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Biorhythm Cycles

Computes physical (23-day), emotional (28-day), and intellectual (33-day) biorhythm cycles for a birth date. Returns cycle values (-1.0 to +1.0), percentage, phase label (High/Rising/Falling/Low), and critical day flags. Critical days occur when a cycle crosses zero — these represent instability and vulnerability to poor judgment. Supports single-day and multi-day (up to 90 days) range requests. Formula: sin(2π × t / cycle_length) where t = days since birth. Source: Wilhelm Fliess (1897) physical cycle; Hermann Swoboda (1900) emotional cycle; Alfred Teltscher (1926) intellectual cycle.

Endpoint

POST /v1/western/biorhythm

Request parameters

FieldTypeRequiredDescription
birth_datestring (date)YesDate of birth in YYYY-MM-DD format.
target_datestring (date) | nullNoDate to compute cycles for. Defaults to today.
daysintegerNoNumber of consecutive days to compute (1-90). Use 1 for a single day snapshot. Use >1 for a date range.

Example request

curl -X POST "https://api.asterwise.com/v1/western/biorhythm" \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{"birth_date":"1985-11-12","target_date":"2026-01-01","days":1}'

Example response

{
"success": true,
"message": "success",
"data": {
"birth_date": "1985-11-12",
"target_date": "2026-01-01",
"days_since_birth": 14660,
"cycles": {
"physical": {
"value": 0.631088,
"percentage": 63.11,
"phase": "High",
"is_critical": false,
"cycle_length_days": 23,
"description": "Physical stamina, strength, coordination, and resilience. Source: Wilhelm Fliess (1897)."
},
"emotional": {
"value": -0.433884,
"percentage": -43.39,
"phase": "Falling",
"is_critical": false,
"cycle_length_days": 28,
"description": "Emotional sensitivity, creativity, mood, and awareness. Source: Hermann Swoboda (1900)."
},
"intellectual": {
"value": 0.998867,
"percentage": 99.89,
"phase": "High",
"is_critical": false,
"cycle_length_days": 33,
"description": "Analytical ability, logical thinking, and memory. Source: Alfred Teltscher (1926)."
}
},
"critical_today": [],
"has_critical_day": false,
"composite_score": 0.39869,
"note": "Biorhythm is a Western concept (Fliess/Swoboda). Vedic equivalent: Tarabala and Chandrabala measure daily auspiciousness…"
}
}

Response fields

FieldTypeDescription
successbooleanTrue if the request succeeded
messagestringHuman-readable status message
dataBiorhythmSingleDayResponse | BiorhythmRangeResponseThe endpoint response payload

Errors

CodeDescriptionReference
authentication_failedMissing or invalid API key.authentication_failed
ephemeris_unavailableUpstream ephemeris service error.ephemeris_unavailable
insufficient_tierAPI key tier does not include this endpoint.insufficient_tier
internal_errorUnexpected server error.internal_error
ip_rate_limit_exceededToo many requests in a short window.ip_rate_limit_exceeded
payload_too_largeRequest body exceeds the size limit.payload_too_large
resource_not_foundReferenced resource was not found.resource_not_found
validation_errorRequest body failed schema validation.validation_error