Terra
Integrations
Research

Integration

API
Unified API
SDK
SDK
Authentication
Authentication
Streaming
Streaming
Blood
Blood Report API
Planned Workouts
Planned Workouts
AI Interface
AI Interface

User engagement

Graph API
Graph API
Scores
Health Scores
Rewards
Health Rewards

Use cases

Enterprise
Enterprise
Insurance
Insurance

Developers

Wearable Data
Wearable Data
Community
Community
Documentation
Documentation

Learn

Blog
Blog
Podcast
Podcast
Events
Events
Reports
Reports

Company

Customers
Customers
Careers
Careers
Partners
Partners
Support
Support
Pricing
Become an integrationGet started
IntegrationsResearch
Unified APIUnified APISDKSDKAuthenticationAuthenticationStreamingStreamingGraph APIGraph APIScoresScoresRewardsRewardsBlood Report APIBloodAI InterfaceAI Interface
EnterpriseEnterpriseInsuranceInsuranceWearable DataWearable DataCommunityCommunityDocumentationDocumentationBlogBlogPodcastPodcastEventsEventsReportsReportsCustomersCustomersCareersCareersPartnersPartnersSupportSupport
Pricing
Get startedBecome an integration
next ventures
pioneer fund
samsung next
y combinator
general catalyst

The world's best health apps run on Terra data

Get started
ProductsIntegrations AI Interface Authentication Mobile Development Documentation GraphAPI
DocumentationAPI SDK Quickstart
CommunityBlog Research Community Podcast Github
CompanyAboutCareersCustomersBecome an IntegrationCookies PolicyGDPRPrivacy PolicyTerms of Purchase
© Terra API. 2026 — All rights reserved.

Cookie Preferences

Essential CookiesAlways On
Advertisement Cookies
Analytics Cookies

Crunch Time: Embrace the Cookie Monster Within!

We use cookies to enhance your browsing experience and analyse our traffic. By clicking “Accept All”, you consent to our use of cookies according to our Cookie Policy. You can change your mind any time by visiting out cookie policy.

Cookies Policy
< Blogs
Terra API
Terra API

April 11, 2022

HR Zone training: What is it, and how can our wearables help us with it?

What is heart-rate zone training?

When it comes to training, heart-rate feedback is an excellent way to monitor workout intensity and to put together training plans that help you improve fitness. Most wearables that track heart rate also allow you to train using heart rate zones that are preprogrammed, or that you set up for yourself. Before we dive into this style of training, its important to understand what the three different heart states are:

  1. Resting heart rate - relatively self-explanatory, this is the rate your heart beats at while you're doing no activity whatsoever. A variety of factors determine your resting heart rate including age, gender, fitness level, and even medications. As your fitness improves, you'll find your resting heart rate fall
  2. Recovery heart rate - the amount of time it takes for your heart rate to return to its resting heart rate after vigorous exercise. Like resting heart rate, it improves with fitness
  3. Heart rate max (HR max) - the fastest at which your heart is able to beat. This is the key spec for setting up your training program. Whilst traditionally this is calculated by subtracting your age from 220 (e.g. at 30 years of age my HR Max would be 190) a more accurate measure can be taken by running a stress test in a lab

What are the HR training zones?

The key principle behind HR training is that different heart rate levels engage different aspects of your physiology, and a good training plan will work in multiple zones to improve overall performance. Heart rate zones also determine what energy source you're using - carbs or fat. The higher your heart rate gets, the more your body starts to rely on glycogen from carbs for fuel.

Whilst the American Heart Association defines two zones for heart rate training (moderate intensity 50%-70% of HR max and vigorous intensity intensity 70%-85% of HR max), it can be broken down into five categories:

  1. Zone 1 (recovery / easy) 55%-65% HR max. Warmup / warmdown zone, easy training
  2. Zone 2 (aerobic / base) 65%-75% HR max. Longer training sessions, sustainable for many miles
  3. Zone 3 (tempo) 80%-85% HR max. Pushing the pace to build up speed and strength
  4. Zone 4 (lactate threshold) 85%-88% HR max. Lactic acid builds up too quickly to be processed and fatigues muscles
  5. Zone 5 (anaerobic) 90% HR max and above. Max speed zone. Body is exerting at full effort.

Typical training plans will utilise multiple training zones, and you won't train in each zone for an equal amount of time, especially depending on your goals. A distance runner may spend more time training in the lower HR zones than say, a sprinter. Somebody looking to build their endurance would want to train in lower zones so that they can sustain it for longer periods.

Elite athletes often pay close attention to their heart rate whilst training. For example, during a one hour time trial Lance Armstrong would often spend almost the entire test with his heart rate at around 200 bpm in order to push his body to the absolute max.

How can our smartwatches help us with this?

Smartwatches are designed to track and record our heart rate whilst exercising and some even give us useful information on how much time we spend in each heart rate zone. By optimising our training and exercising according to heart rate zones we can maximise performance.

Through the Terra API, we provide connections to a range of different devices so that your users can track their steps.

Below is a list of the wearables that track your heart rate today:

  • Garmin Fenix series, Venu series, Lily, Approach, Vivoactive, Forerunner series, Instinct series, Enduro, Descent series, Mk2 series, Epix, Tactix series, D2 series, Vivomove series, Approach series, Vivofit, Marq series, Quatix series
  • Fitbit Versa series, Charge series, Inspire 2, Sense, Luxe, Ace 3,
  • Apple Watch all series
  • Polar Grit X Pro, Grit X, Ignite series, M430, Unite, Vantage series,
  • Withings ScanWatch series, Steel HR, Move ECG
  • Oura ring Gen 3, Gen 2
  • Samsung Galaxy Watch all series, Galaxy Fit2
  • Suunto 9 range, 7 range, 5 range, 5 peak, 3 range, Ambit3, Core range, Traverse
  • Wahoo Elemnt Rival Multisport GPS watch
  • Xiaomi Mi Watch

Related Articles

A new chapter of period prediction

July 26, 2023

A new chapter of period prediction

A new chapter of period prediction Temperature changes and menstrual cycle tracking As a brief introduction, the menstrual cycle is separated into the follicular phase pr

Luba DziojevaLuba Dziojeva
Comprehensive list of wireless sensors in wearable devices (BLE, BT, ANT+)

January 10, 2023

Comprehensive list of wireless sensors in wearable devices (BLE, BT, ANT+)

Comprehensive list of wireless sensors in wearable devices (BLE, BT, ANT+) Many of our clients have asked for a detailed breakdown of what different wearables providers u

Halvard RamstadHalvard Ramstad
Wireless Communication Technologies Breakdown by Wearable Devices (BLE, BT, ANT+)

January 9, 2023

Wireless Communication Technologies Breakdown by Wearable Devices (BLE, BT, ANT+)

Wireless Communication Technologies Breakdown by Wearable Devices (BLE, BT, ANT+) Many of our clients have asked for a detailed breakdown of what different wearables prov

Halvard RamstadHalvard Ramstad

More Topics

All Blogs
Team Spotlight
Startup Spotlight
How To
Blog
Podcast
Product Updates
Wearables
See All >
The complete guide: How the new Google Health API works

The complete guide: How the new Google Health API works

Google Health API replaces the Fitbit Web API. This is the field guide with code, schemas, and a migration playbook to help you understand where Google Health is heading.

Vanessa NeeffVanessa Neeff
May 18, 2026
September 2025 updates

September 2025 updates

July: Terra Research launches, Lab Reports land in the dashboard with PDF/Image → JSON, and Samsung Health moves to the new Data SDK for a tighter Android integration. 🚀

Alex VenetidisAlex Venetidis
October 1, 2025
August 2025 updates

August 2025 updates

🎉 July Highlights: InBody Goes Global, Faster APIs, and Rock-Solid Data 💪📊

Alex VenetidisAlex Venetidis
September 1, 2025
July 2025 updates

July 2025 updates

July = rock-solid Terra: WHOOP V2, Garmin & Fitbit bug fixes, faster SDKs, plus bulk blood-report uploads with smarter reference ranges. Reliability + data power-ups! 💪🩸

Alex VenetidisAlex Venetidis
August 2, 2025
June 2025 Updates

June 2025 Updates

June brings Terra MCPs for AI-driven setup, Fern-powered Python/JS SDKs with strong typing, and official Expo plugin support—build faster with less friction. 🚀🧰📱

Alex VenetidisAlex Venetidis
July 1, 2025