June 10 (Reuters) - Olympians including Dutch marathon

runner Abdi Nageeye are using a new tool they hope will boost

their medal chances this summer: tiny monitors that attach to

the skin to track blood glucose levels.

Continuous glucose monitors or CGMs, were developed for use

by diabetes patients but their makers, led by Abbott and

Dexcom ( DXCM ), also spy opportunities in sports and wellness.

The Paris Olympics, which start on July 26, are an

opportunity to showcase the technology - even though there is as

yet no proof it can boost athletic performance.

"I do see a day where CGM is certainly going to be used

outside of diabetes in a big way," said Dexcom's ( DXCM ) Chief Operating

Officer Jacob Leach.

Diabetes patients remain the CGM specialist's commercial

focus, he told Reuters, but Dexcom ( DXCM ) is also working with

researchers on future use to optimise athletic performance. He

would not disclose details.

The CGM market is already worth billions of dollars thanks

to demand from diabetes patients, who use the coin-sized

adhesive skin patches with a Bluetooth link to a smartphone

instead of drawing blood through a finger stick. The readings

help determine whether they need an insulin dose.

In March, Dexcom's ( DXCM ) Stelo device, targeting people with

early-stage diabetes who are not on insulin, became the first

CGM to win U.S. approval for purchase without a prescription.

Launch is planned for this summer.

Abbott introduced a CGM product for amateur and elite sports

users without diabetes in Europe as early as 2020 and has

sponsored Kenyan marathon great Eliud Kipchoge and his team

since 2021. Top athletes and their support staff have been using

CGMs to optimise calorie intake and workout intensity as they

prepare for sport events.

Abbott said it is targeting the non-diabetic consumer

market. It is eyeing a U.S. launch for its Lingo device and

smartphone app for health and wellbeing, available in Britain

since January at a cost of 120-150 pounds ($152-$190) per month.

Sales of Abbott's FreeStyle Libre range, the most commonly

used CGMs, rose 23% to $5.3 billion in 2023 on demand from

diabetes patients who value their ease of use and monitoring

precision. Dexcom ( DXCM ) saw 2023 revenue grow 24% to $3.6 billion.

Research firm GlobalData ( GLDAF ) forecasts the lifestyle CGM market

could grow nearly 15% a year to reach $9.9 billion by 2031,

partly driven by users of weight-loss drugs like Wegovy who seek

med-tech gadgets to support dieting efforts.

Other market researchers estimate the overall CGM market

including diabetic use, with suppliers like Medtronic ( MDT ),

will grow 9-10% annually over five years.

PREPARING FOR PARIS

Dutch marathoner Nageeye, who won silver at the Tokyo

Olympics, said he and his coaches are monitoring blood glucose

as an indicator of the body's available energy, part of his

quest for an "effortless run".

CGM use has guided Nageeye, who has qualified for Paris, to

work on sleeping and eating patterns so that he expends a

minimum of energy during training.

"That's your energy, actually, that's your fuel. We have to

monitor that," said Nageeye. His team has been sponsored by

Abbott since April 2021.

Australian swimmer Chelsea Hodges, who won relay gold at the

Tokyo Olympics, said CGMs had helped her remedy bouts of extreme

exhaustion and dizziness during endurance training by making

adjustments to her calorie intake and training times.

She spoke to Reuters while preparing for Paris, but recently

ended her swimming career due to hip problems.

While companies see growth potential in the gadgets, sports

nutrition scientists see a promising field of research.

"A big guesswork for endurance athletes has always been: am

I training hard enough or am I training too hard? It seems with

CGMs, we have a better understanding," said Associate Professor

Filip Larsen of the Swedish School of Sport and Health Sciences.

Larsen, also chief science officer of sports performance

consultancy firm svexa, said the firm has been analysing CGM

data collected by several athletes and teams. He said svexa is

not sponsored by any CGM maker.

Larsen warned, however, that there was little validated

science yet on how to optimise an athlete's routines using CGMs.

"Most researchers cannot give you the exact answers. In five

years, we will know 10 times as much as we do now."

But the field is abuzz with trials and experiments,

including work on glucose-measuring contact lenses.

Sports dietician Greg Cox, associate professor at

Australia's Bond University, has worked with swimmers including

Hodges and rowers, triathletes and track athletes.

Results of a trial run by his team to test how not eating

enough calories to sustain the intensity of exercise would

affect endurance athletes' glucose readings have so far been

inconclusive, and he said more research into CGMs was needed.

Both Cox and Larsen expressed scepticism about non-diabetic

consumers using the technology for health and fitness without

professional advice.

"What I see on social media is that normal, healthy people

get scared when they had one banana and their blood glucose goes

up really high for one hour. This is completely expected and a

normal response," said Larsen.

Market leader Abbott told Reuters that understanding

blood-glucose swings is key to managing one's metabolism for a

healthier life.

"While glucose spikes are normal in healthy people, we also

know that having fewer frequent and large spikes and crashes in

glucose is associated with improved energy, mood, focus, sleep,

and reduces cravings," a spokesperson said.

($1 = 0.7863 pounds)

(Additional reporting by Sriparna Roy in Bengaluru and Patricia

Weiss in Frankfurt; Editing by Josephine Mason and Catherine

Evans)