{"uid":"cap_imker24W_KujufjkzXEi0","slug":"saylor-innovations-heart-rate-zones-calculator-3d384dcb","name":"Saylor Innovations Heart Rate Zones Calculator","description":"Estimated maximum heart rate by Tanaka, Fox or Gulati formula and five training zones in beats per minute, with Karvonen reserve zones when resting rate is given","url":"https://saylorinnovations.com/api/health/heart-rate-zones?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET"],"type":"string"},"queryParams":{"type":"object","required":["age"],"properties":{"age":{"type":"string","description":"Age in years"},"resting_hr":{"type":"string","description":"optional resting heart rate for Karvonen zones"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string","const":"json"},"example":{"type":"object","required":["age","estimated_max_hr","zones"],"properties":{"age":{"type":"number","description":"Age used"},"note":{"type":"string","description":"Caveat or context for reading the result"},"zones":{"type":"array","items":{"type":"object","properties":{"zone":{"type":["string","null"],"description":"Zone name"},"bpm_low":{"description":"Bpm low"},"percent":{"type":["string","null"],"description":"Percent of maximum heart rate"},"bpm_high":{"description":"Bpm high"}}},"description":"Training zones with percent of max heart rate and the beats-per-minute range"},"method":{"type":"string","description":"Method used"},"source":{"type":"string","description":"Data source the values come from"},"resting_hr":{"type":["number","null"],"description":"Resting hr"},"zone_method":{"type":"string","description":"Zone method"},"estimated_max_hr":{"type":"number","description":"Estimated max hr"},"vo2_max_estimate":{"type":["number","null"],"description":"Vo2 max estimate"},"fat_burn_range_bpm":{"type":"array","description":"Fat burn range bpm"},"heart_rate_reserve":{"type":["number","null"],"description":"Heart rate reserve"},"resting_hr_category":{"type":["string","null"],"description":"Resting hr category"}}}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.01","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.01/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_kGgg5kqucU-0eBrqwApIS","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.01","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Calculates estimated maximum heart rate using Tanaka, Fox, or Gulati formulas and returns five training zones in BPM, with optional Karvonen heart rate reserve zones when resting heart rate is provided","exampleAgentPrompt":"I'm 38 years old with a resting heart rate of 58 bpm — can you calculate my five heart rate training zones using the Tanaka formula and also show me the Karvonen reserve zones?","exampleUseCases":[{"title":"Personalized cardio training plan zones","prompt":"I'm 42 years old and want to know my heart rate training zones for a marathon training program — use the Tanaka formula and show me all five zones in BPM."},{"title":"Fat burn zone for weight loss workout","prompt":"What's my fat-burning heart rate zone? I'm 29 years old, my resting heart rate is 62 bpm, and I want the Karvonen-adjusted zones so the ranges account for my fitness level."},{"title":"Senior fitness heart rate guidance","prompt":"Can you calculate heart rate zones for a 67-year-old woman using the Gulati formula? She has a resting HR of 70 and wants to know safe BPM ranges for her cardio workouts."}],"resultDescription":"Returns a JSON object containing the age used, the estimated maximum heart rate (BPM), the formula method applied, all five training zones with their BPM low/high ranges and percentage of max HR, and when resting HR is supplied: heart rate reserve, Karvonen reserve zones, VO2 max estimate, fat burn range in BPM, and resting HR category.","failureModes":["Missing required 'age' query parameter returns an error","Non-numeric or out-of-range age values may produce unexpected results","Invalid method name not matching Tanaka/Fox/Gulati may fall back to default","Network or payment (x402) errors prevent the response from being returned"],"whenToPreferThis":"Choose this endpoint when you need formula-based heart rate zone calculations grounded in established exercise science (Tanaka, Fox, or Gulati methods) rather than generic estimates. It is ideal when resting heart rate is known and Karvonen reserve zones are required for more personalized training guidance. Prefer this over generic fitness APIs when you need structured multi-zone output with BPM ranges and percentage breakdowns in a single call.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-18T12:56:34.516Z","isFirstParty":false,"canonicalSlug":"saylor-innovations-heart-rate-zones-calculator-3d384dcb"}