Wearables: Helping or Hurting? (Fast Talk Podcast Ep #266)

Man, oh man, did I enjoy the podcast episode on wearable devices. Sure, it was confirmation bias at its finest, but it was so nice to hear a roundtable of experts expressing views I’ve held myself for some time.

Thanks @Mudge! Really glad you enjoyed the episode! It’ll be interesting to hear from the members who don’t agree. I hope we get a good conversation going here!

I only listened today, and also enjoyed it. I’m definitely on the side of simplicity, with the basic metrics being used to measure performance. My metrics are:

  • HR and Power
  • RPE and Feel
  • Daily HRV & RestingHR (for the trends)
  • Daily Mass
  • Morning feel (tired or refreshed)
  • Daily mood

There was a comment on a local MTB WhatsApp group where someone was asking about a smart watch that can measure blood pressure. It took a lot for me to keep quiet, among all the comments from the “couch experts” on the group. The cost of a standalone device is much cheaper than the smart watches quoted.

Wrist-based HR
I’ve dual recorded using my Garmin 735XT (wrist based HR only), and Lezyne head unit (Polar H10 HRM) to compare the beat per beat on different activities/terrains. The difference is 1bpm (average) across all durations tested, but there is a lag at changes in intensity. The values are acceptable for me should my HRM strap be unavailable, but I hardly train/ride/race without wearing the HRM strap.

I use my Polar H10 together with HRV4Training as well as Kubios, and take a reading every morning in the same position, and as soon as I have woken up (the time varies throughout the year).

The trend is important rather than the daily values, along with RHR.

Core Body Temp sensor
I was contemplating getting one, but @robpickels has convinced me otherwise.

I’ve used the Scosche Rhythm+ optical HRM for a long time because one of my two competitive sports is inline speed skating, where your hands are behind your back for long periods. In that position the chest HRM data is spotty (lots of data points dropped). My testing showed it produces the same quality of data as a chest HRM but without the drops while skating, since it is on my forearm. However, rowing it is more or less useless. On the bike, both of them work equally well. The wrist HRM of both the Garmin 935 and Epix were/are more or less useless for me once I warm up. They’re off by 20+ bpm.

I don’t have any wearables, just gps with hr and power when on bike. Plus I do the HRV4Training in the morning. That’s it.

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Hi everyone, this is my very first time on this forum, but I felt really strongly about this, so I had to say something.

I disagreed with the discussion regarding the Core Body Temperature monitor.

I 100% believe that this is a metric that you can and should take action on during a race.

A few years ago I was a participant in a XC Marathon race where a competitor died because his core body temperature was too high and his organs literally cooked. At the same race another of my friends passed out and fell off her bike within 2km of the finish because of the heat and ended up in hospital overnight.

Many others made the smart decision to pull out during the race as they felt too hot, and I jumped in the swimming pool completely clothed after the race to try and cool my body down.

I understand that this is an extreme situation that should never have happened for many, many reasons, but a core body temperature sensor would allow a competitor to take action sooner with cooling strategies to bring the body temperature back down.

Going further with this, we can learn through our training at what temperature our power levels drop significantly, so then during an event, if we reach that temperature we can apply cooling strategies like pouring water on our heads to bring the temperature back down and our performance level back up.

We can also learn if our heat acclimation strategies are working and the tipping point of body temperature to power decline is increasing, allowing us to perform better in hotter conditions.

So I think that a core body temperature sensor would be a very useful tool both during competition and training, and it is something that you can action during the race.

Stephanie, I appreciate your sharing and offer my sympathies for these unfortunately situations.

My issue with the Core body temp sensor is that it might not protect athletes.

  1. This is an indirect measurement of core body temp - looking at the surface skin temperature and the environmental temperature and through an algorithm trying to predict the athlete’s core temperature.

There are numerous example of this being potentially inaccurate. For example, wear a vest over the sensor and the sensor will miscalculate due to the microclimate in that area not being representative of the whole-body condition.

  1. Even if we assume that the device is accurate to 0.1c, we do not have good recommendations that apply to all athletes about what is safe. There is no universal cut-off and we cannot determine per athlete without putting them in harms-way.

For example, we can do an FTP test to failure and get a generally good understanding of their capabilities. They will be extremely tired, but they will be safe. We cannot exercise someone to heat-exhaustion to see what their maximal temperature is - and in fact they will likely quit prior to reaching this point as the alarms in the head go off.

  1. Athletes, when given a number, will do anything they can to achieve that number - they will disregard what the alarm bells are telling them. If we say it is perfectly safe for to 40c of core temperature and they’re extremely hot - have all the signals telling them to stop but there temp only reads 39.5c, well they are going to keep pushing and disregard!

Because of the above points, my opinion is that it’s imperative that athletes listen to their bodies. This is a far safer recommendation that hopefully keeps athletes out of harm’s way.