Tuesday tip: Why am I burning fewer calories? 🏃🏼♀️
If you wear an activity monitor / heart rate monitor / smart watch you may have noticed that over time you burn fewer calories when exercising.
These monitors measure calories burned based on your heart rate during exercise.
There are wrist and chest strap versions. The chest strap ones measure electrical impulses from heart (like an EKG). The wrist based ones use an optical sensor to measure heart rate based on blood flow. When your heart rate increases blood flow increases so the sensor uses this change to estimate heart rate. Due to this any exercise that impacts blood flow to the wrist will reduce the accuracy of the heart rate measure e.g raising arms above the head, burpees, planks etc. So there are already inaccuracies in the measure anyway.
Regardless of which method you use over time you will find you burn fewer calories than you used to. The body is designed to adapt and hardwired to be as conservative as possible with energy output (it’s an evolutionary adaptation to survive). If you stimulate it with physical stress (exercise) it’s gets better at handling that stress. The heart itself is a muscle and it strengthens. As it strengthens it can cope with more physical stress at a lower heart rate.
So whilst you may view it as a bad thing that you’re burning fewer calories in your spin class / Hiit workout etc it’s actually a fantastic measure of progress and fitness. It takes you less effort over time to perform a task that used to require much more physical effort. This should be celebrated!
It’s also a great reminder not to get too obsessed with those calorie burns. Aside from the fact that they’re not very accurate anyway, they will decrease over time and that’s a good thing! Yes you’ll burn fewer calories, but as I’ve often said you shouldn’t be eating back those calories anyway, they’re just a great measure of activity levels and progress! So if you’re exercising regularly and noticing this pattern don’t be sad – be proud! You’re getting stronger!
Happy Tuesday 🤗