BARCELONA, Spain » Samsung sought Monday to frame its new Galaxy S5 smartphone as a lifestyle product, as it emphasized a built-in heart-rate sensor and improved camera features over its slightly larger size.

One of the main appeals of Samsung phones has been their size. The screen has steadily increased since the 4 inches on the original S from 2010, while the iPhone made that jump to 4 inches only in 2012 and has stayed that way since.

But the S5 pushes the screen to only 5.1 inches, measured diagonally, from 5 inches in last year’s model. Instead of size, Samsung touted the new phone’s ability to adapt its screen to changing external conditions and to dim it to avoid disturbing others nearby.

The phone has a 16 megapixel camera, sharper than the 13 megapixels in its predecessor. It promises faster auto focus and the ability to blur the foreground or background of an image to emphasize a subject.

Samsung Electronics Co. made the latest announcement during the Mobile World Congress wireless show in Barcelona, Spain.

The new phone will go on sale worldwide on April 11. The company didn’t announce a price; its predecessor sold for about $600 without phone subsidies or a contract.

The S5 has a fingerprint sensor to use in place of a passcode to unlock the phone or make payments through PayPal. It’s a feature still rare in phones, though Apple introduced it in last fall’s iPhone 5s.

Samsung’s Galaxy S series has emerged as one of the strongest challengers to Apple’s iPhones and has helped the Korean company surpass Apple as the world’s largest smartphone maker. According to Gartner, Samsung’s smartphones had a worldwide market share of 31 percent last year, compared with 16 percent for Apple’s iPhones.

A chief complaint about Samsung phones has been the company’s tendency to pack them with a slew of features, some of which don’t work well with each other or at all. Recent phones have sported an Easy Mode, with larger icons and fewer customization choices. It’s as though Samsung acknowledges that its devices have become too complex for many people to use.

Samsung showed restraint this time.

"Samsung is betting big on wellness, fingerprint reading and camera autofocus, while keeping a very similar look and feel for its hardware and software," said Nick Dillon, a senior analyst at the research firm Ovum. "The updates are so minor that on first glance most consumers would be hard pressed to notice that it has changed from the previous version."

But he said that is to be expected "given the maturity of the smartphone market and the pressure on the Samsung not to mess with its winning formula."

The heart-rate sensor on the S5 can be used before and after exercise to measure fitness activities. It’s not meant for continuous tracking. Samsung also unveiled a fitness band, Gear Fit, to complement two new computerized watches announced Sunday. Those will be available April 11 as well.

"These devices are Samsung’s commitment and vision to great experiences that matter the most to us all," Samsung European executive Jean-Daniel Ayme said.

Parents, meanwhile, will enjoy the ability to hand the phone to a kid without worry. Just place it in a kid’s mode, and only approved apps can be accessed. Your kid can’t send your boss an email or post an embarrassing picture on Facebook when all you intended was to have your kid play "Candy Crush Saga."

The phone is also water resistant.

"Our consumers do not want eye-popping technology or the most complex technology," said J.K. Shin, Samsung’s head of information technology and the mobile communications division. "Our consumers want durable design and performance. Our consumers want a simple, yet powerful camera."