Running in Later Life: Science Debunks Age Myths for Knee Health
While all forms of exercise carry some risk of injury, there are three key strategies runners can adopt to minimise these dangers effectively.
The Truth About Running and Knee Impact
You might have heard that running is harsh on your knees, potentially causing long-term damage. But what does the scientific evidence actually say?
Running is indeed a high-impact activity. Each time your foot strikes the ground, your body absorbs a force equivalent to two to three times your body weight. This load does affect your knees, with research showing they absorb three times more force during running compared to walking.
However, this isn't necessarily detrimental. In fact, running may help maintain strong and healthy knees. Your body is a dynamic, living system that adapts and grows in response to the loads placed upon it, requiring such stress to function optimally.
How Running Benefits Bones and Cartilage
Your knee joint is remarkably robust and designed for movement. The cartilage within is a flexible connective tissue that cushions and protects the bones. Evidence indicates that when load is removed, such as during prolonged bed rest, bone and cartilage begin to deteriorate.
Studies show running temporarily reduces knee cartilage thickness, which returns to normal within a few hours post-run. Researchers propose this process may facilitate nutrient movement into the cartilage, aiding adaptation and strengthening.
Supporting this, runners typically have thicker cartilage, especially in the knees, and better bone mineral density than non-runners. Some evidence even suggests increased running may protect against osteoarthritis, though further research is needed to confirm this.
Is It Too Late to Start Running as an Older Adult?
While no strong evidence specifically examines starting running later in life, other research lines indicate it is likely safe and effective. A 2020 study found older adults aged 65 and above who began high-intensity jump training saw improvements in strength and function, with the activity deemed safe and enjoyable.
Given that this training involves higher joint loads than running, it suggests starting running in later life can be similarly beneficial. However, it's crucial to begin slowly. Your muscles and joints need time to adapt to new loads.
Start with intervals of walking and jogging, gradually increasing running distance over time to allow your body to adjust properly.
Why the Bad Reputation Persists and How to Mitigate Risks
The myth that running harms knees persists partly because nearly half of runners experience some injury annually, with knee issues being common. Most of these are overuse injuries, caused by poor load management rather than running itself—often from increasing intensity too quickly without allowing the body to adapt.
All exercise carries injury risks, but for running, several measures can help. First, progress slowly; avoid increasing mileage by more than a couple of kilometres per week to prevent injuries from sudden spikes.
Second, ensure adequate nutrition. Running burns significant energy, so consuming enough carbohydrates and protein supports recovery and may prevent overuse injuries like stress fractures. Some research also highlights the importance of sufficient calcium and Vitamin D.
Finally, consider running on softer surfaces like grass, which may reduce impact compared to concrete. Incorporating grass runs weekly when starting out can help your body adjust to the load more comfortably.
For most individuals, the health benefits of running—including improved heart and metabolic health—far outweigh the risks, especially when approached with gradual progression, strength building, and attentive listening to your body's signals.
