Triathlon12 min read
Which Triathlon Distance Should You Choose?
Sprint, Olympic, 70.3 or Ironman? Compare all 5 official triathlon distances side-by-side and pick the right one for your fitness, time and goals.
Read articleLatest Articles
Tips, guides, and news to optimize your training.
Health12 min read
VO2 Max and Longevity: The Best Predictor of Lifespan
A landmark study of 122,007 patients found that elite fitness reduces all-cause mortality by 80%. Learn how VO2 max predicts lifespan and how to improve yours.
Read article
Guide14 min
RPE Scale: The Complete Guide to Rating Perceived Exertion
Learn the RPE scale (Borg 6-20 and modified 1-10) to regulate training intensity. Interactive chart with HR zones and running guide.
Read articleTraining Zones Explained
From active recovery to all-out sprints - each zone triggers different adaptations to optimize your performance.
Metric
1Recovery
2Endurance
3Tempo
4Threshold
5VO₂max
Heart Rate
50–60%
60–70%
70–80%
80–90%
90–100%
Perceived Exertion (RPE)
1–2
3–4
5–6
7–8
9–10
Breathing
Easy conversation
Can hold conversation
Short sentences only
A few words only
Unable to speak
Running
Very easy jog
Easy, steady pace
Sustained pace, half-marathon
10K pace, hard effort
Sprint, all-out effort
Cycling (% FTP)
< 55%
56–75%
76–90%
91–105%
> 105%
Swimming (% CSS)
< 75%
75–85%
86–95%
96–105%
> 105%
Energy System
Fat oxidation
Fat + some carbs
Carbs + fat
Mostly carbohydrates
Anaerobic (ATP-CP + glycolysis)
Sustainable Duration
Trained: > 7 hBeginner: < 3 h
Trained: > 5 hBeginner: < 2 h
Trained: 2–3 hBeginner: < 45 min
Trained: 20–60 minBeginner: < 20 min
Trained: 5–7 minBeginner: < 3 min
Key Benefit
Active recovery, blood circulation
Aerobic base, fundamental endurance
Lactate threshold, running economy
VO₂max, maximal aerobic power
Maximum speed, anaerobic power
HR= % HRmaxFTP= Functional Threshold PowerCSS= Critical Swim SpeedRPE= Rate of Perceived Exertion (1–10)
← Swipe to see all zones →