Research has been carried out into the health benefits of e-bikes, but mainly in countries where cycling is not part of everyday life. In those places, an e-bike often replaces a car or public transport, so riding one is automatically a health improvement. In the Netherlands, however, the opposite is increasingly happening: the e-bike is replacing the traditional bicycle. Much less research has been done into what that means for people’s fitness levels.
How do you measure health benefits?
In the movement lab at the University of Twente, researchers use an indoor trainer with pedal assistance. The pedals contain power meters. Movement scientist Jasper Reenalda and biomedical engineer Erik Maartens measure exactly how much effort a cyclist is putting in. The cyclist wears a heart-rate monitor and an oxygen mask. The more oxygen your body needs, the harder it works.
In turbo mode, riders need surprisingly little oxygen. At maximum assistance, cyclists use only about a quarter of the energy they would on a regular bike. Heart rate and oxygen uptake during turbo cycling are barely higher than at rest. “On the highest setting, you’re doing very little yourself,” says Jasper.
Do you ride in turbo or eco mode?
At the lowest support setting (eco mode), the picture looks quite different. Cyclists still use around 70 to 77 per cent of the energy they would use on a standard bicycle. That still requires a serious amount of pedalling. "WHO guidelines recommend at least 150 minutes of moderate-intensity exercise a week," says Jasper. "That is achievable on eco mode, although you may need to cycle further than you would on a normal city bike."
The problem is that many people are likely to choose maximum assistance instead. Often, they do not realise how much the motor is taking over or how much exercise they are giving up in return. That is exactly what Reenalda and Maartens’ research focuses on: how can people make more informed choices?
How do people actually cycle?
To answer that question, researchers also need to understand how people ride in practice. Does someone stay in a heavy gear with a low cadence, or do they shift down properly? How much power is the cyclist really producing? “People need a better understanding of what they are still contributing themselves,” says Erik.
To study that, the lab alone is not enough. In a controlled setting, researchers can attach all kinds of sensors to someone, but real behaviour has to be measured in everyday conditions. That is why the team is gradually moving their research out of the movement lab. First to the university athletics track, and eventually into normal traffic. The further you move away from the lab, the fewer sensors you can use. That makes it increasingly important to measure performance using technology already built into the bike or a smartwatch, or technology that the researchers develop themselves.
Health benefits depend on the situation
Whether an e-bike is healthy depends greatly on the rider and the situation. For children, the answer is fairly clear: they need as much physical activity as possible to develop their motor skills. In most cases, an e-bike does little to help with that.
For teenagers and young adults, the answer is more complicated. Someone who would otherwise be driven to school and has a twenty-kilometre journey benefits far more from an e-bike than from no exercise at all. But someone who lives five kilometres from school and would otherwise use a regular bike is likely to lose out on physical activity by switching to an e-bike. For older adults, an e-bike can increase mobility and help people continue cycling when they might otherwise stop altogether.
That does not mean e-bikes are inherently unhealthy. Anyone who leaves the car at home and takes an e-bike instead is still gaining health benefits, even in turbo mode. Also limited physical activity is better than sitting still in a car. And for people with physical disabilities who can no longer cycle without support, the e-bike can be life-changing.
A bike that supports when you need it
What Jasper and Erik want to understand is how a bike could better support that balance. What does a cyclist actually need, and when? They call this principle “assist as needed”. For example, a bike could adjust its level of support based on a rider’s heart rate, measured through a smartwatch. The motor would provide assistance exactly when the body needs it, rather than constantly offering maximum support.
Versions of this idea already exist in the world of sports cycling. Some lightweight electric road bikes can read data from a heart-rate monitor and only provide assistance during a strong headwind or when the rider’s heart rate becomes too high. This allows someone with a pacemaker, for instance, to safely keep up with their cycling group. For the average commuter or school pupil, however, these kinds of bikes are not yet available. Bicycle manufacturers also appear to have little interest in developing them for now.
For people who already own an e-bike, the advice is fairly straightforward: use turbo mode when necessary, but switch to eco mode whenever possible. Turbo on the way to work so you do not arrive sweaty; eco on the way home. It sounds simple, but in practice, it is often harder than that. “The temptation of turbo mode is strong,” says Jasper.
So how healthy is an e-bike?
The answer is not black and white. Yet discussions about e-bikes are often framed in extremes: either “it’s healthy because you’re moving” or “it’s just as bad as a scooter”. The reality lies somewhere in between, and differs from person to person, depending on age, fitness and circumstances.
What the research by Jasper and Erik shows is that awareness matters most. Know what you are still doing yourself. Know what the motor is taking over. And make a conscious choice. That sounds easier than it is. But it starts with understanding what is really happening when you ride.
