Biomarkers | Sahha Docs

DashboardsChallengesAnalytics/BIMonitoring

Introduction

Clean, standardized health metrics from any source. Sahha collects raw data from smartphones and wearables, deduplicates it, and outputs 100+ biomarkers across sleep, activity, vitals, body composition, nutrition, and engagement.

Key Features

Real-time

Updates within 1 minute—always current data for your users

Deduplicated

Multiple sources merged intelligently—no double-counting steps

Standardized

Consistent units and formats across all devices and platforms

Comprehensive

100+ metrics across sleep, activity, vitals, body, nutrition, and engagement

Derived Metrics

Proprietary biomarkers like sleep debt and activity regularity

Flexible Access

Query via API on-demand or stream via webhooks in real-time

How It Works

Raw health data flows in from HealthKit, Health Connect, and wearables. Sahha cleans, deduplicates, and normalizes this data into standardized biomarkers—each with consistent units, aggregation methods, and update frequencies.

The pipeline:

Collect — Raw samples from multiple sources
Deduplicate — Remove overlapping records
Aggregate — Daily totals, averages, or point-in-time values
Deliver — Via API or webhooks in real-time

List of Biomarkers

Activity

steps

Total number of steps taken

Unit: count
ValueType: long
Periodicity: daily
Aggregation: total

Primary measure of daily movement. Powers step goals, activity challenges, and movement trend analysis.

floors_climbed

Total number of floors climbed

Unit: count
ValueType: long
Periodicity: daily
Aggregation: total

Tracks vertical movement and stair climbing. Useful for intensity detection and urban mobility patterns.

active_hours

Hours with any physical activity

Unit: hour
ValueType: double
Periodicity: daily
Aggregation: total

Measures movement distribution throughout the day. Helps identify sedentary patterns and hourly activity goals.

active_duration

Total duration of all physical activities

Unit: minute
ValueType: long
Periodicity: daily
Aggregation: total

Overall activity time regardless of intensity. Core metric for daily activity targets and weekly summaries.

activity_low_intensity_duration

Duration in low-intensity activities (1.5-2.9 METs)

Unit: minute
ValueType: long
Periodicity: daily
Aggregation: total

Light movement like slow walking. Useful for tracking non-exercise activity and reducing sedentary time.

activity_medium_intensity_duration

Duration in moderate-intensity activities (3-5.9 METs)

Unit: minute
ValueType: long
Periodicity: daily
Aggregation: total

Brisk walking, light exercise. Key for meeting health guidelines (150 min/week moderate activity).

activity_high_intensity_duration

Time in high-intensity activities (>6 METs)

Unit: minute
ValueType: long
Periodicity: daily
Aggregation: total

Vigorous exercise and workouts. Powers exercise tracking, workout detection, and fitness programs.

activity_sedentary_duration

Time spent inactive

Unit: minute
ValueType: long
Periodicity: daily
Aggregation: total

Tracks prolonged sitting and inactivity. Essential for sedentary alerts and movement reminders.

active_energy_burned

Energy expended during active phases

Unit: kcal
ValueType: double
Periodicity: daily
Aggregation: total

Calories burned through movement. Core metric for calorie tracking, weight management, and energy balance.

total_energy_burned

Overall energy expenditure

Unit: kcal
ValueType: double
Periodicity: daily
Aggregation: total

Combined resting and active calories. Useful for total daily energy expenditure (TDEE) calculations.

Body

height

Measure of the individual's stature

Unit: meter
ValueType: double
Periodicity: none
Aggregation: none

Static measurement used for BMI calculation and personalizing health targets.

weight

Total body mass

Unit: kilogram
ValueType: double
Periodicity: none
Aggregation: none

Foundational health metric. Powers weight tracking, goal setting, and trend visualization.

body_mass_index

Body fat computation from weight and height

Unit: kg/m²
ValueType: double
Periodicity: none
Aggregation: none

Standard body composition indicator. Useful for health assessments and population comparisons.

body_fat

Proportion of body weight that is fat

Requires wearable device

Unit: percentage
ValueType: double
Periodicity: none
Aggregation: none

More accurate than BMI for body composition. Key metric for fitness and body recomposition goals.

fat_mass

Total weight of fat in the body

Requires wearable device

Unit: kilogram
ValueType: double
Periodicity: none
Aggregation: none

Absolute fat measurement. Useful for tracking fat loss while preserving muscle mass.

lean_mass

Weight of non-fat body components

Requires wearable device

Unit: kilogram
ValueType: double
Periodicity: none
Aggregation: none

Muscle, bone, and organ mass. Important for strength training and metabolic health tracking.

waist_circumference

Circumference measurement around waist

Unit: meter
ValueType: double
Periodicity: none
Aggregation: none

Indicator of abdominal fat distribution. Often more predictive than BMI for health risks.

resting_energy_burned

Energy expended at rest

Unit: kcal
ValueType: double
Periodicity: daily
Aggregation: total

Basal metabolic rate estimate. Foundation for calorie budgets and nutrition planning.

Engagement

app_sessions

Total number of app sessions opened

Unit: count
ValueType: long
Periodicity: daily
Aggregation: total

App open frequency. Core engagement metric for retention analysis and feature adoption.

app_session_duration

Total time spent across all app sessions

Unit: second
ValueType: long
Periodicity: daily
Aggregation: total

Daily app usage time. Measures user investment and content engagement.

app_session_average_duration

Average duration of each app session

Unit: second
ValueType: double
Periodicity: daily
Aggregation: average

Typical session length. Indicates content depth and user attention patterns.

Nutrition

energy_intake

Total energy consumed from food and beverages

Unit: kcal
ValueType: double
Periodicity: daily
Aggregation: total

Core nutrition metric. Foundation for calorie tracking, weight management, and energy balance against active and resting expenditure.

water_intake

Total water consumed

Unit: liter
ValueType: double
Periodicity: daily
Aggregation: total

Hydration tracking. Useful for hydration goals, sports performance, and identifying intake patterns.

protein_intake

Total protein consumed

Unit: gram
ValueType: double
Periodicity: daily
Aggregation: total

Macronutrient for muscle maintenance, recovery, and satiety. Key metric for athletes and body composition goals.

fat_intake

Total dietary fat consumed

Unit: gram
ValueType: double
Periodicity: daily
Aggregation: total

Macronutrient providing essential fatty acids and energy. Important for hormone production and nutrient absorption.

fat_saturated_intake

Total saturated fat consumed

Unit: gram
ValueType: double
Periodicity: daily
Aggregation: total

Subtype of dietary fat. Tracked against guidelines for cardiovascular health.

fat_monounsaturated_intake

Total monounsaturated fat consumed

Unit: gram
ValueType: double
Periodicity: daily
Aggregation: total

Heart-healthy fats found in olive oil, nuts, and avocado. Associated with improved cardiovascular markers.

fat_polyunsaturated_intake

Total polyunsaturated fat consumed

Unit: gram
ValueType: double
Periodicity: daily
Aggregation: total

Includes omega-3 and omega-6 fatty acids. Essential for cell membrane health and inflammation regulation.

fat_trans_intake

Total trans fat consumed (Android only)

Unit: gram
ValueType: double
Periodicity: daily
Aggregation: total

Industrial trans fats are linked to cardiovascular risk. Most health guidelines recommend minimising intake.

cholesterol_intake

Total dietary cholesterol consumed

Unit: milligram
ValueType: double
Periodicity: daily
Aggregation: total

Dietary cholesterol contributes to blood lipid profiles. Relevant for cardiovascular risk assessment.

carbohydrate_intake

Total carbohydrates consumed

Unit: gram
ValueType: double
Periodicity: daily
Aggregation: total

Primary energy macronutrient. Core metric for endurance fueling, glycemic control, and macronutrient ratio tracking.

sugar_intake

Total sugars consumed

Unit: gram
ValueType: double
Periodicity: daily
Aggregation: total

Subset of carbohydrates. Tracked for blood glucose management, dental health, and dietary guideline adherence.

fiber_intake

Total dietary fiber consumed

Unit: gram
ValueType: double
Periodicity: daily
Aggregation: total

Supports digestive health, satiety, and metabolic regulation. Most adults under-consume the recommended intake.

vitamin_a_intake

Total vitamin A consumed

Unit: microgram
ValueType: double
Periodicity: daily
Aggregation: total

Fat-soluble vitamin essential for vision, immune function, and skin health.

vitamin_c_intake

Total vitamin C consumed

Unit: milligram
ValueType: double
Periodicity: daily
Aggregation: total

Water-soluble antioxidant. Supports immune function, collagen synthesis, and iron absorption.

vitamin_d_intake

Total vitamin D consumed

Unit: microgram
ValueType: double
Periodicity: daily
Aggregation: total

Critical for bone health, immune function, and mood. Frequently insufficient in low-sunlight regions.

vitamin_e_intake

Total vitamin E consumed

Unit: milligram
ValueType: double
Periodicity: daily
Aggregation: total

Fat-soluble antioxidant. Helps protect cells from oxidative stress.

vitamin_k_intake

Total vitamin K consumed

Unit: microgram
ValueType: double
Periodicity: daily
Aggregation: total

Essential for blood clotting and bone metabolism.

thiamin_intake

Total thiamin (vitamin B1) consumed

Unit: milligram
ValueType: double
Periodicity: daily
Aggregation: total

Supports energy metabolism and nervous system function.

riboflavin_intake

Total riboflavin (vitamin B2) consumed

Unit: milligram
ValueType: double
Periodicity: daily
Aggregation: total

Involved in energy production and cellular function.

niacin_intake

Total niacin (vitamin B3) consumed

Unit: milligram
ValueType: double
Periodicity: daily
Aggregation: total

Important for DNA repair, metabolism, and skin/nerve health.

pantothenic_acid_intake

Total pantothenic acid (vitamin B5) consumed

Unit: milligram
ValueType: double
Periodicity: daily
Aggregation: total

Required for synthesising coenzyme A and metabolising fats, carbohydrates, and proteins.

vitamin_b6_intake

Total vitamin B6 consumed

Unit: milligram
ValueType: double
Periodicity: daily
Aggregation: total

Supports amino acid metabolism, neurotransmitter synthesis, and immune function.

biotin_intake

Total biotin (vitamin B7) consumed

Unit: microgram
ValueType: double
Periodicity: daily
Aggregation: total

Supports metabolism of fats, carbohydrates, and proteins; commonly associated with hair and skin health.

folate_intake

Total folate (vitamin B9) consumed

Unit: microgram
ValueType: double
Periodicity: daily
Aggregation: total

Critical for DNA synthesis and red blood cell formation. Especially important before and during pregnancy.

vitamin_b12_intake

Total vitamin B12 consumed

Unit: microgram
ValueType: double
Periodicity: daily
Aggregation: total

Essential for red blood cell formation and nervous system health. Often supplemented in plant-based diets.

calcium_intake

Total calcium consumed

Unit: milligram
ValueType: double
Periodicity: daily
Aggregation: total

Primary mineral for bone and dental health. Also supports muscle contraction and nerve signalling.

iron_intake

Total iron consumed

Unit: milligram
ValueType: double
Periodicity: daily
Aggregation: total

Required for oxygen transport in blood. Common deficiency, particularly in menstruating individuals.

magnesium_intake

Total magnesium consumed

Unit: milligram
ValueType: double
Periodicity: daily
Aggregation: total

Involved in over 300 enzymatic reactions. Supports muscle function, sleep, and energy production.

phosphorus_intake

Total phosphorus consumed

Unit: milligram
ValueType: double
Periodicity: daily
Aggregation: total

Works with calcium to build bone; also a component of ATP and cell membranes.

potassium_intake

Total potassium consumed

Unit: milligram
ValueType: double
Periodicity: daily
Aggregation: total

Regulates fluid balance, blood pressure, and muscle/nerve function.

sodium_intake

Total sodium consumed

Unit: milligram
ValueType: double
Periodicity: daily
Aggregation: total

Regulates fluid balance and blood pressure. Often tracked to stay within cardiovascular health guidelines.

zinc_intake

Total zinc consumed

Unit: milligram
ValueType: double
Periodicity: daily
Aggregation: total

Supports immune function, wound healing, and protein synthesis.

chloride_intake

Total chloride consumed

Unit: milligram
ValueType: double
Periodicity: daily
Aggregation: total

Electrolyte that works with sodium to maintain fluid balance and pH.

copper_intake

Total copper consumed

Unit: milligram
ValueType: double
Periodicity: daily
Aggregation: total

Required for iron metabolism, connective tissue, and antioxidant defence.

manganese_intake

Total manganese consumed

Unit: milligram
ValueType: double
Periodicity: daily
Aggregation: total

Trace mineral involved in bone formation and metabolism of amino acids and carbohydrates.

chromium_intake

Total chromium consumed

Unit: microgram
ValueType: double
Periodicity: daily
Aggregation: total

Trace mineral that enhances insulin action and supports macronutrient metabolism.

molybdenum_intake

Total molybdenum consumed

Unit: microgram
ValueType: double
Periodicity: daily
Aggregation: total

Cofactor for enzymes that break down sulfites and toxic byproducts.

selenium_intake

Total selenium consumed

Unit: microgram
ValueType: double
Periodicity: daily
Aggregation: total

Antioxidant trace mineral. Supports thyroid function and immune health.

iodine_intake

Total iodine consumed

Unit: microgram
ValueType: double
Periodicity: daily
Aggregation: total

Essential for thyroid hormone production and metabolic regulation.

caffeine_intake

Total caffeine consumed

Unit: milligram
ValueType: double
Periodicity: daily
Aggregation: total

Stimulant affecting alertness, sleep, and cardiovascular response. Useful for sleep hygiene and performance tracking.

Sleep

sleep_start_time

Time when individual falls asleep

Unit: datetime
ValueType: datetime
Periodicity: daily
Aggregation: none

Tracks bedtime patterns. Useful for sleep schedule consistency and circadian rhythm analysis.

sleep_mid_time

Midpoint time in the sleep cycle

Unit: datetime
ValueType: datetime
Periodicity: daily
Aggregation: none

Center of the sleep window. Key metric for chronotype detection (early bird vs night owl).

sleep_end_time

Time when individual wakes up

Unit: datetime
ValueType: datetime
Periodicity: daily
Aggregation: none

Tracks wake time patterns. Powers alarm optimization and morning routine features.

sleep_duration

Total time spent sleeping

Unit: minute
ValueType: long
Periodicity: daily
Aggregation: total

Core sleep metric. Essential for sleep goals, trend analysis, and health recommendations.

sleep_debt

Discrepancy between required and actual sleep

Unit: hour
ValueType: double
Periodicity: weekly
Aggregation: average

Cumulative sleep deficit. Useful for recovery recommendations and explaining fatigue patterns.

sleep_interruptions

Count of awakenings during night

Requires wearable device

Unit: count
ValueType: long
Periodicity: daily
Aggregation: total

Measures sleep fragmentation. Higher counts may indicate environmental issues or sleep disorders.

sleep_in_bed_duration

Total time spent in bed

Unit: minute
ValueType: long
Periodicity: daily
Aggregation: total

Time in bed vs actual sleep. Used to calculate sleep efficiency and detect insomnia patterns.

sleep_awake_duration

Time awake after initially falling asleep

Requires wearable device

Unit: minute
ValueType: long
Periodicity: daily
Aggregation: total

Measures mid-sleep wakefulness. Indicator of sleep maintenance and restlessness.

sleep_light_duration

Time spent in light sleep phase

Requires wearable device

Unit: minute
ValueType: long
Periodicity: daily
Aggregation: total

Stage 1-2 sleep. Important for understanding sleep architecture and stage transitions.

sleep_rem_duration

Time spent in REM sleep phase

Requires wearable device

Unit: minute
ValueType: long
Periodicity: daily
Aggregation: total

Dream sleep phase linked to memory and learning. Key indicator of mental recovery.

sleep_deep_duration

Time spent in deep sleep phase

Requires wearable device

Unit: minute
ValueType: long
Periodicity: daily
Aggregation: total

Most restorative sleep stage. Key indicator of physical recovery and immune function.

sleep_regularity

Consistency of sleep patterns over time

Unit: index
ValueType: double
Periodicity: weekly
Aggregation: average

Measures schedule consistency. Regular sleep timing is linked to better sleep quality.

sleep_latency

Time to fall asleep after going to bed

Requires wearable device

Unit: minute
ValueType: long
Periodicity: daily
Aggregation: none

How quickly you fall asleep. Very short or long latency can indicate sleep issues.

sleep_efficiency

Ratio of sleep time to time in bed

Requires wearable device

Unit: percentage
ValueType: double
Periodicity: daily
Aggregation: none

Sleep quality indicator. Higher efficiency means more time asleep vs lying awake.

Vitals

heart_rate_resting

Heart rate when at rest

Requires wearable device

Unit: bpm
ValueType: long
Periodicity: daily
Aggregation: average

Baseline cardiovascular metric. Lower values generally indicate better fitness; trends show conditioning changes.

heart_rate_sleep

Average heart rate during sleep

Requires wearable device

Unit: bpm
ValueType: long
Periodicity: daily
Aggregation: average

Nighttime heart rate baseline. Useful for recovery assessment and detecting illness or overtraining.

heart_rate_variability_sdnn

Standard deviation of NN intervals

Requires wearable device

Unit: ms
ValueType: double
Periodicity: daily
Aggregation: average

Measure of autonomic nervous system balance. Higher values suggest better recovery and stress resilience.

heart_rate_variability_rmssd

Root mean square of successive differences

Requires wearable device

Unit: ms
ValueType: double
Periodicity: daily
Aggregation: average

Parasympathetic activity indicator. Key metric for readiness scores and recovery tracking.

respiratory_rate

Frequency of breaths per minute at rest

Requires wearable device

Unit: count/min
ValueType: double
Periodicity: daily
Aggregation: average

Baseline breathing rate. Deviations can indicate stress, illness, or respiratory issues.

respiratory_rate_sleep

Average respiratory rate during sleep

Requires wearable device

Unit: count/min
ValueType: double
Periodicity: daily
Aggregation: average

Nighttime breathing patterns. Useful for detecting sleep apnea indicators and illness onset.

oxygen_saturation

Proportion of oxygen-saturated hemoglobin

Requires wearable device

Unit: percentage
ValueType: double
Periodicity: daily
Aggregation: average

Blood oxygen level. Normal is 95-100%; lower values may indicate respiratory or circulation issues.

oxygen_saturation_sleep

Average oxygen saturation during sleep

Requires wearable device

Unit: percentage
ValueType: double
Periodicity: daily
Aggregation: average

Nighttime oxygen levels. Dips during sleep can indicate breathing disturbances.

vo2_max

Maximum oxygen utilization during exercise

Requires wearable device

Unit: mL/kg/min
ValueType: double
Periodicity: daily
Aggregation: average

Gold standard for cardio fitness. Higher values indicate better aerobic capacity and endurance.

blood_glucose

Level of glucose in blood

Requires wearable device

Unit: mg/dL
ValueType: double
Periodicity: daily
Aggregation: average

Blood sugar level. Essential for diabetes management, energy optimization, and metabolic health.

blood_pressure_systolic

Peak arterial pressure during heartbeats

Requires wearable device

Unit: mmHg
ValueType: long
Periodicity: daily
Aggregation: average

Top number in blood pressure. Key cardiovascular health indicator; track trends over time.

blood_pressure_diastolic

Lowest arterial pressure during heart relaxation

Requires wearable device

Unit: mmHg
ValueType: long
Periodicity: daily
Aggregation: average

Bottom number in blood pressure. Important for complete cardiovascular assessment.

body_temperature_basal

Body temperature at rest

Requires wearable device

Unit: celsius
ValueType: double
Periodicity: daily
Aggregation: average

Baseline body temperature. Deviations can indicate illness, ovulation, or circadian disruption.

skin_temperature_sleep

Skin temperature during sleep

Requires wearable device

Unit: celsius
ValueType: double
Periodicity: daily
Aggregation: average

Nighttime temperature patterns. Useful for sleep environment optimization and illness detection.

Browse our comprehensive data dictionary to view all available outputs beyond just biomarkers.

Output Schema

Every biomarker returns a consistent JSON structure with the value, unit, and time range.

id UUID

Idempotent identifier—updates replace the previous entry with the same id

type string

Biomarker type (e.g., steps, heart_rate_resting, sleep_duration)

category string

Category: activity, body, sleep, vitals, nutrition, engagement

value string

The measured or aggregated value

valueType string

Data type of the value: long, double, string, datetime

unit string

Unit of measurement (e.g., count, minute, bpm, percentage)

aggregation string

How the value was derived: total, average, minimum, maximum, none

periodicity string

Update frequency: daily, weekly, monthly, none

startDateTime datetime

Start of the measurement period (ISO 8601)

endDateTime datetime

End of the measurement period (ISO 8601)

createdAtUtc datetime

UTC timestamp when the entry was created

Example Response

JSON

{
	"id": "b7c8d9e0-f1a2-3456-bcde-f78901234567",
	"type": "steps",
	"category": "activity",
	"value": "8432",
	"valueType": "long",
	"unit": "count",
	"aggregation": "total",
	"periodicity": "daily",
	"startDateTime": "2024-09-03T00:00:00+05:00",
	"endDateTime": "2024-09-03T23:59:59+05:00",
	"createdAtUtc": "2024-09-04T05:30:00Z"
}

FAQ

How frequently are biomarkers updated? +

Biomarkers are updated based on their periodicity settings, which can be daily, weekly, or intraday.

Are wearable devices required to capture all biomarkers? +

While some biomarkers require wearable devices, others can be derived from different health data sources.

Getting Started

API

Query biomarkers on-demand by category or type

Webhooks

Receive biomarkers automatically as they're calculated

Support

For additional assistance or more detailed information on biomarkers, please contact support@sahha.ai or reach out in the slack community.