Exercise/diet and RHR going down

[PaulBunyanPacNW]

Hello Folks!

i was reaching out to see if anyone has any anecdotal experiences with weight loss + exercise driving RHR down?  I started using my FitBit in Oct ‘19 and have lost almost 50 pounds since.  Been doing calorie tracking and elliptical (7 days a week @ 35 mins and reaching cardio zone for the majority of the workout session).

RHR started at high 50s and now sits at 48-46 BPM.  Everything I’ve read seems to indicate my RHR is “conditioned athlete” level (I’m not).  Even had the Dr run a couple tests (thyroid, EKG, etc) and no issues identified.  

Anyone else have experiences with RHR taking a large downward trend after consistently wearing a FitBit and adopting a healthier lifestyle?

Thanks all!

[Heybales]

High 50's to mid/high 40's is not that much of a drop really, not for what you've done.

High 50's was showing you likely already had some conditioning - avgHR for truly sedentary is higher than that, and when those folks start getting fit, the drop is even greater.

The potential lower end is genetic, outside health or medicine reasons - which sounds like you got checked out already.

Those just aren't values to be concerned about - and 7 x weekly of cardio is conditioned athlete in the scheme of that description.

Has your HR zones moved up in numbers since the start?

Because if you have always kept your workout to the same level of HR, and those ranges haven't changed since you got more fit and lost weight - you are holding yourself back in a sense.

Think of it in lifting terms.

You squat XXX lbs, 3 sets of 12 reps 3 x weekly.

That is difficult for you at this one point in time at the start.

But then 3 months go by, and you are still doing the exact same routine. Except you actually weigh 50 lbs less, so really you are squating XXX-50 lbs.

Is your workload even the same? No, it's less.

If it actually feels difficult still - you would have lost muscle mass.

So also the cardio, if the workload hasn't gone up (and maybe it has to reach the same HR, but that would be merely from moving less weight around), then your fitness level would actually not be doing any harder work it could do.

So just a side point, because unless you are hitting your genetic restingHR barrier, I'd frankly expect it to be lower from that much cardio.

But if the HR zones aren't increasing, then that would explain the smaller improvement.

[PaulBunyanPacNW]

Thanks for the detailed response!  I think you bring up a good point that I probably have an opportunity to push my max more than I do.  I vary incline/resistance every week, but perhaps I should push outside my “comfortable” zone.  My sessions usually hover in the 139-143 BPM zones - so around 80% max.

[Heybales]

Is that HRmax a tested value, or the huge bell curve of 220-age?

Accuracy of HR zones could be very lacking.

True, you may have a diesel heart and it's lower, you could also have a race car heart and it's higher.

Usually Lactate Threshold level (Anaerobic Threshold) is considered to be about 80-85% of HRmax, which means if you can hold that line for 20-30 min, but not really much more intensity, then that HR zone is top of aerobic level. Perhaps the HRmax is correct then.

Of course with that much time spent in aerobic zone, muscles may be able to handle a higher session now - your LT/AT level may have risen from the exercise even if HRmax is correct.

Either way, like the lifting analogy, if the intensity hasn't gone up much and still hitting the same HR after losing 50 lbs - you can probably do more than you think.

Make sure you change the description on that first workout so you can find it again in your Exercise diary - will be interesting to compare down the road.

Next thing you know - you'll be doing interval sessions, then testing that HRmax!