Why Your Tracking App Thinks Your Cardio Fitness Has Suddenly Degraded
If you’re used to keeping track of your “cardio fitness” with Fitbit, Garmin, Apple Health, or any other activity tracker or app, you may have noticed that this figure has decreased recently, or may not have increased as much as you expected. But if you keep exercising, a fall may not really mean a fall in fitness at all.
I am addressing specifically those of you who live in a climate where it is summer and the heat is somewhere between intense and severe. In other words, most of the US is right now. Naturally, we all run and bike more slowly when it ‘s hot outside, and even slower when the heat and humidity combine, making being outdoors even more excruciating.
And since fitness trackers use your workouts to calculate your cardio fitness, slowing down in the summer can affect your results.
How your app’s cardio fitness score is calculated
To understand what’s going on, it’s helpful to know how these cardio fitness metrics are calculated . While some gadgets, including Fitbits, use your resting heart rate to give you a rough estimate of when you can’t do a GPS-enabled workout, most devices use outdoor distance running to figure out how good you are. form. If you can run faster than before while maintaining the same heart rate or the same speed as before with a lower heart rate, the device concludes that you are better. (Depending on your device, other workouts may also count towards cardio fitness; Garmin, for example, can use cycling if you have the correct settings.)
This makes a lot of sense, and as a result, you can get a good guess about your VO2max that would otherwise require laboratory testing. But the algorithm does not take into account all the factors that can cause you to speed up or slow down. Some make sure to only measure cardio fitness on a flat surface, which is a good start, but as far as I can tell, no one takes the weather into account.
In hot weather, we run slower and our heart rate rises to 20 beats per minute faster as our circulatory system rearranges to keep us cool (for example, opening up more capillaries near the skin, which makes the tomato face look like a side effect) … As a result, the fitness calculations of your gadget may be reset.
I started paying attention to my fitness score back in the spring, and I enjoyed watching it slowly climb higher as I did more cardio. But on the first really hot summer morning, as I climbed the hill, the thought occurred to me: “ This will kill my account, won’t it? I’ve looked at the numbers and yes, they’ve dropped a bit since the temperature started to rise. According to my Apple Watch, my GPA was 33.5 in April, 34.6 in May, and 34.9 in June, but has now dropped to 34.5 again. The good news is that as soon as it gets colder again in the fall, my results are likely to increase again.
But more importantly, it’s a reminder that the numbers coming from your fitness tracker are just numbers that the tracker can easily measure and calculate . They are not always the most useful indicator of your fitness. Instead, pay attention to things like how much time you spend in training, how consistent you are in your training, and how you perform on the metrics that really matter to you, such as your goal time. And above all, look for trends from year to year, rather than worry about things that change from week to week or day to day. Constant hard work over the years always pays off.