Tour de France riders reached the mid-point of a tortuous, three-day Pyrenean jaunt in Saint-Lary Pla d’Adet yesterday afternoon, a town more usually associated with skiing, not cycling.

Today, it’s another 145km of wickedly difficult climbs and hair-raisingly rapid descents as the peloton travels between Pau and Hautacam. By late afternoon, the worst will be over; though tomorrow’s stage is, at 208km, the fourth-longest of this year’s Tour, the route towards the beautiful town of Bergerac is comparatively flat.

Closer to home, the Tour’s television viewing figures have exceeded expectations by a considerable margin. As those enormous crowds, evident on pavements, hills and any available vantage point during the first three days as the Tour careered between Leeds and London proved, Britain’s love affair with this particular Gallic tradition shows no sign of cooling.

But we’re more than a nation of mere spectators. According to official figures, 2.1 million adults in England alone are now regularly riding bikes, an increase of 132,000 since October 2013.

Spurred by the success of riders such as Chris Froome, Mark Cavendish and Sir Bradley Wiggins, a number of British companies are benefiting from the burgeoning interest in cycling. In particular, firms manufacturing sports nutrition products are finding that demand for their wares is growing at double-digit rates.

Most Tour de France cyclists consume around two litres of fluid an hour to stay hydrated during a tough stage (as most are).

Excessive fluid loss can lead to a loss of power, so any athlete engaged in vigorous exercise must minimise fluid loss to no more than 2-3 per cent of body mass during exercise. Electrolytes, such as sodium and potassium, are also lost in the sweat and should be replaced if sweating is heavy and exercise prolonged.

To support their performances over a three-week Tour, riders must also consume enough daily energy to offset their high expenditures and adequate dietary protein to support muscle recovery.

Though cakes eaten during rides were formerly the major energy provider in riders’ diets, nutritional drinks now contribute around a quarter of their total daily energy, a point not lost on the millions of amateur riders cycling to work or for fun; nor has the sector been slow to react to the surge in demand for nutritional drinks.

Indeed, according to Ben Slater, managing partner of advertising agency Bow & Arrow, the baby-boomer market, which accounts for the largest proportion of new cyclists, offers an untapped opportunity for drinks manufacturers.

“Boomers are not these grey-haired, Werther’s Original-eating, genteel people.

“They have iPhones, they go to branded restaurants, and they are into pop culture,” he explains.

However, most existing brands may not be right for these consumers, adds Slater. He claims Red Bull “could never” attract this generation due to its youthful positioning.

Jane Geraghty, managing director of branding agency Landor, agrees: “Red Bull is as sweet as they come and that doesn’t suit an older palate.”

She argues that the sector is diversifying significantly, pointing to an increased focus on using natural ingredients and fewer “chemicals and bad sugars.”

Cyclists, particularly those of the more mature variety, are increasingly conscious of their sugar intake, a factor which is having a significant impact on the energy drinks market. GlaxoSmithKline remain the market leader in sports and energy drinks, boasting a 46 per cent share in value terms, thanks to its Lucozade Energy and Lucozade Sport brands, even though the latter’s sales declined last year due to the reduced popularity of sports drinks in general. Though nowhere near as big as GSK, a Lancashire-based company, now quoted on London’s Alternative Investment Market, is making enormous strides as more cyclists require greater energy.

Science in Sport (SiS), founded 22 years ago, produces all but two of its sports energy products in-house. When it first started, that phrase was particularly apt as members of the family business hand-rolled its energy bars on the kitchen table. It might be a tad more sophisticated, but the 1.5 million energy bars it produces today are still rolled by hand.

The methods may sound old fashioned, but SiS’s products are almost literally fuelling three of this year’s Tour de France teams: Astana, Katusha and Trek Factory Racing. Moreover, Sir Chris Hoy, Britain’s greatest-ever Olympian, is a brand ambassador, while the company supplied 24 medal-winning athletes or teams at the 2012 Olympics.

SiS has not only moved on from the kitchen table – it can produce 200 million energy gels a year – but the family structure has also been replaced by life sciences firm, Provexis, who bought the company for £11 million in 2011.

Twelve months ago, SiS was demerged from Provexis. Under chief executive Stephen Moon, a former GSK director, the company plans to take advantage of Britain’s cycling boom, as well as the growth in other endurance sports such as triathlon.

In the year ending March 31, the company’s turnover had grown by almost a quarter, to £6.8 million. Though losses of £1.2 million were accounted for by the effects of the demerger, SiS is now taking aim at the US and other overseas markets where cycling is equally popular.

Thankfully, for SiS, as cycling’s profile continues its stellar trajectory, so demand for sports nutrition products is expected to maintain its impressive growth as triathletes and cyclists turn their attention to improved performance.

According to Leatherhead Food Research, the value of the global sports nutrition market was more than £29 billion last year, although the UK market accounted for just £435 million of that total.

The scope for further growth in a domestic market in love with cycling, is glaringly obvious and SiS is expected to increase turnover beyond £10 million by the end of its 2016 financial year.

A recent commercial transaction serves to remind the company’s senior personnel of the potential prize for developing a credible, well-known (and well-used) brand.

Six years ago, GSK began tracking the progress of a rapidly-growing company called ‘Maxnutrition’, noting how popular its products had become with body-builders and other gym users. In 2010, GSK bought Maxnutrition for £162 million.

The products produced by SiS have traditionally been distributed through independent cycle shops, though more recently, larger retailers, including Tesco and Sainsbury’s have begun stocking them.

Assuming cycling’s popularity continue to grow, SiS’s impressive growth appears likely to follow suit.

Should Astana emerge victorious in tomorrow’s mountain stage between Pau and Hautacam, one wonders whether GSK might come knocking a little sooner than expected.