HR during Moderate Intensity Exercise is almost Max HR

[xABx]

Looking for any suggestions or guidance here regarding something I've noticed recently that has me concerned.

After a couple of years of sedentary lifestyle my weight had crept up to 250lbs and I had become lazy. I wanted to get in better shape and be more active, so I bought a Fitbit in March and since then have been walking 5 miles a day, counting calories and got my weight down to 217lbs.

My RHR at the outset was ~67bpm but this is now down to 59bpm which I'm aware is considered Bradycardia since I aren't a highly conditioned athlete. This made me take more notice of my HR in general. I have noticed that during moderate intensity exercise (i.e. during a brisk 2.5 mile walk) my HR randomly spikes to almost my Max HR despite me not doing high intensity activities.

I'm 32 years old, so my Max HR is 188. Today my HR hit 183bpm just during a brisk walk. Looking back I can see this has happened on other days recently (177bpm - 185bpm). I have also noticed that randomly during the night my HR spikes to around 85bpm suggesting perhaps undiagnosed sleep apnea?

Is this something to be concerned about? I fear I'm becoming a hypochondriac in my middle age.

[JohnnyRow]

Congratulations on getting more fit; keep it up.

I'm no medical expert so best to ask your doctor.  But you say your heart rate spikes to near max during moderate intensity walks.  Does it stay there, or is just brief spikes when look back at heart rate chart?  If it is just brief spikes, I would guess that is just a temporary blip from Fitbit rather than something to be concerned about.

[xABx]

Thanks for the words of encouragement! I am trying to be a better, healthier version of myself.

I have my Fitbit linked with the Cardiogram App, and this is a typical example of how my HR increases on my walk to work. There is no notable incline along the route to explain it, nor do I feel overly exerted at the time, just increased breathing as you'd expect on a moderate intensity walk.

It makes me curious as to how high it would spike if I actually jogged/ran.

[Heybales · Accepted solution]

59 is considered Bradycardia? Where is that high a level said to be a concern?

Approaching 50 isn't even required to be a "highly conditioned athlete", really just doing good aerobic workouts can accomplish that.

Approaching 40 needs some special training though.

Have you ever confirm those spike times with manual reading at the neck - just 6 sec to confirm really that high.

You may find it's a mistake.

Same as when you get to point of doing higher HR workouts - the HR loses accuracy over a certain point or drops out from time to time - some find that happens.

Also be aware that unless you find a way to increase the intensity of your workouts with like hills - moving 33 lbs less around with walking that usually has a max speed to it - means it's not as much a workout. So improvements have been slowing down.

At some point if you don't increase the intensity and weigh less - you can lose fitness.

Need to know too that your HRmax is estimated to be 188 per a simple and old formula, that has a decent bell curve to it. Not as wide as the women's is - but still could easily be off 20-30 bpm.

Here's some alternatives (even among all these, this is 20 bpm lower than reality for me):

https://www.brianmac.co.uk/maxhr.htm

And using the restingHR to get better training zones, you can tweak this on Fitbit if looking to do certain types of workouts - may not matter yet though.

http://www.calculatenow.biz/sport/heart.php?

And to test on a walk sometime, and you are Excellent in this description with daily walks that are not for site-seeing pace, right? Submaximal not always dead on either, but there are several versions.

https://doctorholmes.wordpress.com/2008/11/17/determine-your-mhr-with-a-1-mile-walking-test/

I wonder if your sleep elevated is just flakiness of device - might test during the day moving it in manner on wrist that might happen at night to see if you get spikes.

Or rough dreams - I and others have awoken with heart racing from a dream.

Good job with your workouts. If you feel the need to visit a Dr, or at least get a consult. But I'd confirm accuracy first.