle habits. Persistent elevation may indicate potential infections or illnesses that require further investigation or medical attention.