Variations in heart rate from day to day

jswigart

I realize there is probably not an easy answer to this but here goes.
I wear a polar heart monitor strap around chest when exercising. It links to my smart phone.
I find some days it is much easier to raise my heart rate than others.
I cannot figure out what the variable is? It doesn't seem to matter what I've eaten or drank.
For Example:
While riding my bike one day I will achieve 155-160bpm and other days I have to work really hard to achieve 145-150.
Any ideas? J

Charabz69

Hi

Are you on the same terrain both times? Hill climbs etc will cause your HR to raise as much and some times more than a sprint?

jswigart

Yes, identical path each time.

stealthq

Lots of things affect heart rate. I think the three most common (given identical workouts otherwise) would probably be:

1) accumulated fatigue
2) temperature (but I'm guessing you'd have thought of this)
3) common stimulants and depressants (caffeine, nicotine, alcohol) can affect HR long after being taken

But, my bet would be accumulated fatigue.

ETA: thought of one more common one - hydration

NorthCascades

Sometimes, when I'm on my way to a hike in the middle of nowhere, I wind up stuck behind that one guy in a Jeep who needs to do 40 mph on a one-lane highway. On the other hand, I live in a big city, and when I come home from work, it's rush hour and the freeways are like a parking lot, but it's not just one guy going too slow, it's everybody.

I think your HR response is going to be more like rush hour traffic - not just one variable controls this. More likely it's a combination of things like @stealhq mentioned (training load probably varies from day to day, temp, hydration, plus differences in actual exertion, etc).

jswigart wrote: »

Yes, identical path each time.

None of us ride with you so we're grasping at straws here. Stop lights and wind and traffic all make it so that average speed doesn't really work for cyclists as a way to gauge fitness even on the same route.

TimothyFish

I find that the biggest contributor is air temperature. The hotter it is the more your body has to do to keep you cool, and that includes pumping a lot of blood.

jswigart

Thanks folks. A lot of good info to consider.

sarabushby

Also consider:
- stress (increases HR)
- Lack of sleep (increases HR)
- Nutrition (have you refuelled properly since the last workout and fuelled properly for this one?)
- Mood ( if it'you're happy your HR may be lower eg if it's the weekend and the sun is shining vs after a stressful day at work and the weather is grim)
- Illness (if you're fighting a bug your HR may be higher than usual)
- Hydration has already been mentioned but is SO important

And as already mentioned, you then have the things which affect your RPE (rate of perceived exertion), so what can make you feel like it's harder or easier. Some of the above apply both ways but for sure caffeine is proven to reduce RPE.

jswigart

I think that the "rate of perceived exertion" is probably the main culprit. :-)