Hollywood stars like Gwyneth Paltrow and Kristen Stewart made fitness trackers hip several years ago by donning them in public.
However, this group of wearable devices is now being challenged by smartwatches like the Apple Watch.
Also, a few prominent players have recently shifted their focus away from this segment. Nike has stopped making its FuelBand, and Samsung is banking more on its new smartwatch Gear S2 as fitness gadgets.
But the fitness tracker market is still in the pink of health, market watchers and vendors say.
These wearables remain relevant because of their lower prices, lighter weight and longer battery life, said market research firm ABI Research principal analyst Jonathan Collins.
"The difference in price alone will help support fitness trackers," he added.
Fitness trackers use sensors like accelerometers and gyroscopes to track steps, count the number of calories burned, and monitor sleep patterns. Newer ones also sport heart rate sensors. Smartwatches - and also the newer smartphones - come with such sensors as well.
But while prices of smartwatches like the Apple Watch and LG G Watch R start from around $400 to more than $1,000, a Xiaomi MiBand costs just $19.99.
Even high-end fitness trackers like the Fitbit Charge HR fall in a significantly lower price bracket, between $100 and $300.
"Fitness trackers need to fit seamlessly into people's daily lives, and so we have designed a broad range of devices that span multiple styles, form factors and price points from $88 to $368," said Fitbit Asia Pacific vice-president and general manager Steve Morley.
"There is still significant growth potential for fitness devices over the next five years, outpacing smartwatch shipments," Mr Collins noted.
Shipments of fitness trackers and other wellness devices will increase to 102.55 million units in 2020 from 57 million units globally this year, according to ABI Research's forecast.
Fitness trackers seen as an 'extension of self'
In Singapore, sales of fitness trackers have been rising steadily, said technology research firm GfK Asia.
In the July-to-September period, the market rose by 22 per cent compared with the second quarter.
"Current trends point to a growing market as the fitness tracker is still considered a new product," said GfK Asia's digital technology account director, Mr Gerard Tan.
Local tech retailer Challenger has sold 65 per cent more units of fitness trackers so far this year, compared to a year ago.
"Demand for fitness trackers will continue to grow as most technology enthusiasts want specific data to track their fitness goals and patterns like heart rate, distance covered and calories burned," said Challenger chief marketing officer Loo Pei Fen.
Mr Neo Wei Ren, who uses a Jawbone Up3, said a fitness tracker is more accurate than a smartphone app.
"It has additional features, such as heart rate monitoring and sleep tracking, and is always on my wrist," said the 30-year-old field engineer.
For some users, the chic design of some fitness trackers is a big draw.
Marketing executive Rebecca Koh, 24, said she wears her Jawbone Up2 because it looks like an accessory.
Insurance agent Serene Tay, 30, owns a Xiaomi MiBand. "I will wear it only if it matches my clothes. If not, I won't wear it," she said.
Looks are "absolutely" key for fitness trackers, said Jawbone's head of international product, Mr Jorgen Nordin. "Smartwatches are an extension of your smartphone, but fitness trackers are an extension of yourself," he said.
To tap into the fashion-conscious crowd, Fitbit has collaborated with lifestyle brand Tory Burch.
The latter has created a special bracelet for use with the Fitbit Flex fitness tracker.
Jawbone recently released its latest Up2 and Up3 fitness trackers in a range of vibrant colours.
A version of this article appeared in the print edition of The Straits Times on November 11, 2015, with the headline Why fitness trackers will stay on people's wrists. Subscribe