This week we get to hear from Friedrich Jassil, a dietitian and researcher in diet and physical activity in the Centre for Obesity Research at University College London. Today we are going to learn more about physical activity monitoring, which is an extremely hot topic.
Key Question: How can I monitor by physical activity?
For those who have been following this blog, you’ll know that being physically active can help you to manage your body weight, keep your muscles healthy, manage your blood sugar and fat levels and even help your immune system. We also know from Articles #10 and #11 that sitting down for too long can be bad for your body. However, many people struggle to achieve physical activity recommendations and at the same time spend too much time being sedentary. Luckily there are now some ‘tools’ that you can use to keep track of your physical activity and to remind you to take a break in between sedentary activities… As you know from the last blog post, we can measure physical activity in research labs with good accuracy or you can estimate this by knowing the metabolic equivalent (MET) of an activity and your body weight. However, there are also lots of technologies that estimate your activity.
Smartphone applications: There are lots of mobile apps that can help you track your physical activity. It can be either built-in apps (e.g. Apple Health for iPhone users) or apps that you can download for free. The basic app you can use is the step counter (pedometer) such as MyFitnessPal, MapMyWalk and StepsApp. A general recommendation is to aim for 10,000 steps daily, but a recent review has highlighted that even if you struggle to achieve this, every 1000 step increase from your baseline level could have health benefits (click here). For runners, apps such as RunKepper, Strava, MapMyRun are popular.
Wearable physical activity trackers: These devices often use a motion sensor ‘accelerometer’ to track physical activity, and some come with a built-in heart rate monitor and global positioning system (GPS) receiver. The latest generation is wrist-worn devices, for example, Fitbit, Polar, Apple, Garmin, Samsung and MyKronoz. They provide real-time feedback such as steps count, heart rate, amount of calories burned, distance travelled, the number of floors you have climbed, sleep patterns and you can even set you own fitness goals. One of the good things about these devices are that they have a function to remind you to break up sitting down time. A study has shown that wearable technologies and other health technologies are effective in reducing the time spent in sedentary activity (click here).
So how accurate are these tools? These tools are often assessed for their accuracy by comparing with gold standard (laboratory based) methods (click here), and it is important to stress that they are approximate measurements. Their accuracy will also likely depend on the outcome measure being assessed, for example, a device might be quite accurate for a simple measure like ‘steps taken’ but it might be less accurate for complex measurements such as energy expenditure (click here). This is because energy expenditure is a more complex measure and can involve lower as well as upper body movements, and it is influenced by the intensity of the activity. A real benefit of these tools is to remind people to keep moving and to provide a way to help track your progress. Research findings have shown that they can help to promote increased physical activity (click here).
The take home message: A range of technologies can help you track your activity and help you to meet your targets.
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