Can a sunburn increase your resting heart rate?
I've been using a Fitbit to track my resting heartrate (among other things). The value has consistently been in the 55-60 range for several weeks (most typical value over the past week or two is 57). Over the past few days, however, it jumped to around 62; a 10% increase.
The bulk of the increase occurred 2 days ago, and the only thing I can think of that happened within that timeframe is that I got a mild sunburn (from kiteboarding, so primarily on my face/forehead from looking up at the sky all afternoon). But correlation doesn't necessarily mean causation. So my question is, can a sunburn lead to an increase in the body's resting heartrate? And if so, why?
Misc Notes
I know a Fitbit isn't a medically accurate device, and that there's pending litigation over whether they're accurate at all. However my anecdotal experience with my particular device is that it's quite accurate when at rest (during strenuous exercise the instantaneous readings can indeed be a bit funky and it can temporarily lose count altogether; although the average values that get logged to the dashboard seem reasonable despite the transient outliers/glitches). So I don't think device inaccuracy/margin of error is the explanation.
(1)1 Comments
Sorted by latest first Latest Oldest Best
One word: dehydration.
You spent a day out in the sun, exerting yourself, and probably didn't maintain your normal level of hydration. Consequently, you're mildly dehydrated (or, more properly, hypohydrated).
Dehydration means a lower blood volume, which in turn means your heart has to beat faster to move the same volume of blood. Consequently, your heart rate is mildly elevated until you restore your normal hydration levels.
Summary of Findings 1
Scientific Definitions: Hypohydration is the steady state condition of decreased total body water. Dehydration is the process of losing body water (eg, during exercise).
Body mass losses as small as 2% have been shown to result
in an increase in cardiovascular strain and subsequently
decrease performance during exercise. Exercise in the heat
further exacerbates cardiovascular strain, thus causing further
decrements in performance.
Results have shown that for every 1% decrease in body mass
during exercise in the heat there is an increase in heart
rate of 3.29 beats/min. This equates to an increase in heart
rate of 10 beats/min if an athlete is 3% dehydrated.
Exercise at a fixed and variable intensity has shown an
increase in heart rate of 3.55 and 1.39 beats/min respectively
during exercise in the heat.
Terms of Use Privacy policy Contact About Cancellation policy © freshhoot.com2025 All Rights reserved.