Cardio training has never been more in vogue. Running’s popularity is surging thanks to famous joggers like Harry Styles and Jeremy Allen White, while improving your aerobic capacity (what labcoats would call your VO2 max) is just as newsworthy, with proven links to longevity and improvements across various biomarkers.

Boosting your cardio capacity requires more than a weekly lap around the park, though. Meaningful gains are earned through significant time spent moving at an easy, conversational intensity — usually in zone 2 — interspersed with regular, high-intensity sessions that push you close to your max.

However, there’s a secret weapon that can truly upgrade your training: the eBike. Although the presence of a motor and battery might sound like you’re taking it easy, if used strategically, it can help you train smarter and boost gains. Here’s how.

Fight fatigue

Whether you’re just starting your cardio journey or looking to ramp up the hours, the first barrier you’re likely to face is fatigue. While, of course, there’s no gain without pain, an eBike can help take the sting out of proceedings, leaving enough of a training load to see an increase in your fitness without digging yourself a hole.

When it comes to specific drive units, Bosch’s Performance Line SX gives you freedom and flexibility whatever your current fitness level or goals, thanks to its five different modes. From minimal support in Eco mode through to the maximum assistance of Turbo, you can choose the level of support that best suits your riding needs and switch between modes at any time during your ride. Ideal if you get tired and need an extra bit of help getting home or up your nearest climb.

The motor’s 2kg weight makes it the lightest drive unit that Bosch produces. It’s also the most compact, meaning it integrates seamlessly into any modern eRoad, eGravel or eUrban machine – leaving a bike that looks and handles like an acoustic one.

Despite its lightweight build, the Performance Line SX packs a support ratio of 400%, a maximum power output of 600 watts and 60 Nm of torque, all of which helps riders quickly get up to speed. Even as it quietly whirrs away as you ride, it still feels like having Tour de France winner Tadej Pogacar’s legs in your back pocket.

Add to this the various features of Bosch’s eBike Flow app, which can display and record compatible ride and fitness data, including heart rate, speed, cadence and other connected metrics such as CO₂ savings, and you’ll also get integration with Strava, Garmin and Komoot for valuable social kudos. There are also particularly intuitive theft protection features, too — including its eBike locking system, which digitally locks the drive unit, rendering the machine useless to those with prying eyes — working in unison with the eBike’s parking location and security status, all monitorable via the app.

Ace intervals

To truly increase your cardio capacity, things need to get uncomfortable; pushing your aerobic abilities to their limits helps raise the overall ceiling, bringing your baseline up with it.

High-intensity interval training – short, sharp bursts interspersed with active recovery – is shown to be a sure-fire way to get such performance gains and the Performance Line SX drive unit can be a useful tool for ensuring you’re in the red when needed, while keeping the pedals ticking over when you’re not.

During high-intensity reps, you can switch off motor support and keep your power output and heart rate in the correct zone by using your phone as a display while anchored to the Bosch SmartphoneGrip. In between lactic acid-inducing efforts, you can switch motor support back on with the tap of a button to instantly start your recovery, something you can’t do on a normal bike, where keeping your recovery periods easy enough can be tricky, particularly if you’ve headed to the hills to do your session.

Take it easy

The bulk of cardio training needs to be completed in zone 2. This easy, conversational intensity forms the foundations of your aerobic system, increasing mitochondrial density — the concentration of cellular mitochondria within your muscle fibres that fuel your body’s energy needs — and expanding your capillary network, improving your heart’s efficiency and baseline endurance.

Staying in zone 2 is easier said than done, though, particularly when the gradient rises, or you’re trying to keep up with stronger riders. This is where the Performance Line SX drive unit comes into its own.

Paired with the eBike Flow app, you have access to personalisable assistance profiles that can be customised based on support, dynamics, maximum torque and maximum speed to match your fitness level and the terrain you’ll be tackling, guaranteeing you’ll never be out of puff. Plus, there’s always the option of Sprint Mode — which provides more support, the faster you pedal — particularly handy when you’re racing for a sign and chasing bragging rights.

For more information on the Performance Line SX drive unit and Bosch’s entire eBike portfolio, visit www.bosch-ebike.com

Charlie Allenby is a London-based freelance writer with over a decade of experience writing about running, cycling and adventure sports for the likes of Runner’s World, Cycling Plus, Cycling Weekly, Time Out London and The Guardian. His running journey started with the Royal Parks Half in 2017 and he’s been hooked ever since, ticking off multiple marathons with a current PB of 2:43. In 2024, he started dabbling in the world of ultramarathons, pushing his body and mind to their limits in a Backyard Ultra (8 laps) and two laps of the Gloucestershire-based, Barkley-inspired Berkeley Marathons. Find him on LinkedIn