As the Chinese economy has boomed in the last decade, millions of people have entered the middle class. And the Chinese aren’t just getting wealthier, they’re getting fitter. China, it seems, is in the midst of a workout craze — and that represents a once-in-a-lifetime opportunity for venture investors to back emerging health and wellness technology companies.

Health-obsessed youth culture

In particular, China’s vast millennial population of young people aged 18-35 — more than 385 million strong — is hitting the gym, running marathons, participating in exercise classes and playing and watching sports in record numbers. This generation, the first to grow up in the “new” capitalistic China, wants far more from life than their parents did.

In keeping with the Maslow hierarchy of needs, they aren’t content with simply a roof over their head and food on the table, as were previous generations who lived in times of communist control and scarcity. China’s highly educated, internet-savvy, global-traveling young people want it all — and that includes being fit. Young women, in particular, are eager to stay trim and cultivate a toned look, sharing photos of their slim physiques on social media.

Chinese young people have caught the fitness bug so much that gym and health-club revenue in China has nearly doubled during the past five years, and is expected to total more than $5 billion this year, according to research firm IBIS World. Though that falls short of the nearly $25 billion figure in the U.S., China’s health and fitness industry is far younger and growing far faster.

“Only a couple of years ago, it would have been difficult to find Chinese women breaking a sweat while lifting weights or huffing and puffing through strenuous workouts,” read a recent Wall Street Journal article about the Chinese fitness craze. Now, companies like Nike, Under Armour, Adidas and The North Face are opening stores and growing sales in China at a breakneck clip.

Wide-ranging investment opportunities

When China adopts a craze, the number of people joining is staggering, just by sheer population size. That’s why the VC industry is so bullish on investing in sports and fitness startups, in particular in three categories.

Fitness and health apps. This broad category encompasses wellness apps, fitness trackers, content and communities and any other mobile-driven consumer wellness platform. These apps are particularly popular among the 280 million people aged 15-25 in China, who have grown up on their smartphones. Chinese youth are fashion-focused, want to look good and feel healthy and are eager to try global health crazes like yoga, pilates and marathons.

Chinese millennials continue to look for new ways to become healthier and happier.

They use apps to watch fitness videos, take part in group workouts, track their progress and monitor their eating. Apps that make fitness game-like, goal-oriented and fun are hugely popular with Chinese millennials. Companies in this category include social workout app Keep (a GGV investment), Daily Yoga, run-tracker Codoon and Yuepaoquan, which helps users find and schedule running groups. Increasingly, Chinese young people are becoming sports spectators, too, and enjoy using apps to follow and comment on their favorite teams.

Smart fitness and connected sports devices. From wearables that track steps taken or calories burned to devices that help improve your golf swing or soccer kicks, Chinese consumers love to collect data on themselves in their quest toward fitness. As investors, backing these types of device companies is also a “data play.”

Once device companies figure out ways to use this data to help people become healthier, save money, lose weight or reach other goals, they’ll become far more than “gadget” companies and more like consumer market research firms. Companies leading the pack in this respect in China include both U.S. and Chinese firms, such as Fitbit, Mi Band, Misfit and Nike+.

Freedom and the great outdoors. Chinese young people today believe in an ethos of freedom. They don’t want to be tied down to owning a house or car, and they want to be free to choose their own friends, hobbies and careers. This ethos extends to how Chinese young people play sports and engage in outdoor recreation.

Tech startups that facilitate people “getting outside” will be a huge market — everything from apps that help consumers find local soccer and basketball leagues to participate in, to those bringing people together for outdoor bootcamp training sessions.

Just three decades ago, young people in China were more worried about getting enough food ration coupons.

What’s more, this category extends to frontier-tech companies such as GGV investment Niu, maker of an electric scooter popular among urban Chinese millennials who use them not just to navigate the clogged streets of Beijing, but also to get away from the smog and stress. It’s common to see people piloting Niu scooters to the mountains and beaches on the weekends, because hiking, rock climbing and surfing are all outdoor sports young Chinese consumers are eager to experience. Taiwanese company Gogoro has likewise launched a smart scooter, as well as a battery charging infrastructure to go with it.

When you see the gyms and pilates studios dotting Beijing streets or legions of young people hiking mountain trails in their North Face jackets, it’s easy to forget that just three decades ago, young people in China were more worried about getting enough food ration coupons than they were about getting toned enough to wear a new Lululemon outfit.

But China has changed at an astonishing rate, and its young people today are just like their counterparts in other developed countries — hungry for self fulfillment and personal success. As Chinese millennials continue to look for new ways to become healthier and happier, investors are clearly banking on the China fitness boom to not only continue, but to accelerate.