Ask a coach: 'Should I be paying attention to 'Pulse Ox' readings on my Garmin smartwatch?'

So you've bought a fancy smartwatch with data metrics you've never come across before - Pulse Ox being one of them. We take you through what this metric is and how useful its numbers really are

Female cyclist wearing a smartwatch while riding on a country lane in Wales
(Image credit: Future)

Garmin (and other smartwatch manufacturers) have relatively recently started allowing users to measure their ‘Pulse Ox’. Pulse Ox is a proxy for what sports scientists call SpO₂. Essentially this is the oxygen saturation within the blood; the percentage of haemoglobin carrying oxygen.

Traditionally SpO₂ has been measured using a device placed on the fingertip. The device shines a light into the fingertip and by measuring the amount of refracted and absorbed light it can calculate the percentage of haemoglobin carrying oxygen. Measuring SpO₂ is a standard procedure in medicine. But can tracking SpO₂ help cyclists and is the technology that the best smartwatches for cycling use accurate enough to make this data worthwhile monitoring? Cycling coach James Spragg unpacks the topic...

Image shows James Spragg.
James Spragg

Sports scientist and coach James Spragg is one of the experts who will be answering your questions in Cycling Weekly's ASK A CYCLING COACH series which comes out every Wednesday. Working both in research and applied settings, he currently runs Intercept Performance Consultancy

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James Spragg

James Spragg is a sports scientist and coach, working both in research and applied settings. When not working with athletes James can be found skiing, climbing, cycling or drinking coffee!

Alongside Dan Lorang and Peter Leo, James runs Intercept Performance Consultancy. Over the last 8 years in various roles, as coaches, performance consultants, performance managers, and sports scientists, Dan, James and Peter have played a role in helping athletes achieve more than 10 World Championship titles, several Olympics medals (including a Gold and Silver Medal in Tokyo 2020) and several Top 5 results in some of the biggest sporting events on the planet (Tour de France, Olympics, World and European Championships). Our single focus is on improving performance in all settings.