This will be an interesting week with running. It’s gonna be hot and humid and I’m sure my heart rate will skyrocket! Or will it? Does it even matter?
Maybe it doesn’t; some of my research said it really doesn’t. I just like to understand things. I have a curious mind. Definitely still no expert, but I found a few interesting things.
Heat increases HR
Hardly shocking, right? According to this post here:
You can plan to add 2-4 beats per minute when the temperatures rise from 60-75* and another 10 beats per minute when temperatures soar from 75-90
This does not explain my recent HR variations.
Another nugget from the same post:
As you become dehydrated, blood volume decreases and less blood is pumped with each stroke.
A fluid loss of as little as 1% can cause your heart rate to raise 7 beats per minute.
I am a thirsty runner. I hydrate before my run, I’ll do Nuun the day before hot runs — I used to do Nuun before on the day of hot runs — this may be another thing for me to explore.
I actually am aware of this one, I mentioned it recently. From this post here:
However, exercise research has shown that it is common to see heart rate “drift” upward during an easy or threshold run, even with no increase in pace of effort – sometimes by as much as 10-20 beats per minute over a 30 minute period.
Hmmm. Now we’re getting closer, maybe. That post goes on to say within 30 minutes your HR might increase 20 beats, but if you slow down you won’t get the best bang for your exercise buck — if you catch my drift (pun intended).
What’s a hot runner to do?
I also found this post here:
Studies have shown that when the temperature rises above 65 degrees, your heartrate will also rise by about 10 beats per minute and performances will slow. If the humidity is also high, add another 10 or so beats to that number. My own experience tells me that under these types of conditions, my average pace will often be off by 10 to 20 seconds per mile at the same effort level. What does this mean? In short, slow down.
He actually goes on to write:
If your average heartrate on a typical tempo run performed under near-ideal conditions is in the range of 165 to 170 beats per minute, on a hot, humid day, trying to maintain that type of effort will yield a number in the neighborhood of 190. While you do everything in your power to stay “on pace,” you’ll also be working dangerously close to your max heartrate and exerting yourself at an effort level that’s much greater than it should be for that given workout–or is even safe, for that matter.
The interesting thing (to me, anyway) was that I gave myself some leeway and assumed my HR would be higher than normal. I ended my last run feeling just fine, too (and with a decent pace for the last mile when I just sorta let er rip)>
Other reasons your heart rate might be higher than normal
Heat and humidity aren’t the only things that drive your heart rate up. Other things that may effect it:
- Lack of sleep
- Thyroid problems
There’s even a few more reason in this post here.
I’m not worried, but I am still curious! I don’t feel the need to see a doctor. I also looked back at some of my runs from July and August last year. There were several where I also had a high heart rate, but for the most part they were pretty normal for me. I haven’t really come to any conclusions yet!
The interesting thing is it’s been one year since my mom broke her hip — so there absolutely was lots of stress in my life last Summer! I am running more monthly miles this year — simply by running longer long runs. Definitely not racking up a lot of miles, though.
What makes you go hmmm about running?
Do you want to know why it happens?
This week I am also joining up with the new Runners’ Roundup linkup.