No one has arms long enough to wear all of the activity-tracking wristbands currently on sale or awaiting release. These devices count your steps, measure your sleep and some even monitor your heart rate.
But do you know how this information immediately applies to your lifestyle, or what you should do with it?
The services behind these trackers need to invest in immediacy by providing useful information, ideally in real time, so we can optimize our wealth of data into action.
See also: 14 Hot Fitness Gadgets to Make You Sweat
For example, activity monitors commonly use an embedded accelerometer to measure how much a user tosses and turns in the night. Theoretically, that translates into the amount of time he spends awake, sleeping lightly or sleeping deeply.
James Park, chief executive of Fitbit, told me the results compare well to data from sleep laboratories.
However, sleep is not yet well understood. Different individuals appear to need different amounts of rest in order to function. Should my sleep target be eight hours? Perhaps I'm missing my target because I require less. Or perhaps my target shouldn't be total sleep but total deep sleep.
Travis Bogard, vice president of product management and strategy at Jawbone, says, "Everyone wants to be better, but nobody has a baseline for understanding themselves."
At the moment, most activity trackers provide that baseline, but not much else.
I need to know now, immediately, in real time: What do I need to do today to ensure I get three hours of deep sleep tonight?

Sony SmartBand and Lifelog, pictured at CES 2014.
Image: Mashable
The Jawbone app occasionally offers general suggestions, such as avoiding tablet and smartphone screens for an hour before bed, but whether they work for me personally is a matter of trial and error.
The same problem applies to heart rate. Your wristband's tracking will probably be quite accurate, but what use is the data without knowing in real time what you, individually, can do to change it? If your resting heart rate is elevated, does that mean you're getting sick or just that you've had a stressful day?
McLaren Applied Solutions, an offshoot of the Formula One motor racing firm, has been working with elite athletes for years, tracking performance and helping to deliver improvements. Geoff McGrath, chief executive of MAT, argues that consumer wearables can't yet offer anything that compares meaningfully with high-end performance management technology for athletes.
“They don’t provide a great deal of insight," says McGrath. "They are providing a raw measurement, whether it’s calories burned, heart rate or distance covered, but that doesn’t tell you how many more minutes you’ve got to train at that level. It’s not forward-looking.”
For this service to work it needs to happen in real time. Finding out that you should have drunk more water yesterday, for example, is not very useful.
McGrath adds, “I’d like to know whether I need to slow down. Am I pushing myself too hard? When you wake up in the morning can you almost anticipate what kind of day you’re going to have? And if I’m looking lousy, what can I do about it? Is it drink more coffee, take a break or drink water? Eat more sugars? I’d love it if something just told me what to do to go from ‘amber’ to ‘green.'”

Fitbit Flex and Fitbit Force bracelets.
Image: Mashable, Christina Ascani
Jawbone and Fitbit offer pretty ways to visualize data, alas, without much insight. However, there are signs of change. The Jaybird Reign fitness bracelet, announced at CES, announces when you are in the "Go Zone," a.k.a. the period of time when you should stay active, and when you should rest.
In April 2013 Jawbone acquired BodyMedia for $100 million. The former now has access to the company’s medical grade device and expertise in data analysis.
A Russian startup called GERO, also unveiled at CES, gives a glimpse of what will soon be possible. Building on research findings that tiny changes in body movement can identify chronic diseases, GERO plans to use to data from commercial activity trackers to predict diseases, such as Alzheimer's, depression, diabetes, schizophrenia and more. The predictions are 60-85% accurate, depending on the disease, but the model is likely to improve with more data.
"I think what we’ll start to see over the next couple of years is devices and tools telling people what they need to do, and I think that will be very interesting," says Park.
If mainstream users are going to get better insights, we will need smarter gadgets that collect more types of data, more accurately, which are backed by intelligent services that can turn that data into useful recommendations — immediately.
In the meantime, better recommendations might mean more sensors, shorter battery life, bulkier gadgets and higher prices, making trackers less appealing to consumers. And it will take time before analysts are confident enough in their respective data to make health recommendations by individual. If your heart rate has been elevated for the last three days, is it because you’ve been exercising too hard, a sign of a health problem or a defect in your device? Should your activity monitor tell you to see a doctor or not? And will people trust medical advice from a gadget?
We will see more fitness trackers launch before CES 2015 rolls around, but let's hope they are backed by services that offer meaningful, real-time insight. As Bogard says, "Data is good, but understanding is better."
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Shane Richmond is a technology journalist, copywriter and digital media consultant. His book, Computerised You: How wearable technology will turn us ...More