Vaughn Follow

17 October 2026

Chest strap vs wrist, same workout.

I wore a Polar H10 on my chest and a Fitbit Air on my wrist through the same 55 minute strength session. Both can work. It depends on how accurate you want your training to be.

Two lines over 55 minutes. The chest strap tracks fast changes closely; the wrist reading diverges most when heart rate is moving, with a 37 beat overread at minute 46 and a 19 beat underread at minute 29. Every minute is listed in the table below the verdict.

Move across the chart to read any minute.

At first glance, it looks pretty good.

The session average was 129 on the chest and 131 on the wrist. Training load came out within 5%, and both put me in zone 4 or 5 for the same 14 minutes. If you only care how hard today was, the wrist gets you there.

Look closer, and it's a different story.

42%of minutes, 23 of 55, the two put me in a different heart rate zone.

Minute by minute they were 7.6 beats apart on average, and the gap grew when my heart rate moved: 5.8 beats on steady minutes, 10.4 during working sets. At minute 29 the wrist read 19 beats under a hard effort. At minute 46 it read 37 beats over a rest. The errors ran both ways, which is why the average still looked right.

The workout

Sets as reps, or reps × pounds. hardto failure

Explosive / Power

Box Jump

  • 5
  • 5

SL Depth Jump w/ Stabilization

  • 5
  • 5

Strength

Back Squat (Full ROM)

  • 10 × 135
  • 10 × 155
  • 10 × 175

Bulgarian Split Squat

  • 8 × 70
  • 10 × 70 (hard)
  • 10 × 70 (hard)

Single Leg Lying Leg Curl

  • 10 × 50
  • 7 × 50 (to failure)
  • 3 × 50 (to failure)

Chest vs wrist, side by side

The same load formula, zones and max my app uses, run on both.

MeasureChestWristDifference
Session load (TRIMP)66.269.7+5.3%
Minutes in zone 4 or 51414none
Peak heart rate170166−4 bpm
Session average129131+2 bpm
Minutes in a different zone23 of 55 minutes42%

So which one? Both.

If you want your training as accurate as it can be, wear a chest strap like the Polar H10 for workouts, practices and games, where every minute counts. Let your wearable capture the rest: your sleep, your recovery overnight and the hours in between.

Be first to know when Vaughn launches.

Vaughn reads your chest strap beat by beat, alongside your training, sport and recovery. Leave your email and we'll tell you the day it's on the App Store.

Updates from Vaughn. Unsubscribe any time. Privacy