Get HRV Measures

Get HRV Measures

Guided HRV measurements recorded in the Nolio app (Bluetooth chest strap or finger sensor): full beat-to-beat detail with time-domain and frequency-domain indices, and optionally the raw RR intervals.

This data only exists for in-app measurements — connected wearables never expose beat-to-beat RR intervals. For a single daily RMSSD index across all sources, use Get HRV RMSSD instead.

Endpoint:

• /get/hrv/measures/
• HTTP Method: GET

Parameters

Parameter	Required	Type	Description
from	no	string	Start date (inclusive), format YYYY-MM-DD. If omitted, defaults to a 90-day window ending at to (or at today if to is also omitted)
to	no	string	End date (inclusive), format YYYY-MM-DD
limit	no	int	Maximum number of measurements returned (default 15; max 366, or 31 when with_raw=true)
with_raw	no	bool	true to include the raw RR intervals (raw_rrs). Heavy payload — omitted by default
athlete_id	no	int	For coaches: retrieve data of a managed athlete. You can retrieve the ids with the Get Athletes route

Results are ordered most recent first.

Examples

Last HRV measurements (last 90 days by default):
https://www.nolio.io/api/get/hrv/measures/

Measurements over a date range, with raw RR intervals:
https://www.nolio.io/api/get/hrv/measures/?from=2025-01-01&to=2025-03-31&with_raw=true

Measurements of a managed athlete (coach access):
https://www.nolio.io/api/get/hrv/measures/?athlete_id=456

Returns

A JSON array of HRV measurement objects (most recent first). All index fields are floats and may be null if not computed.

Field	Type	Description
id	int	Measurement ID
date	string	Date of the measurement (YYYY-MM-DD)
hour	string	Start time of the measurement (HH:MM)
rmssd	float or null	Root Mean Square of Successive Differences (ms)
sdnn	float or null	Standard deviation of NN intervals (ms)
pnn50	float or null	% of successive RR differences greater than 50 ms
hr_mean	float or null	Mean heart rate (bpm)
rr_mean	float or null	Mean RR interval (ms)
serenity	float or null	Nolio serenity index
total_power	float or null	Total spectral power (ms²)
lf_power	float or null	Low-frequency power, as % of total power
hf_power	float or null	High-frequency power, as % of total power
ratio_lf_hf	float or null	LF/HF ratio
measure_method	string	ble (Bluetooth chest strap) or finger (finger sensor)
device_name	string or null	Name of the recording device, if known
raw_rrs	array of int	Raw RR intervals (ms). Only present when with_raw=true

Example response

[
  {
    "id": 44021,
    "date": "2025-06-15",
    "hour": "07:12",
    "rmssd": 52.3,
    "sdnn": 61.8,
    "pnn50": 18.4,
    "hr_mean": 54.1,
    "rr_mean": 1109.0,
    "serenity": 72.0,
    "total_power": 3120.0,
    "lf_power": 41.2,
    "hf_power": 38.7,
    "ratio_lf_hf": 1.06,
    "measure_method": "ble",
    "device_name": "Polar H10",
    "raw_rrs": [1102, 1115, 1098, 1121]
  }
]

Overlap with Get HRV RMSSD: each in-app measurement also surfaces as a single RMSSD value in Get HRV RMSSD with source = nolio_hrv.

Errors

• 400 - Invalid date format for from or to
• 403 - Invalid athlete_id (malformed value), or you are not allowed to access that managed athlete