𝗬𝗼𝘂𝗿 𝗪𝗮𝘁𝗰𝗵 𝗠𝗶𝗴𝗵𝘁 𝗕𝗲 𝗟𝘆𝗶𝗻𝗴 𝗧𝗼 𝗬𝗼𝘂

@everyone “𝗬𝗼𝘂𝗿 𝗪𝗮𝘁𝗰𝗵 𝗠𝗶𝗴𝗵𝘁 𝗕𝗲 𝗟𝘆𝗶𝗻𝗴 𝗧𝗼 𝗬𝗼𝘂"
Wrist-Based Heart Rate Monitors Could Be Costing Your Results

If you are new to triathlon or endurance sports this is pretty important to know now, so come to race day you have the right data to work with.

This is especially important in two main scenarios

1. If you’re using a smart trainer with a power meter indoors and then switching to heart rate as your main metric for measuring cycling intensity outdoors.
2. If you are using Heart Rate to measure run intensity. This is especially useful when “Pace” metrics aren’t as relevant, for example off off-road running. I’ve seen big swings in heart rate which are not related to the intensity an individual is putting in when individuals are using wrist-based heart rate monitors

𝗔𝗰𝗰𝘂𝗿𝗮𝗰𝘆 𝗺𝗮𝘁𝘁𝗲𝗿𝘀 𝗯𝘂𝘁 𝗵𝗲𝗿𝗲’𝘀 𝘁𝗵𝗲 𝗶𝘀𝘀𝘂𝗲:

1. Wrist-based heart rate monitors often fall short during intense or bumpy activity.
2. They rely on light sensors to estimate heart rate, not direct signals from the heart.
3. Studies show their readings can be off by 5–10 beats per minute, especially during running.
4. The errors aren’t consistent. One day it might be slightly low, another day wildly high.

𝗪𝗵𝘆 𝘁𝗵𝗶𝘀 𝗺𝗮𝘁𝘁𝗲𝗿𝘀:

1. If your aerobic threshold is 150 bpm, a 5% error could mean training at 157 bpm.
2. That small shift could reduce recovery, affect adaptations, or hurt race performance.
3. You won’t know if your workout hit the right zone, or just felt hard.

𝗪𝗵𝗮𝘁 𝘁𝗼 𝗱𝗼 𝗶𝗻𝘀𝘁𝗲𝗮𝗱:

1. Use a chest strap or armband for outdoor sessions. It’s closer to 100% accurate.
2. Compare your devices: try 6 x 1-minute hard intervals with your watch and a chest strap. Do they match?
3. If your heart rate data looks random or off, trust the chest strap — not your wrist.

𝗕𝗲𝗳𝗼𝗿𝗲 𝘆𝗼𝘂𝗿 𝗻𝗲𝘅𝘁 𝗯𝗶𝗴 𝘁𝗿𝗮𝗶𝗻𝗶𝗻𝗴 𝗯𝗹𝗼𝗰𝗸 𝗼𝗿 𝗲𝘃𝗲𝗻𝘁 𝗽𝗿𝗲𝗽, 𝘁𝗮𝗹𝗸 𝘄𝗶𝘁𝗵 𝘆𝗼𝘂𝗿 𝗰𝗼𝗮𝗰𝗵.

𝗔𝘀𝗸:

* What heart rate data do you need to guide my training?
* Are my current tools giving us accurate info?
* What can I improve to hit my race goals?

A few beats off might not seem like much, until it is.