Heart rate changes after 6 weeks SSB1

I don’t know much about how heart rate works -

After doing SSB1 for 6 weeks I created the following plot in excel to compare my before and after ramp test results. I was a bit surprised during the 2nd test I blew up 7bpm lower than my previous test but managed to get further into it

I created a scatter plot then and found the 2 HR curves were modeled well by parabolas of the same curvature only a different height offset (of about 10bpm)

Does anyone know, does this means my stroke volume has gone up? My only concern is that I couldn’t reach the same Max HR, and my ‘threshold’ heart rate seems to have actually decreased (180 to 175) while my FTP went up (269 to 278), does anyone know if this is normal?

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Do you happen to have the cadence data from both ramp tests? A lower cadence usually results in a lower heart rate (more muscular contribution), while a higher cadence results in a higher heart rate.

Other factors to consider: (the usual influencers on heart rate and the reason why it’s better to train with power)

  • time of day when you executed the workout (I usually get higher heart rate readings in the morning)
  • fatigue: if you are fatigued, heart rate is usually harder to get up high
  • caffeine intake? more caffeine might bump up your heart rate
  • temperature of the environment

OR you might just got fitter :wink:

Regardless… that’s a nice bump in FTP, good work! Keep it up!

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Ok here’s all the data ! I tried to keep everything the same

  • Cadence 86 & 87 from 1 to 2
  • time of day: 18:01 & 17:08
  • Air con set to same temp and fan at same position
  • caffeine intake good point I forgot about that, but I think on both days I’ve had 2 coffees
  • Fatigue - I found the first 3 weeks of SSB1 quite challenging but after week 4 they became easy and I started building in more Zone 2 work, by week 6 I was thinking I didn’t need the whole week to recover but did so anyway just incase, so I don’t think it was the '‘fatigue drop"’

Just to clarify the only reason I’m concerned is that I know lower resting HR is meant to be better, but wasn’t sure if it was the case for the top end. I know the crude formula HRmax = 220-age would start putting me much older than I am if this trend were to continue (27 in 12 days)

My heart rate is generally 5-10 bpm higher when cycling if I’m fresh. My guess is you came into the first ramp test without much training load, whereas the second one you have a little residual fatigue from the SSB1 plan. I can still perform the same in spite of this though so I wouldn’t worry too much about it. One of the reasons heart rate is a tricky metric to train by on its own!

I think your data are super interesting! I’m not sure I see a clear cause for the difference in heart rate between the two tests but based on your data it for sure looks like there is a difference! Another variable that can impact heart rate is hydration…so maybe if you were better hydrated during your more recent test. Seems like a stretch, though. I think you’d definitely remember if you were dehydrated to that extent.

One thing that often gets repeated in TR circles is that HR can vary wildly from day-to-day for similar power outputs. So you could also put it down to that. I should say, though, that has not been my experience. My heart rate is pretty rock solid at given physiologic states & there is not much day-to-day variation…but maybe I’m an outlier in this respect.

Very interesting data, though!

I’m the same with regards to heartrate - it is pretty stable relative to the effort, and if factors like temperarure or tiredness influence it, that is usually pretty obvious to me early on. Also people trained for years just based on heart rate, so it can’t be totally useless imo. Power might be a better metric to use, but HR isn’t as useless to me as some people say.

@Rowan899, did you see the same HR trend in other workouts, apart from the two ramp tests? Eg did you reach your previous max HR less often during workouts?